Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

25 files changed, 3143 insertions, 0 deletions

diff --git a/third_party/rust/dwrote/.cargo-checksum.json b/third_party/rust/dwrote/.cargo-checksum.json
new file mode 100644
index 0000000000..7fcb22b5d9
--- /dev/null
+++ b/third_party/rust/dwrote/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"2475bea1fc2ab1cb052f254fb2bcf1bfcaba5aafe8b9acea297db498d8ec81fd","README.md":"d69d75705e2582721cbfb2d3b4b2af052c71679057a0b2ac53a22c03f1755bba","appveyor.yml":"6a91cdfbcc8c363ead82321b3be509bb7bf9cf8b90c63518d6484371abcfed48","src/bitmap_render_target.rs":"f677fa828e7466b7e8f9e5feaba7e97bd7512a2f8ee8920e5a4afad9984a9050","src/com_helpers.rs":"b3c7c545646b86b00bcf355da5ed6672596aa050b68f0b62020d8f89839267ab","src/font.rs":"295dbf78b75df4cb8a009fe381892dd00a3ef3ab49e64f9bef0477f46444d134","src/font_collection.rs":"187474bbca4845ffeb52a7535f6ff476e2cf9dd7310849ed801763e7220bdcc2","src/font_collection_impl.rs":"b27b0ae87b09e131eb807e1dee4521bff3cef66964e5494b965f12f40986d3a9","src/font_face.rs":"f5ad21c5814a094647e96cc4d08762d5da04c051344d51aa7c243d3bd86e6e11","src/font_fallback.rs":"c0c39fffdcc6747ed7513e60cbc16510515bf5b6e38d90ca9f5647bfe7c9471c","src/font_family.rs":"5abb5064933042fb5023c5f223ae4ca1942fa6f26d326279257b33a6fdb9a89c","src/font_file.rs":"d6e371f59635d908c8181bcdd3aca3ec1f4690fb7f66f7672b21fae4631a86aa","src/font_file_loader_impl.rs":"db7f93e52f4f071e5face8e8ed9d34c061d928da376b5de4c461b33d217a68ac","src/gdi_interop.rs":"7d33373f8b5af1e0ffac035b0093d72857624a5ab8696658172cd5c8b11edb2a","src/geometry_sink_impl.rs":"447fdc3179b738d981bad86052eb5820bc4d3a1f6fdd811b25617dd0847b1519","src/glyph_run_analysis.rs":"c3ad300f601f50a6b7fc8534e8b5a15c36f99c8ac495310d5e7d804e573d9c95","src/helpers.rs":"0d854b4fe40b80e9ab681a705e32bf430a16ed2f86f472b5a21243d3bb8ef242","src/lib.rs":"54b0e94f800d9c6fb8dff6e6d57f11aa9d6f78b8a63a6c5e9458bd16b2880991","src/outline_builder.rs":"0f5c842b2ffe75e21d68f93be6a3834c120bd43303d4e490fdfee9f4f964cdc4","src/rendering_params.rs":"b04db3a35fb762d8d7b2a2d660a2fd452597b3b7c522b09279d93ce889c117cd","src/test.rs":"43e8b213119c2a48d0ab252da9944c28aeaf693cedb1d69a19c8427cd474eaf9","src/text_analysis_source.rs":"8ff78ccb1271caf06aabcac6ce707685e470a7aaca0c743bf33565f85fc0ecb1","src/text_analysis_source_impl.rs":"2c435ee312b3196c17493c2ba6407a2ceae3a860a5eb83b6279ad929329d0de8","src/types.rs":"9374d8c5bac80e5e0b66188c5ff4f5f49264e15db837049932d4fd703c33746e"},"package":"439a1c2ba5611ad3ed731280541d36d2e9c4ac5e7fb818a27b604bdc5a6aa65b"}
\ No newline at end of file
diff --git a/third_party/rust/dwrote/Cargo.toml b/third_party/rust/dwrote/Cargo.toml
new file mode 100644
index 0000000000..6fac8fcff0
--- /dev/null
+++ b/third_party/rust/dwrote/Cargo.toml
@@ -0,0 +1,47 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "dwrote"
+version = "0.11.0"
+authors = ["The Servo Project Developers", "Vladimir Vukicevic <vladimir@pobox.com>"]
+description = "Lightweight binding to DirectWrite."
+license = "MPL-2.0"
+repository = "https://github.com/servo/dwrote-rs"
+
+[lib]
+name = "dwrote"
+[dependencies.lazy_static]
+version = "1"
+
+[dependencies.libc]
+version = "0.2"
+
+[dependencies.serde]
+version = "1.0"
+optional = true
+
+[dependencies.serde_derive]
+version = "1.0"
+optional = true
+
+[dependencies.winapi]
+version = "0.3.6"
+features = ["dwrite", "dwrite_1", "dwrite_3", "winnt", "unknwnbase", "libloaderapi", "winnls"]
+
+[dependencies.wio]
+version = "0.2"
+
+[features]
+default = ["serde_serialization"]
+serde_serialization = ["serde", "serde_derive"]
diff --git a/third_party/rust/dwrote/README.md b/third_party/rust/dwrote/README.md
new file mode 100644
index 0000000000..d436740898
--- /dev/null
+++ b/third_party/rust/dwrote/README.md
@@ -0,0 +1,12 @@
+# dwrote
+A thin wrapper around Windows DirectWrite for Rust
+
+Dwrote provides access to pieces of DirectWrite needed by WebRender
+and Servo.  It can be easily extended to other parts of DirectWrite,
+but full mapping of the DirectWrite API is not a goal (pull requests
+accepted, of course).
+
+There are a few additional helper functions on individual types that
+don't exist in DirectWrite, and a few have had their signatures changed,
+but for the most part this library attempts to replicate the DirectWrite
+API.
diff --git a/third_party/rust/dwrote/appveyor.yml b/third_party/rust/dwrote/appveyor.yml
new file mode 100644
index 0000000000..21508dc49c
--- /dev/null
+++ b/third_party/rust/dwrote/appveyor.yml
@@ -0,0 +1,122 @@
+# Appveyor configuration template for Rust using rustup for Rust installation
+# https://github.com/starkat99/appveyor-rust
+
+## Operating System (VM environment) ##
+
+# Rust needs at least Visual Studio 2013 Appveyor OS for MSVC targets.
+os: Visual Studio 2015
+
+## Build Matrix ##
+
+# This configuration will setup a build for each channel & target combination (12 windows
+# combinations in all).
+#
+# There are 3 channels: stable, beta, and nightly.
+#
+# Alternatively, the full version may be specified for the channel to build using that specific
+# version (e.g. channel: 1.5.0)
+#
+# The values for target are the set of windows Rust build targets. Each value is of the form
+#
+# ARCH-pc-windows-TOOLCHAIN
+#
+# Where ARCH is the target architecture, either x86_64 or i686, and TOOLCHAIN is the linker
+# toolchain to use, either msvc or gnu. See https://www.rust-lang.org/downloads.html#win-foot for
+# a description of the toolchain differences.
+# See https://github.com/rust-lang-nursery/rustup.rs/#toolchain-specification for description of
+# toolchains and host triples.
+#
+# Comment out channel/target combos you do not wish to build in CI.
+#
+# You may use the `cargoflags` and `RUSTFLAGS` variables to set additional flags for cargo commands
+# and rustc, respectively. For instance, you can uncomment the cargoflags lines in the nightly
+# channels to enable unstable features when building for nightly. Or you could add additional
+# matrix entries to test different combinations of features.
+environment:
+  matrix:
+
+### MSVC Toolchains ###
+
+  # Stable 64-bit MSVC
+   - channel: stable
+     target: x86_64-pc-windows-msvc
+  # Stable 32-bit MSVC
+  #  - channel: stable
+  #    target: i686-pc-windows-msvc
+  # Beta 64-bit MSVC
+  #  - channel: beta
+  #    target: x86_64-pc-windows-msvc
+  # Beta 32-bit MSVC
+  #  - channel: beta
+  #    target: i686-pc-windows-msvc
+  # Nightly 64-bit MSVC
+  #  - channel: nightly
+  #    target: x86_64-pc-windows-msvc
+      #cargoflags: --features "unstable"
+  # Nightly 32-bit MSVC
+  #  - channel: nightly
+  #    target: i686-pc-windows-msvc
+      #cargoflags: --features "unstable"
+
+### GNU Toolchains ###
+
+  # Stable 64-bit GNU
+  #  - channel: stable
+  #    target: x86_64-pc-windows-gnu
+  # Stable 32-bit GNU
+  #  - channel: stable
+  #    target: i686-pc-windows-gnu
+  # Beta 64-bit GNU
+  #  - channel: beta
+  #    target: x86_64-pc-windows-gnu
+  # Beta 32-bit GNU
+  #  - channel: beta
+  #    target: i686-pc-windows-gnu
+  # Nightly 64-bit GNU
+  #  - channel: nightly
+  #    target: x86_64-pc-windows-gnu
+  #    #cargoflags: --features "unstable"
+  # Nightly 32-bit GNU
+  #  - channel: nightly
+  #    target: i686-pc-windows-gnu
+      #cargoflags: --features "unstable"
+
+### Allowed failures ###
+
+# See Appveyor documentation for specific details. In short, place any channel or targets you wish
+# to allow build failures on (usually nightly at least is a wise choice). This will prevent a build
+# or test failure in the matching channels/targets from failing the entire build.
+matrix:
+  allow_failures:
+    - channel: nightly
+
+# If you only care about stable channel build failures, uncomment the following line:
+    #- channel: beta
+
+## Install Script ##
+
+# This is the most important part of the Appveyor configuration. This installs the version of Rust
+# specified by the 'channel' and 'target' environment variables from the build matrix. This uses
+# rustup to install Rust.
+#
+# For simple configurations, instead of using the build matrix, you can simply set the
+# default-toolchain and default-host manually here.
+install:
+  - appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
+  - rustup-init -yv --default-toolchain %channel% --default-host %target%
+  - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
+  - rustc -vV
+  - cargo -vV
+
+## Build Script ##
+
+# 'cargo test' takes care of building for us, so disable Appveyor's build stage. This prevents
+# the "directory does not contain a project or solution file" error.
+build: false
+
+# Uses 'cargo test' to run tests and build. Alternatively, the project may call compiled programs
+#directly or perform other testing commands. Rust will automatically be placed in the PATH
+# environment variable.
+test_script:
+  - cargo check --no-default-features
+  - cargo test --verbose %cargoflags%
diff --git a/third_party/rust/dwrote/src/bitmap_render_target.rs b/third_party/rust/dwrote/src/bitmap_render_target.rs
new file mode 100644
index 0000000000..d4753b851f
--- /dev/null
+++ b/third_party/rust/dwrote/src/bitmap_render_target.rs
@@ -0,0 +1,129 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::mem::{size_of, zeroed};
+use std::slice;
+use winapi::ctypes::c_void;
+use winapi::shared::windef::{HDC, RECT};
+use winapi::um::dcommon::DWRITE_MEASURING_MODE;
+use winapi::um::dwrite::IDWriteBitmapRenderTarget;
+use winapi::um::dwrite::{DWRITE_GLYPH_OFFSET, DWRITE_GLYPH_RUN};
+use winapi::um::wingdi::{GetCurrentObject, GetObjectW, BITMAP, OBJ_BITMAP, RGB};
+use wio::com::ComPtr;
+
+use super::{FontFace, RenderingParams};
+
+pub struct BitmapRenderTarget {
+    native: UnsafeCell<ComPtr<IDWriteBitmapRenderTarget>>,
+}
+
+impl BitmapRenderTarget {
+    pub fn take(native: ComPtr<IDWriteBitmapRenderTarget>) -> BitmapRenderTarget {
+        BitmapRenderTarget {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteBitmapRenderTarget {
+        (*self.native.get()).as_raw()
+    }
+
+    // A dip is 1/96th of an inch, so this value is the number of pixels per inch divided by 96.
+    pub fn set_pixels_per_dip(&self, ppd: f32) {
+        unsafe {
+            (*self.native.get()).SetPixelsPerDip(ppd);
+        }
+    }
+
+    pub fn get_memory_dc(&self) -> HDC {
+        unsafe { (*self.native.get()).GetMemoryDC() }
+    }
+
+    pub fn draw_glyph_run(
+        &self,
+        baseline_origin_x: f32,
+        baseline_origin_y: f32,
+        measuring_mode: DWRITE_MEASURING_MODE,
+        font_face: &FontFace,
+        em_size: f32,
+        glyph_indices: &[u16],
+        glyph_advances: &[f32],
+        glyph_offsets: &[DWRITE_GLYPH_OFFSET],
+        rendering_params: &RenderingParams,
+        color: &(f32, f32, f32),
+    ) -> RECT {
+        unsafe {
+            assert!(glyph_indices.len() == glyph_advances.len());
+            assert!(glyph_indices.len() == glyph_offsets.len());
+
+            let r = (color.0 * 255.0) as u8;
+            let g = (color.1 * 255.0) as u8;
+            let b = (color.2 * 255.0) as u8;
+
+            let mut glyph_run: DWRITE_GLYPH_RUN = zeroed();
+            glyph_run.fontFace = font_face.as_ptr();
+            glyph_run.fontEmSize = em_size;
+            glyph_run.glyphCount = glyph_indices.len() as u32;
+            glyph_run.glyphIndices = glyph_indices.as_ptr();
+            glyph_run.glyphAdvances = glyph_advances.as_ptr();
+            glyph_run.glyphOffsets = glyph_offsets.as_ptr();
+            glyph_run.isSideways = 0;
+            glyph_run.bidiLevel = 0;
+
+            let mut rect: RECT = zeroed();
+            let hr = (*self.native.get()).DrawGlyphRun(
+                baseline_origin_x,
+                baseline_origin_y,
+                measuring_mode,
+                &glyph_run,
+                rendering_params.as_ptr(),
+                RGB(r, g, b),
+                &mut rect,
+            );
+            assert!(hr == 0);
+            rect
+        }
+    }
+
+    // This function expects to have glyphs rendered in WHITE,
+    // and pulls out a u8 vector of width*height*4 size with
+    // the coverage value (we pull out R) broadcast to the alpha
+    // channel, with the color white.  That is, it performs:
+    // RGBX -> xxxR, where xxx = 0xff
+    pub fn get_opaque_values_as_mask(&self) -> Vec<u8> {
+        // Now grossness to pull out the pixels
+        unsafe {
+            let memory_dc = self.get_memory_dc();
+            let mut bitmap: BITMAP = zeroed();
+            let ret = GetObjectW(
+                GetCurrentObject(memory_dc, OBJ_BITMAP),
+                size_of::<BITMAP>() as i32,
+                &mut bitmap as *mut _ as *mut c_void,
+            );
+            assert!(ret == size_of::<BITMAP>() as i32);
+            assert!(bitmap.bmBitsPixel == 32);
+
+            let width = bitmap.bmWidth as usize;
+            let stride = bitmap.bmWidthBytes as usize;
+            let height = bitmap.bmHeight as usize;
+
+            let mut out_bytes: Vec<u8> = vec![0; width * height * 4];
+            let out_u32 =
+                slice::from_raw_parts_mut(out_bytes.as_mut_ptr() as *mut u32, width * height);
+
+            for row in 0..height {
+                let in_offset = (row * stride) as isize;
+                let in_u32 =
+                    slice::from_raw_parts(bitmap.bmBits.offset(in_offset) as *const u32, width);
+                for col in 0..width {
+                    let r = in_u32[col] & 0xff;
+                    out_u32[width * row + col] = (r << 24) | (0x00ffffffu32);
+                }
+            }
+
+            out_bytes
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/com_helpers.rs b/third_party/rust/dwrote/src/com_helpers.rs
new file mode 100644
index 0000000000..b4bcf16641
--- /dev/null
+++ b/third_party/rust/dwrote/src/com_helpers.rs
@@ -0,0 +1,127 @@
+// This is only handy for implementing a single-interface-implementing IUnknown.
+
+macro_rules! implement_iunknown {
+    ($interface:ident, $typ:ident) => {
+        IUnknownVtbl {
+            QueryInterface: {
+                #[allow(non_snake_case)]
+                unsafe extern "system" fn QueryInterface(
+                    unknown_this: *mut IUnknown,
+                    riid: REFIID,
+                    ppv_object: *mut *mut c_void,
+                ) -> HRESULT {
+                    use $crate::winapi::Interface;
+                    let this = if $crate::winapi::shared::guiddef::IsEqualGUID(
+                        &*riid,
+                        &$interface::uuidof(),
+                    ) {
+                        mem::transmute(unknown_this)
+                    } else if $crate::winapi::shared::guiddef::IsEqualGUID(
+                        &*riid,
+                        &IUnknown::uuidof(),
+                    ) {
+                        mem::transmute(unknown_this)
+                    } else {
+                        return $crate::winapi::shared::winerror::E_NOINTERFACE;
+                    };
+
+                    (*unknown_this).AddRef();
+                    *ppv_object = this;
+                    return S_OK;
+                }
+                QueryInterface
+            },
+            AddRef: {
+                unsafe extern "system" fn AddRef(unknown_this: *mut IUnknown) -> ULONG {
+                    let this = $typ::from_interface(unknown_this);
+                    let count = this.refcount.fetch_add(1, atomic::Ordering::Relaxed) + 1;
+                    count as ULONG
+                }
+                AddRef
+            },
+            Release: {
+                unsafe extern "system" fn Release(unknown_this: *mut IUnknown) -> ULONG {
+                    let this = $typ::from_interface(unknown_this);
+                    let count = this.refcount.fetch_sub(1, atomic::Ordering::Release) - 1;
+                    if count == 0 {
+                        <$typ as Com<$interface>>::destroy(unknown_this as *mut $interface);
+                    }
+                    count as ULONG
+                }
+                Release
+            },
+        }
+    };
+    (static $interface:ident, $typ:ident) => {
+        IUnknownVtbl {
+            QueryInterface: {
+                #[allow(non_snake_case)]
+                unsafe extern "system" fn QueryInterface(
+                    unknown_this: *mut IUnknown,
+                    riid: REFIID,
+                    ppvObject: *mut *mut $crate::winapi::ctypes::c_void,
+                ) -> HRESULT {
+                    use $crate::winapi::Interface;
+                    let this = if $crate::winapi::shared::guiddef::IsEqualGUID(
+                        &*riid,
+                        &$interface::uuidof(),
+                    ) {
+                        mem::transmute(unknown_this)
+                    } else if $crate::winapi::shared::guiddef::IsEqualGUID(
+                        &*riid,
+                        &IUnknown::uuidof(),
+                    ) {
+                        mem::transmute(unknown_this)
+                    } else {
+                        return $crate::winapi::shared::winerror::E_NOINTERFACE;
+                    };
+
+                    (*unknown_this).AddRef();
+                    *ppvObject = this;
+                    return S_OK;
+                }
+                QueryInterface
+            },
+            AddRef: {
+                // FIXME(pcwalton): Uh? Maybe we should actually reference count?
+                #[allow(non_snake_case)]
+                unsafe extern "system" fn AddRef(_: *mut IUnknown) -> ULONG {
+                    1
+                }
+                AddRef
+            },
+            Release: {
+                #[allow(non_snake_case)]
+                unsafe extern "system" fn Release(_: *mut IUnknown) -> ULONG {
+                    1
+                }
+                Release
+            },
+        }
+    };
+}
+
+#[repr(C)]
+pub struct ComRepr<Type, Vtbl>(*const Vtbl, Type);
+
+pub trait Com<Interface>
+where
+    Self: Sized,
+{
+    type Vtbl: 'static;
+
+    fn vtbl() -> &'static Self::Vtbl;
+
+    fn into_interface(self) -> *mut Interface {
+        let com = Box::new(ComRepr(Self::vtbl(), self));
+        Box::into_raw(com) as *mut Interface
+    }
+
+    unsafe fn from_interface<'a>(thing: *mut Interface) -> &'a mut Self {
+        &mut (*(thing as *mut ComRepr<Self, Self::Vtbl>)).1
+    }
+
+    unsafe fn destroy(thing: *mut Interface) {
+        Box::from_raw(thing as *mut ComRepr<Self, Self::Vtbl>);
+    }
+}
diff --git a/third_party/rust/dwrote/src/font.rs b/third_party/rust/dwrote/src/font.rs
new file mode 100644
index 0000000000..eacad1c3bf
--- /dev/null
+++ b/third_party/rust/dwrote/src/font.rs
@@ -0,0 +1,182 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::mem;
+use std::ptr;
+use winapi::shared::minwindef::{FALSE, TRUE};
+use winapi::shared::winerror::S_OK;
+use winapi::um::dwrite::IDWriteFont;
+use winapi::um::dwrite::IDWriteFontFace;
+use winapi::um::dwrite::IDWriteFontFamily;
+use winapi::um::dwrite::IDWriteLocalizedStrings;
+use winapi::um::dwrite::DWRITE_FONT_METRICS;
+use winapi::um::dwrite::DWRITE_INFORMATIONAL_STRING_FULL_NAME;
+use winapi::um::dwrite::DWRITE_INFORMATIONAL_STRING_ID;
+use winapi::um::dwrite::DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_CID_NAME;
+use winapi::um::dwrite::DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_NAME;
+use winapi::um::dwrite_1::{IDWriteFont1, DWRITE_FONT_METRICS1};
+use wio::com::ComPtr;
+
+use super::*;
+use helpers::*;
+
+pub struct Font {
+    native: UnsafeCell<ComPtr<IDWriteFont>>,
+}
+
+impl Font {
+    pub fn take(native: ComPtr<IDWriteFont>) -> Font {
+        Font {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteFont {
+        (*self.native.get()).as_raw()
+    }
+
+    pub fn to_descriptor(&self) -> FontDescriptor {
+        FontDescriptor {
+            family_name: self.family_name(),
+            stretch: self.stretch(),
+            style: self.style(),
+            weight: self.weight(),
+        }
+    }
+
+    pub fn stretch(&self) -> FontStretch {
+        unsafe { mem::transmute::<u32, FontStretch>((*self.native.get()).GetStretch()) }
+    }
+
+    pub fn style(&self) -> FontStyle {
+        unsafe { mem::transmute::<u32, FontStyle>((*self.native.get()).GetStyle()) }
+    }
+
+    pub fn weight(&self) -> FontWeight {
+        unsafe { FontWeight::from_u32((*self.native.get()).GetWeight()) }
+    }
+
+    pub fn is_monospace(&self) -> Option<bool> {
+        unsafe {
+            let font1: Option<ComPtr<IDWriteFont1>> = (*self.native.get()).cast().ok();
+            font1.map(|font| font.IsMonospacedFont() == TRUE)
+        }
+    }
+
+    pub fn simulations(&self) -> FontSimulations {
+        unsafe { mem::transmute::<u32, FontSimulations>((*self.native.get()).GetSimulations()) }
+    }
+
+    pub fn family_name(&self) -> String {
+        unsafe {
+            let mut family: *mut IDWriteFontFamily = ptr::null_mut();
+            let hr = (*self.native.get()).GetFontFamily(&mut family);
+            assert!(hr == 0);
+
+            FontFamily::take(ComPtr::from_raw(family)).name()
+        }
+    }
+
+    pub fn face_name(&self) -> String {
+        unsafe {
+            let mut names: *mut IDWriteLocalizedStrings = ptr::null_mut();
+            let hr = (*self.native.get()).GetFaceNames(&mut names);
+            assert!(hr == 0);
+
+            get_locale_string(&mut ComPtr::from_raw(names))
+        }
+    }
+
+    pub fn informational_string(&self, id: InformationalStringId) -> Option<String> {
+        unsafe {
+            let mut names: *mut IDWriteLocalizedStrings = ptr::null_mut();
+            let mut exists = FALSE;
+            let id = id as DWRITE_INFORMATIONAL_STRING_ID;
+            let hr = (*self.native.get()).GetInformationalStrings(id, &mut names, &mut exists);
+            assert!(hr == S_OK);
+            if exists == TRUE {
+                Some(get_locale_string(&mut ComPtr::from_raw(names)))
+            } else {
+                None
+            }
+        }
+    }
+
+    pub fn create_font_face(&self) -> FontFace {
+        // FIXME create_font_face should cache the FontFace and return it,
+        // there's a 1:1 relationship
+        unsafe {
+            let mut face: *mut IDWriteFontFace = ptr::null_mut();
+            let hr = (*self.native.get()).CreateFontFace(&mut face);
+            assert!(hr == 0);
+            FontFace::take(ComPtr::from_raw(face))
+        }
+    }
+
+    pub fn metrics(&self) -> FontMetrics {
+        unsafe {
+            let font_1: Option<ComPtr<IDWriteFont1>> = (*self.native.get()).cast().ok();
+            match font_1 {
+                None => {
+                    let mut metrics = mem::zeroed();
+                    (*self.native.get()).GetMetrics(&mut metrics);
+                    FontMetrics::Metrics0(metrics)
+                }
+                Some(font_1) => {
+                    let mut metrics_1 = mem::zeroed();
+                    font_1.GetMetrics(&mut metrics_1);
+                    FontMetrics::Metrics1(metrics_1)
+                }
+            }
+        }
+    }
+}
+
+impl Clone for Font {
+    fn clone(&self) -> Font {
+        unsafe {
+            Font {
+                native: UnsafeCell::new((*self.native.get()).clone()),
+            }
+        }
+    }
+}
+
+#[repr(u32)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum InformationalStringId {
+    FullName = DWRITE_INFORMATIONAL_STRING_FULL_NAME,
+    PostscriptName = DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_NAME,
+    PostscriptCidName = DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_CID_NAME,
+}
+
+/// A wrapper around the `DWRITE_FONT_METRICS` and `DWRITE_FONT_METRICS1` types.
+pub enum FontMetrics {
+    /// Windows 7.
+    Metrics0(DWRITE_FONT_METRICS),
+    /// Windows 8 and up.
+    Metrics1(DWRITE_FONT_METRICS1),
+}
+
+impl FontMetrics {
+    /// Convert self to the Metrics0 arm (throwing away additional information)
+    pub fn metrics0(self) -> DWRITE_FONT_METRICS {
+        match self {
+            FontMetrics::Metrics0(metrics) => metrics,
+            FontMetrics::Metrics1(metrics) => DWRITE_FONT_METRICS {
+                designUnitsPerEm: metrics.designUnitsPerEm,
+                ascent: metrics.ascent,
+                descent: metrics.descent,
+                lineGap: metrics.lineGap,
+                capHeight: metrics.capHeight,
+                xHeight: metrics.xHeight,
+                underlinePosition: metrics.underlinePosition,
+                underlineThickness: metrics.underlineThickness,
+                strikethroughPosition: metrics.strikethroughPosition,
+                strikethroughThickness: metrics.strikethroughThickness,
+            }
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/font_collection.rs b/third_party/rust/dwrote/src/font_collection.rs
new file mode 100644
index 0000000000..b1c99dbe50
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_collection.rs
@@ -0,0 +1,171 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::mem;
+use std::ptr;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use winapi::shared::minwindef::{BOOL, FALSE, TRUE};
+use winapi::shared::winerror::S_OK;
+use winapi::um::dwrite::IDWriteFontCollectionLoader;
+use winapi::um::dwrite::{IDWriteFont, IDWriteFontCollection, IDWriteFontFamily};
+use wio::com::ComPtr;
+
+use crate::helpers::*;
+use super::{DWriteFactory, Font, FontDescriptor, FontFace, FontFamily};
+
+static NEXT_ID: AtomicUsize = AtomicUsize::new(0);
+
+pub struct FontCollectionFamilyIterator {
+    collection: ComPtr<IDWriteFontCollection>,
+    curr: u32,
+    count: u32,
+}
+
+impl Iterator for FontCollectionFamilyIterator {
+    type Item = FontFamily;
+    fn next(&mut self) -> Option<FontFamily> {
+        if self.curr == self.count {
+            return None;
+        }
+
+        unsafe {
+            let mut family: *mut IDWriteFontFamily = ptr::null_mut();
+            let hr = self.collection.GetFontFamily(self.curr, &mut family);
+            assert!(hr == 0);
+            self.curr += 1;
+            Some(FontFamily::take(ComPtr::from_raw(family)))
+        }
+    }
+}
+
+pub struct FontCollection {
+    native: UnsafeCell<ComPtr<IDWriteFontCollection>>,
+}
+
+impl FontCollection {
+    pub fn get_system(update: bool) -> FontCollection {
+        unsafe {
+            let mut native: *mut IDWriteFontCollection = ptr::null_mut();
+            let hr = (*DWriteFactory()).GetSystemFontCollection(
+                &mut native,
+                if update { TRUE } else { FALSE },
+            );
+            assert!(hr == 0);
+
+            FontCollection {
+                native: UnsafeCell::new(ComPtr::from_raw(native)),
+            }
+        }
+    }
+
+    pub fn system() -> FontCollection {
+        FontCollection::get_system(false)
+    }
+
+    pub fn take(native: ComPtr<IDWriteFontCollection>) -> FontCollection {
+        FontCollection {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub fn from_loader(collection_loader: ComPtr<IDWriteFontCollectionLoader>) -> FontCollection {
+        unsafe {
+            let factory = DWriteFactory();
+            assert_eq!(
+                (*factory).RegisterFontCollectionLoader(collection_loader.clone().into_raw()),
+                S_OK
+            );
+            let mut collection: *mut IDWriteFontCollection = ptr::null_mut();
+            let id = NEXT_ID.fetch_add(1, Ordering::SeqCst);
+            assert_eq!(
+                (*factory).CreateCustomFontCollection(
+                    collection_loader.clone().into_raw(),
+                    &id as *const usize as *const _,
+                    mem::size_of::<AtomicUsize>() as u32,
+                    &mut collection
+                ),
+                S_OK
+            );
+            FontCollection::take(ComPtr::from_raw(collection))
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteFontCollection {
+        (*self.native.get()).as_raw()
+    }
+
+    pub fn families_iter(&self) -> FontCollectionFamilyIterator {
+        unsafe {
+            FontCollectionFamilyIterator {
+                collection: (*self.native.get()).clone(),
+                curr: 0,
+                count: (*self.native.get()).GetFontFamilyCount(),
+            }
+        }
+    }
+
+    pub fn get_font_family_count(&self) -> u32 {
+        unsafe { (*self.native.get()).GetFontFamilyCount() }
+    }
+
+    pub fn get_font_family(&self, index: u32) -> FontFamily {
+        unsafe {
+            let mut family: *mut IDWriteFontFamily = ptr::null_mut();
+            let hr = (*self.native.get()).GetFontFamily(index, &mut family);
+            assert!(hr == 0);
+            FontFamily::take(ComPtr::from_raw(family))
+        }
+    }
+
+    // Find a font matching the given font descriptor in this
+    // font collection.
+    pub fn get_font_from_descriptor(&self, desc: &FontDescriptor) -> Option<Font> {
+        if let Some(family) = self.get_font_family_by_name(&desc.family_name) {
+            let font = family.get_first_matching_font(desc.weight, desc.stretch, desc.style);
+            // Exact matches only here
+            if font.weight() == desc.weight
+                && font.stretch() == desc.stretch
+                && font.style() == desc.style
+            {
+                return Some(font);
+            }
+        }
+
+        None
+    }
+
+    pub fn get_font_from_face(&self, face: &FontFace) -> Option<Font> {
+        unsafe {
+            let mut font: *mut IDWriteFont = ptr::null_mut();
+            let hr = (*self.native.get()).GetFontFromFontFace(face.as_ptr(), &mut font);
+            if hr != 0 {
+                return None;
+            }
+            Some(Font::take(ComPtr::from_raw(font)))
+        }
+    }
+
+    pub fn get_font_family_by_name(&self, family_name: &str) -> Option<FontFamily> {
+        unsafe {
+            let mut index: u32 = 0;
+            let mut exists: BOOL = FALSE;
+            let hr = (*self.native.get()).FindFamilyName(
+                family_name.to_wide_null().as_ptr(),
+                &mut index,
+                &mut exists,
+            );
+            assert!(hr == 0);
+            if exists == FALSE {
+                return None;
+            }
+
+            let mut family: *mut IDWriteFontFamily = ptr::null_mut();
+            let hr = (*self.native.get()).GetFontFamily(index, &mut family);
+            assert!(hr == 0);
+
+            Some(FontFamily::take(ComPtr::from_raw(family)))
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/font_collection_impl.rs b/third_party/rust/dwrote/src/font_collection_impl.rs
new file mode 100644
index 0000000000..8a9d68e890
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_collection_impl.rs
@@ -0,0 +1,157 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// A temporary custom font collection that exists solely for the face-to-font mapping to work.
+
+use std::mem;
+use std::sync::atomic::AtomicUsize;
+use winapi::ctypes::c_void;
+use winapi::shared::guiddef::REFIID;
+use winapi::shared::minwindef::{BOOL, FALSE, TRUE, ULONG};
+use winapi::shared::winerror::{E_INVALIDARG, S_OK};
+use winapi::um::dwrite::IDWriteFactory;
+use winapi::um::dwrite::IDWriteFontCollectionLoader;
+use winapi::um::dwrite::IDWriteFontCollectionLoaderVtbl;
+use winapi::um::dwrite::IDWriteFontFile;
+use winapi::um::dwrite::IDWriteFontFileEnumerator;
+use winapi::um::dwrite::IDWriteFontFileEnumeratorVtbl;
+use winapi::um::unknwnbase::{IUnknown, IUnknownVtbl};
+use winapi::um::winnt::HRESULT;
+use wio::com::ComPtr;
+
+use crate::com_helpers::Com;
+use crate::FontFile;
+
+static FONT_COLLECTION_LOADER_VTBL: IDWriteFontCollectionLoaderVtbl =
+    IDWriteFontCollectionLoaderVtbl {
+        parent: implement_iunknown!(static IDWriteFontCollectionLoader,
+                                    CustomFontCollectionLoaderImpl),
+        CreateEnumeratorFromKey: CustomFontCollectionLoaderImpl_CreateEnumeratorFromKey,
+    };
+
+#[repr(C)]
+pub struct CustomFontCollectionLoaderImpl {
+    // NB: This must be the first field.
+    _refcount: AtomicUsize,
+    font_files: Vec<ComPtr<IDWriteFontFile>>,
+}
+
+impl Com<IDWriteFontCollectionLoader> for CustomFontCollectionLoaderImpl {
+    type Vtbl = IDWriteFontCollectionLoaderVtbl;
+    #[inline]
+    fn vtbl() -> &'static IDWriteFontCollectionLoaderVtbl {
+        &FONT_COLLECTION_LOADER_VTBL
+    }
+}
+
+impl Com<IUnknown> for CustomFontCollectionLoaderImpl {
+    type Vtbl = IUnknownVtbl;
+    #[inline]
+    fn vtbl() -> &'static IUnknownVtbl {
+        &FONT_COLLECTION_LOADER_VTBL.parent
+    }
+}
+
+impl CustomFontCollectionLoaderImpl {
+    pub fn new(font_files: &[FontFile]) -> ComPtr<IDWriteFontCollectionLoader> {
+        unsafe {
+            ComPtr::from_raw(
+                CustomFontCollectionLoaderImpl {
+                    _refcount: AtomicUsize::new(1),
+                    font_files: font_files.iter().map(|file| file.as_com_ptr()).collect(),
+                }
+                .into_interface(),
+            )
+        }
+    }
+}
+
+#[allow(non_snake_case)]
+unsafe extern "system" fn CustomFontCollectionLoaderImpl_CreateEnumeratorFromKey(
+    this: *mut IDWriteFontCollectionLoader,
+    _: *mut IDWriteFactory,
+    _: *const c_void,
+    _: u32,
+    out_enumerator: *mut *mut IDWriteFontFileEnumerator,
+) -> HRESULT {
+    let this = CustomFontCollectionLoaderImpl::from_interface(this);
+    let enumerator = CustomFontFileEnumeratorImpl::new((*this).font_files.clone());
+    let enumerator = ComPtr::<IDWriteFontFileEnumerator>::from_raw(enumerator.into_interface());
+    *out_enumerator = enumerator.as_raw();
+    mem::forget(enumerator);
+    S_OK
+}
+
+#[repr(C)]
+struct CustomFontFileEnumeratorImpl {
+    // NB(pcwalton): This must be the first field.
+    _refcount: AtomicUsize,
+    font_files: Vec<ComPtr<IDWriteFontFile>>,
+    index: isize,
+}
+
+impl Com<IDWriteFontFileEnumerator> for CustomFontFileEnumeratorImpl {
+    type Vtbl = IDWriteFontFileEnumeratorVtbl;
+    #[inline]
+    fn vtbl() -> &'static IDWriteFontFileEnumeratorVtbl {
+        &FONT_FILE_ENUMERATOR_VTBL
+    }
+}
+
+impl Com<IUnknown> for CustomFontFileEnumeratorImpl {
+    type Vtbl = IUnknownVtbl;
+    #[inline]
+    fn vtbl() -> &'static IUnknownVtbl {
+        &FONT_FILE_ENUMERATOR_VTBL.parent
+    }
+}
+
+static FONT_FILE_ENUMERATOR_VTBL: IDWriteFontFileEnumeratorVtbl = IDWriteFontFileEnumeratorVtbl {
+    parent: implement_iunknown!(static IDWriteFontFileEnumerator, CustomFontFileEnumeratorImpl),
+    GetCurrentFontFile: CustomFontFileEnumeratorImpl_GetCurrentFontFile,
+    MoveNext: CustomFontFileEnumeratorImpl_MoveNext,
+};
+
+impl CustomFontFileEnumeratorImpl {
+    pub fn new(font_files: Vec<ComPtr<IDWriteFontFile>>) -> CustomFontFileEnumeratorImpl {
+        CustomFontFileEnumeratorImpl {
+            _refcount: AtomicUsize::new(1),
+            font_files,
+            index: -1,
+        }
+    }
+}
+
+#[allow(non_snake_case)]
+unsafe extern "system" fn CustomFontFileEnumeratorImpl_GetCurrentFontFile(
+    this: *mut IDWriteFontFileEnumerator,
+    out_font_file: *mut *mut IDWriteFontFile,
+) -> HRESULT {
+    let this = CustomFontFileEnumeratorImpl::from_interface(this);
+    if (*this).index < 0 || (*this).index >= (*this).font_files.len() as isize {
+        return E_INVALIDARG;
+    }
+    let new_font_file = (*this).font_files[(*this).index as usize].clone();
+    *out_font_file = new_font_file.as_raw();
+    mem::forget(new_font_file);
+    S_OK
+}
+
+#[allow(non_snake_case)]
+unsafe extern "system" fn CustomFontFileEnumeratorImpl_MoveNext(
+    this: *mut IDWriteFontFileEnumerator,
+    has_current_file: *mut BOOL,
+) -> HRESULT {
+    let this = CustomFontFileEnumeratorImpl::from_interface(this);
+    let font_file_count = (*this).font_files.len() as isize;
+    if (*this).index < font_file_count {
+        (*this).index += 1
+    }
+    *has_current_file = if (*this).index >= 0 && (*this).index < font_file_count {
+        TRUE
+    } else {
+        FALSE
+    };
+    S_OK
+}
diff --git a/third_party/rust/dwrote/src/font_face.rs b/third_party/rust/dwrote/src/font_face.rs
new file mode 100644
index 0000000000..be0091e797
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_face.rs
@@ -0,0 +1,377 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::mem::{self, zeroed};
+use std::ptr;
+use std::slice;
+use winapi::ctypes::c_void;
+use winapi::shared::minwindef::{BOOL, FALSE, TRUE};
+use winapi::shared::winerror::S_OK;
+use winapi::um::dcommon::DWRITE_MEASURING_MODE;
+use winapi::um::dwrite::IDWriteRenderingParams;
+use winapi::um::dwrite::DWRITE_FONT_FACE_TYPE_TRUETYPE;
+use winapi::um::dwrite::{IDWriteFontFace, IDWriteFontFile};
+use winapi::um::dwrite::{DWRITE_FONT_FACE_TYPE_BITMAP, DWRITE_FONT_FACE_TYPE_CFF};
+use winapi::um::dwrite::{DWRITE_FONT_FACE_TYPE_RAW_CFF, DWRITE_FONT_FACE_TYPE_TYPE1};
+use winapi::um::dwrite::{DWRITE_FONT_FACE_TYPE_TRUETYPE_COLLECTION, DWRITE_FONT_FACE_TYPE_VECTOR};
+use winapi::um::dwrite::{DWRITE_FONT_SIMULATIONS, DWRITE_GLYPH_METRICS};
+use winapi::um::dwrite::{DWRITE_GLYPH_OFFSET, DWRITE_MATRIX, DWRITE_RENDERING_MODE};
+use winapi::um::dwrite::{DWRITE_RENDERING_MODE_DEFAULT, DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC};
+use winapi::um::dwrite_1::IDWriteFontFace1;
+use winapi::um::dwrite_3::{IDWriteFontFace5, IDWriteFontResource, DWRITE_FONT_AXIS_VALUE};
+use wio::com::ComPtr;
+
+use super::{DWriteFactory, DefaultDWriteRenderParams, FontFile, FontMetrics};
+use crate::com_helpers::Com;
+use crate::geometry_sink_impl::GeometrySinkImpl;
+use crate::outline_builder::OutlineBuilder;
+
+pub struct FontFace {
+    native: UnsafeCell<ComPtr<IDWriteFontFace>>,
+    face5: UnsafeCell<Option<ComPtr<IDWriteFontFace5>>>,
+}
+
+impl FontFace {
+    pub fn take(native: ComPtr<IDWriteFontFace>) -> FontFace {
+        let cell = UnsafeCell::new(native);
+        FontFace {
+            native: cell,
+            face5: UnsafeCell::new(None),
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteFontFace {
+        (*self.native.get()).as_raw()
+    }
+
+    unsafe fn get_raw_files(&self) -> Vec<*mut IDWriteFontFile> {
+        let mut number_of_files: u32 = 0;
+        let hr = (*self.native.get()).GetFiles(&mut number_of_files, ptr::null_mut());
+        assert!(hr == 0);
+
+        let mut file_ptrs: Vec<*mut IDWriteFontFile> =
+            vec![ptr::null_mut(); number_of_files as usize];
+        let hr = (*self.native.get()).GetFiles(&mut number_of_files, file_ptrs.as_mut_ptr());
+        assert!(hr == 0);
+        file_ptrs
+    }
+
+    pub fn get_files(&self) -> Vec<FontFile> {
+        unsafe {
+            let file_ptrs = self.get_raw_files();
+            file_ptrs
+                .iter()
+                .map(|p| FontFile::take(ComPtr::from_raw(*p)))
+                .collect()
+        }
+    }
+
+    pub fn create_font_face_with_simulations(
+        &self,
+        simulations: DWRITE_FONT_SIMULATIONS,
+    ) -> FontFace {
+        unsafe {
+            let file_ptrs = self.get_raw_files();
+            let face_type = (*self.native.get()).GetType();
+            let face_index = (*self.native.get()).GetIndex();
+            let mut face: *mut IDWriteFontFace = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateFontFace(
+                face_type,
+                file_ptrs.len() as u32,
+                file_ptrs.as_ptr(),
+                face_index,
+                simulations,
+                &mut face,
+            );
+            for p in file_ptrs {
+                let _ = ComPtr::<IDWriteFontFile>::from_raw(p);
+            }
+            assert!(hr == 0);
+            FontFace::take(ComPtr::from_raw(face))
+        }
+    }
+
+    pub fn get_glyph_count(&self) -> u16 {
+        unsafe { (*self.native.get()).GetGlyphCount() }
+    }
+
+    pub fn metrics(&self) -> FontMetrics {
+        unsafe {
+            let font_1: Option<ComPtr<IDWriteFontFace1>> = (*self.native.get()).cast().ok();
+            match font_1 {
+                None => {
+                    let mut metrics = mem::zeroed();
+                    (*self.native.get()).GetMetrics(&mut metrics);
+                    FontMetrics::Metrics0(metrics)
+                }
+                Some(font_1) => {
+                    let mut metrics_1 = mem::zeroed();
+                    font_1.GetMetrics(&mut metrics_1);
+                    FontMetrics::Metrics1(metrics_1)
+                }
+            }
+        }
+    }
+
+    pub fn get_glyph_indices(&self, code_points: &[u32]) -> Vec<u16> {
+        unsafe {
+            let mut glyph_indices: Vec<u16> = vec![0; code_points.len()];
+            let hr = (*self.native.get()).GetGlyphIndices(
+                code_points.as_ptr(),
+                code_points.len() as u32,
+                glyph_indices.as_mut_ptr(),
+            );
+            assert!(hr == 0);
+            glyph_indices
+        }
+    }
+
+    pub fn get_design_glyph_metrics(
+        &self,
+        glyph_indices: &[u16],
+        is_sideways: bool,
+    ) -> Vec<DWRITE_GLYPH_METRICS> {
+        unsafe {
+            let mut metrics: Vec<DWRITE_GLYPH_METRICS> = vec![zeroed(); glyph_indices.len()];
+            let hr = (*self.native.get()).GetDesignGlyphMetrics(
+                glyph_indices.as_ptr(),
+                glyph_indices.len() as u32,
+                metrics.as_mut_ptr(),
+                is_sideways as BOOL,
+            );
+            assert!(hr == 0);
+            metrics
+        }
+    }
+
+    pub fn get_gdi_compatible_glyph_metrics(
+        &self,
+        em_size: f32,
+        pixels_per_dip: f32,
+        transform: *const DWRITE_MATRIX,
+        use_gdi_natural: bool,
+        glyph_indices: &[u16],
+        is_sideways: bool,
+    ) -> Vec<DWRITE_GLYPH_METRICS> {
+        unsafe {
+            let mut metrics: Vec<DWRITE_GLYPH_METRICS> = vec![zeroed(); glyph_indices.len()];
+            let hr = (*self.native.get()).GetGdiCompatibleGlyphMetrics(
+                em_size,
+                pixels_per_dip,
+                transform,
+                use_gdi_natural as BOOL,
+                glyph_indices.as_ptr(),
+                glyph_indices.len() as u32,
+                metrics.as_mut_ptr(),
+                is_sideways as BOOL,
+            );
+            assert!(hr == 0);
+            metrics
+        }
+    }
+
+    /// Returns the contents of the OpenType table with the given tag.
+    ///
+    /// NB: The bytes of the tag are reversed! You probably want to use the `u32::swap_bytes()`
+    /// method on the tag value before calling this method.
+    pub fn get_font_table(&self, opentype_table_tag: u32) -> Option<Vec<u8>> {
+        unsafe {
+            let mut table_data_ptr: *const u8 = ptr::null_mut();
+            let mut table_size: u32 = 0;
+            let mut table_context: *mut c_void = ptr::null_mut();
+            let mut exists: BOOL = FALSE;
+
+            let hr = (*self.native.get()).TryGetFontTable(
+                opentype_table_tag,
+                &mut table_data_ptr as *mut *const _ as *mut *const c_void,
+                &mut table_size,
+                &mut table_context,
+                &mut exists,
+            );
+            assert!(hr == 0);
+
+            if exists == FALSE {
+                return None;
+            }
+
+            let table_bytes = slice::from_raw_parts(table_data_ptr, table_size as usize).to_vec();
+
+            (*self.native.get()).ReleaseFontTable(table_context);
+
+            Some(table_bytes)
+        }
+    }
+
+    pub fn get_recommended_rendering_mode(
+        &self,
+        em_size: f32,
+        pixels_per_dip: f32,
+        measure_mode: DWRITE_MEASURING_MODE,
+        rendering_params: *mut IDWriteRenderingParams,
+    ) -> DWRITE_RENDERING_MODE {
+        unsafe {
+            let mut render_mode: DWRITE_RENDERING_MODE = DWRITE_RENDERING_MODE_DEFAULT;
+            let hr = (*self.native.get()).GetRecommendedRenderingMode(
+                em_size,
+                pixels_per_dip,
+                measure_mode,
+                rendering_params,
+                &mut render_mode,
+            );
+
+            if hr != 0 {
+                return DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC;
+            }
+
+            render_mode
+        }
+    }
+
+    pub fn get_recommended_rendering_mode_default_params(
+        &self,
+        em_size: f32,
+        pixels_per_dip: f32,
+        measure_mode: DWRITE_MEASURING_MODE,
+    ) -> DWRITE_RENDERING_MODE {
+        self.get_recommended_rendering_mode(
+            em_size,
+            pixels_per_dip,
+            measure_mode,
+            DefaultDWriteRenderParams(),
+        )
+    }
+
+    pub fn get_glyph_run_outline(
+        &self,
+        em_size: f32,
+        glyph_indices: &[u16],
+        glyph_advances: Option<&[f32]>,
+        glyph_offsets: Option<&[DWRITE_GLYPH_OFFSET]>,
+        is_sideways: bool,
+        is_right_to_left: bool,
+        outline_builder: Box<dyn OutlineBuilder>,
+    ) {
+        unsafe {
+            let glyph_advances = match glyph_advances {
+                None => ptr::null(),
+                Some(glyph_advances) => {
+                    assert_eq!(glyph_advances.len(), glyph_indices.len());
+                    glyph_advances.as_ptr()
+                }
+            };
+            let glyph_offsets = match glyph_offsets {
+                None => ptr::null(),
+                Some(glyph_offsets) => {
+                    assert_eq!(glyph_offsets.len(), glyph_indices.len());
+                    glyph_offsets.as_ptr()
+                }
+            };
+            let is_sideways = if is_sideways { TRUE } else { FALSE };
+            let is_right_to_left = if is_right_to_left { TRUE } else { FALSE };
+            let geometry_sink = GeometrySinkImpl::new(outline_builder);
+            let geometry_sink = geometry_sink.into_interface();
+            let hr = (*self.native.get()).GetGlyphRunOutline(
+                em_size,
+                glyph_indices.as_ptr(),
+                glyph_advances,
+                glyph_offsets,
+                glyph_indices.len() as u32,
+                is_sideways,
+                is_right_to_left,
+                geometry_sink,
+            );
+            assert_eq!(hr, S_OK);
+        }
+    }
+
+    #[inline]
+    pub fn get_type(&self) -> FontFaceType {
+        unsafe {
+            match (*self.native.get()).GetType() {
+                DWRITE_FONT_FACE_TYPE_CFF => FontFaceType::Cff,
+                DWRITE_FONT_FACE_TYPE_RAW_CFF => FontFaceType::RawCff,
+                DWRITE_FONT_FACE_TYPE_TRUETYPE => FontFaceType::TrueType,
+                DWRITE_FONT_FACE_TYPE_TRUETYPE_COLLECTION => FontFaceType::TrueTypeCollection,
+                DWRITE_FONT_FACE_TYPE_TYPE1 => FontFaceType::Type1,
+                DWRITE_FONT_FACE_TYPE_VECTOR => FontFaceType::Vector,
+                DWRITE_FONT_FACE_TYPE_BITMAP => FontFaceType::Bitmap,
+                _ => FontFaceType::Unknown,
+            }
+        }
+    }
+
+    #[inline]
+    pub fn get_index(&self) -> u32 {
+        unsafe { (*self.native.get()).GetIndex() }
+    }
+
+    #[inline]
+    unsafe fn get_face5(&self) -> Option<ComPtr<IDWriteFontFace5>> {
+        if (*self.face5.get()).is_none() {
+            *self.face5.get() = (*self.native.get()).cast().ok()
+        }
+        (*self.face5.get()).clone()
+    }
+
+    pub fn has_variations(&self) -> bool {
+        unsafe {
+            match self.get_face5() {
+                Some(face5) => face5.HasVariations() == TRUE,
+                None => false,
+            }
+        }
+    }
+
+    pub fn create_font_face_with_variations(
+        &self,
+        simulations: DWRITE_FONT_SIMULATIONS,
+        axis_values: &[DWRITE_FONT_AXIS_VALUE],
+    ) -> Option<FontFace> {
+        unsafe {
+            if let Some(face5) = self.get_face5() {
+                let mut resource: *mut IDWriteFontResource = ptr::null_mut();
+                let hr = face5.GetFontResource(&mut resource);
+                if hr == S_OK && !resource.is_null() {
+                    let resource = ComPtr::from_raw(resource);
+                    let mut var_face: *mut IDWriteFontFace5 = ptr::null_mut();
+                    let hr = resource.CreateFontFace(
+                        simulations,
+                        axis_values.as_ptr(),
+                        axis_values.len() as u32,
+                        &mut var_face,
+                    );
+                    if hr == S_OK && !var_face.is_null() {
+                        let var_face = ComPtr::from_raw(var_face).cast().unwrap();
+                        return Some(FontFace::take(var_face));
+                    }
+                }
+            }
+            None
+        }
+    }
+}
+
+impl Clone for FontFace {
+    fn clone(&self) -> FontFace {
+        unsafe {
+            FontFace {
+                native: UnsafeCell::new((*self.native.get()).clone()),
+                face5: UnsafeCell::new(None),
+            }
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum FontFaceType {
+    Unknown,
+    Cff,
+    RawCff,
+    TrueType,
+    TrueTypeCollection,
+    Type1,
+    Vector,
+    Bitmap,
+}
diff --git a/third_party/rust/dwrote/src/font_fallback.rs b/third_party/rust/dwrote/src/font_fallback.rs
new file mode 100644
index 0000000000..1fa1338a29
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_fallback.rs
@@ -0,0 +1,94 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::ptr::null_mut;
+use winapi::um::dwrite_2::{IDWriteFactory2, IDWriteFontFallback};
+use wio::com::ComPtr;
+
+use super::*;
+
+pub struct FontFallback {
+    native: UnsafeCell<ComPtr<IDWriteFontFallback>>,
+}
+
+pub struct FallbackResult {
+    /// Length of mapped substring, in utf-16 code units.
+    pub mapped_length: usize,
+    /// The font that should be used to render the substring.
+    pub mapped_font: Option<Font>,
+    /// The scale factor to apply.
+    pub scale: f32,
+}
+
+impl FontFallback {
+    pub fn get_system_fallback() -> Option<FontFallback> {
+        unsafe {
+            let factory = ComPtr::from_raw(DWriteFactory());
+            let factory2: Option<ComPtr<IDWriteFactory2>> = factory.cast().ok();
+            std::mem::forget(factory);
+            let factory2 = factory2?;
+            let mut native = null_mut();
+            let hr = factory2.GetSystemFontFallback(&mut native);
+            assert_eq!(hr, 0);
+            Some(Self::take(ComPtr::from_raw(native)))
+        }
+    }
+
+    pub fn take(native: ComPtr<IDWriteFontFallback>) -> FontFallback {
+        FontFallback {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    // TODO: I'm following crate conventions for unsafe, but it's bullshit
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteFontFallback {
+        (*self.native.get()).as_raw()
+    }
+
+    // TODO: map_characters (main function)
+    pub fn map_characters(
+        &self,
+        text_analysis_source: &TextAnalysisSource,
+        text_position: u32,
+        text_length: u32,
+        base_font: &FontCollection,
+        base_family: Option<&str>,
+        base_weight: FontWeight,
+        base_style: FontStyle,
+        base_stretch: FontStretch,
+    ) -> FallbackResult {
+        unsafe {
+            let mut font = null_mut();
+            let mut mapped_length = 0;
+            let mut scale = 0.0;
+            let hr = (*self.as_ptr()).MapCharacters(
+                text_analysis_source.as_ptr(),
+                text_position,
+                text_length,
+                base_font.as_ptr(),
+                base_family
+                    .map(|s| s.to_wide_null().as_mut_ptr())
+                    .unwrap_or(null_mut()),
+                base_weight.t(),
+                base_style.t(),
+                base_stretch.t(),
+                &mut mapped_length,
+                &mut font,
+                &mut scale,
+            );
+            assert_eq!(hr, 0);
+            let mapped_font = if font.is_null() {
+                None
+            } else {
+                Some(Font::take(ComPtr::from_raw(font)))
+            };
+            FallbackResult {
+                mapped_length: mapped_length as usize,
+                mapped_font,
+                scale,
+            }
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/font_family.rs b/third_party/rust/dwrote/src/font_family.rs
new file mode 100644
index 0000000000..72f13b6a5a
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_family.rs
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::ptr;
+use winapi::um::dwrite::IDWriteLocalizedStrings;
+use winapi::um::dwrite::{IDWriteFont, IDWriteFontCollection, IDWriteFontFamily};
+use wio::com::ComPtr;
+
+use super::*;
+use helpers::*;
+
+pub struct FontFamily {
+    native: UnsafeCell<ComPtr<IDWriteFontFamily>>,
+}
+
+impl FontFamily {
+    pub fn take(native: ComPtr<IDWriteFontFamily>) -> FontFamily {
+        FontFamily {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteFontFamily {
+        (*self.native.get()).as_raw()
+    }
+
+    pub fn name(&self) -> String {
+        unsafe {
+            let mut family_names: *mut IDWriteLocalizedStrings = ptr::null_mut();
+            let hr = (*self.native.get()).GetFamilyNames(&mut family_names);
+            assert!(hr == 0);
+
+            get_locale_string(&mut ComPtr::from_raw(family_names))
+        }
+    }
+
+    pub fn get_first_matching_font(
+        &self,
+        weight: FontWeight,
+        stretch: FontStretch,
+        style: FontStyle,
+    ) -> Font {
+        unsafe {
+            let mut font: *mut IDWriteFont = ptr::null_mut();
+            let hr = (*self.native.get()).GetFirstMatchingFont(
+                weight.t(),
+                stretch.t(),
+                style.t(),
+                &mut font,
+            );
+            assert!(hr == 0);
+            Font::take(ComPtr::from_raw(font))
+        }
+    }
+
+    pub fn get_font_collection(&self) -> FontCollection {
+        unsafe {
+            let mut collection: *mut IDWriteFontCollection = ptr::null_mut();
+            let hr = (*self.native.get()).GetFontCollection(&mut collection);
+            assert!(hr == 0);
+            FontCollection::take(ComPtr::from_raw(collection))
+        }
+    }
+
+    pub fn get_font_count(&self) -> u32 {
+        unsafe { (*self.native.get()).GetFontCount() }
+    }
+
+    pub fn get_font(&self, index: u32) -> Font {
+        unsafe {
+            let mut font: *mut IDWriteFont = ptr::null_mut();
+            let hr = (*self.native.get()).GetFont(index, &mut font);
+            assert!(hr == 0);
+            Font::take(ComPtr::from_raw(font))
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/font_file.rs b/third_party/rust/dwrote/src/font_file.rs
new file mode 100644
index 0000000000..04ac7fb0a5
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_file.rs
@@ -0,0 +1,256 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::ffi::OsString;
+use std::os::windows::ffi::{OsStrExt, OsStringExt};
+use std::path::Path;
+use std::path::PathBuf;
+use std::ptr;
+use std::slice;
+use std::sync::Arc;
+use winapi::ctypes::c_void;
+use winapi::um::dwrite::{IDWriteFontFace, IDWriteFontFile, IDWriteFontFileStream};
+use winapi::um::dwrite::{IDWriteFontFileLoader, IDWriteLocalFontFileLoader};
+use winapi::um::dwrite::{DWRITE_FONT_FACE_TYPE, DWRITE_FONT_FILE_TYPE_UNKNOWN};
+use winapi::um::dwrite::{DWRITE_FONT_FACE_TYPE_UNKNOWN, DWRITE_FONT_SIMULATIONS};
+use winapi::um::winnt::HRESULT;
+use wio::com::ComPtr;
+
+use super::DWriteFactory;
+use crate::font_face::FontFace;
+use crate::font_file_loader_impl::DataFontHelper;
+
+pub struct FontFile {
+    native: UnsafeCell<ComPtr<IDWriteFontFile>>,
+    stream: UnsafeCell<Option<ComPtr<IDWriteFontFileStream>>>,
+    data_key: usize,
+    face_type: DWRITE_FONT_FACE_TYPE,
+}
+
+impl FontFile {
+    pub fn new_from_path<P>(path: P) -> Option<FontFile>
+    where
+        P: AsRef<Path>,
+    {
+        unsafe {
+            let mut path: Vec<u16> = path.as_ref().as_os_str().encode_wide().collect();
+            path.push(0);
+
+            let mut font_file: *mut IDWriteFontFile = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateFontFileReference(
+                path.as_ptr(),
+                ptr::null(),
+                &mut font_file,
+            );
+            if hr != 0 || font_file.is_null() {
+                return None;
+            }
+
+            let mut ff = FontFile {
+                native: UnsafeCell::new(ComPtr::from_raw(font_file)),
+                stream: UnsafeCell::new(None),
+                data_key: 0,
+                face_type: DWRITE_FONT_FACE_TYPE_UNKNOWN,
+            };
+
+            if ff.analyze() == 0 {
+                None
+            } else {
+                Some(ff)
+            }
+        }
+    }
+
+    pub fn new_from_data(data: Arc<Vec<u8>>) -> Option<FontFile> {
+        let (font_file, font_file_stream, key) = DataFontHelper::register_font_data(data);
+
+        let mut ff = FontFile {
+            native: UnsafeCell::new(font_file),
+            stream: UnsafeCell::new(Some(font_file_stream)),
+            data_key: key,
+            face_type: DWRITE_FONT_FACE_TYPE_UNKNOWN,
+        };
+
+        if ff.analyze() == 0 {
+            None
+        } else {
+            Some(ff)
+        }
+    }
+
+    pub fn analyze_data(data: Arc<Vec<u8>>) -> u32 {
+        let (font_file, font_file_stream, key) = DataFontHelper::register_font_data(data);
+
+        let mut ff = FontFile {
+            native: UnsafeCell::new(font_file),
+            stream: UnsafeCell::new(Some(font_file_stream)),
+            data_key: key,
+            face_type: DWRITE_FONT_FACE_TYPE_UNKNOWN,
+        };
+
+        ff.analyze()
+    }
+
+    fn analyze(&mut self) -> u32 {
+        let mut face_type = DWRITE_FONT_FACE_TYPE_UNKNOWN;
+        let mut num_faces = 0;
+        unsafe {
+            let mut supported = 0;
+            let mut _file_type = DWRITE_FONT_FILE_TYPE_UNKNOWN;
+
+            let hr = (*self.native.get()).Analyze(
+                &mut supported,
+                &mut _file_type,
+                &mut face_type,
+                &mut num_faces,
+            );
+            if hr != 0 || supported == 0 {
+                return 0;
+            }
+        }
+        self.face_type = face_type;
+        num_faces as u32
+    }
+
+    pub fn take(native: ComPtr<IDWriteFontFile>) -> FontFile {
+        let mut ff = FontFile {
+            native: UnsafeCell::new(native),
+            stream: UnsafeCell::new(None),
+            data_key: 0,
+            face_type: DWRITE_FONT_FACE_TYPE_UNKNOWN,
+        };
+        ff.analyze();
+        ff
+    }
+
+    pub fn data_key(&self) -> Option<usize> {
+        if self.data_key != 0 {
+            Some(self.data_key)
+        } else {
+            None
+        }
+    }
+
+    pub(crate) unsafe fn as_com_ptr(&self) -> ComPtr<IDWriteFontFile> {
+        (*self.native.get()).clone()
+    }
+
+    // This is a helper to read the contents of this FontFile,
+    // without requiring callers to deal with loaders, keys,
+    // or streams.
+    pub fn get_font_file_bytes(&self) -> Vec<u8> {
+        unsafe {
+            let mut ref_key: *const c_void = ptr::null();
+            let mut ref_key_size: u32 = 0;
+            let hr = (*self.native.get()).GetReferenceKey(&mut ref_key, &mut ref_key_size);
+            assert!(hr == 0);
+
+            let mut loader: *mut IDWriteFontFileLoader = ptr::null_mut();
+            let hr = (*self.native.get()).GetLoader(&mut loader);
+            assert!(hr == 0);
+            let loader = ComPtr::from_raw(loader);
+
+            let mut stream: *mut IDWriteFontFileStream = ptr::null_mut();
+            let hr = loader.CreateStreamFromKey(ref_key, ref_key_size, &mut stream);
+            assert!(hr == 0);
+            let stream = ComPtr::from_raw(stream);
+
+            let mut file_size: u64 = 0;
+            let hr = stream.GetFileSize(&mut file_size);
+            assert!(hr == 0);
+
+            let mut fragment_start: *const c_void = ptr::null();
+            let mut fragment_context: *mut c_void = ptr::null_mut();
+            let hr =
+                stream.ReadFileFragment(&mut fragment_start, 0, file_size, &mut fragment_context);
+            assert!(hr == 0);
+
+            let in_ptr = slice::from_raw_parts(fragment_start as *const u8, file_size as usize);
+            let bytes = in_ptr.to_vec();
+
+            stream.ReleaseFileFragment(fragment_context);
+
+            bytes
+        }
+    }
+
+    // This is a helper to get the path of a font file,
+    // without requiring callers to deal with loaders.
+    pub fn get_font_file_path(&self) -> Option<PathBuf> {
+        unsafe {
+            let mut ref_key: *const c_void = ptr::null();
+            let mut ref_key_size: u32 = 0;
+            let hr = (*self.native.get()).GetReferenceKey(&mut ref_key, &mut ref_key_size);
+            assert!(hr == 0);
+
+            let mut loader: *mut IDWriteFontFileLoader = ptr::null_mut();
+            let hr = (*self.native.get()).GetLoader(&mut loader);
+            assert!(hr == 0);
+            let loader = ComPtr::from_raw(loader);
+
+            let local_loader: ComPtr<IDWriteLocalFontFileLoader> = match loader.cast() {
+                Ok(local_loader) => local_loader,
+                Err(_) => return None,
+            };
+
+            let mut file_path_len = 0;
+            let hr =
+                local_loader.GetFilePathLengthFromKey(ref_key, ref_key_size, &mut file_path_len);
+            assert_eq!(hr, 0);
+
+            let mut file_path_buf = vec![0; file_path_len as usize + 1];
+            let hr = local_loader.GetFilePathFromKey(
+                ref_key,
+                ref_key_size,
+                file_path_buf.as_mut_ptr(),
+                file_path_len + 1,
+            );
+            assert_eq!(hr, 0);
+
+            if let Some(&0) = file_path_buf.last() {
+                file_path_buf.pop();
+            }
+
+            Some(PathBuf::from(OsString::from_wide(&file_path_buf)))
+        }
+    }
+
+    pub fn create_face(
+        &self,
+        face_index: u32,
+        simulations: DWRITE_FONT_SIMULATIONS,
+    ) -> Result<FontFace, HRESULT> {
+        unsafe {
+            let mut face: *mut IDWriteFontFace = ptr::null_mut();
+            let ptr = self.as_com_ptr();
+            let hr = (*DWriteFactory()).CreateFontFace(
+                self.face_type,
+                1,
+                &ptr.as_raw(),
+                face_index,
+                simulations,
+                &mut face,
+            );
+            if hr != 0 {
+                Err(hr)
+            } else {
+                Ok(FontFace::take(ComPtr::from_raw(face)))
+            }
+        }
+    }
+}
+
+impl Clone for FontFile {
+    fn clone(&self) -> FontFile {
+        unsafe {
+            FontFile {
+                native: UnsafeCell::new((*self.native.get()).clone()),
+                stream: UnsafeCell::new((*self.stream.get()).clone()),
+                data_key: self.data_key,
+                face_type: self.face_type,
+            }
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/font_file_loader_impl.rs b/third_party/rust/dwrote/src/font_file_loader_impl.rs
new file mode 100644
index 0000000000..30230d0db6
--- /dev/null
+++ b/third_party/rust/dwrote/src/font_file_loader_impl.rs
@@ -0,0 +1,237 @@
+#![allow(non_snake_case, non_upper_case_globals)]
+
+use std::collections::HashMap;
+use std::marker::Send;
+use std::sync::atomic::AtomicUsize;
+use std::sync::{atomic, Arc, Mutex};
+use std::{mem, ptr};
+use winapi::ctypes::c_void;
+use winapi::shared::basetsd::{UINT32, UINT64};
+use winapi::shared::guiddef::REFIID;
+use winapi::shared::minwindef::ULONG;
+use winapi::shared::winerror::{E_FAIL, E_INVALIDARG, E_NOTIMPL, S_OK};
+use winapi::um::dwrite::IDWriteFontFile;
+use winapi::um::dwrite::{IDWriteFontFileLoader, IDWriteFontFileLoaderVtbl};
+use winapi::um::dwrite::{IDWriteFontFileStream, IDWriteFontFileStreamVtbl};
+use winapi::um::unknwnbase::{IUnknown, IUnknownVtbl};
+use winapi::um::winnt::HRESULT;
+use wio::com::ComPtr;
+
+use super::DWriteFactory;
+use crate::com_helpers::*;
+
+struct FontFileLoader;
+
+const FontFileLoaderVtbl: &'static IDWriteFontFileLoaderVtbl = &IDWriteFontFileLoaderVtbl {
+    parent: implement_iunknown!(static IDWriteFontFileLoader, FontFileLoader),
+    CreateStreamFromKey: {
+        unsafe extern "system" fn CreateStreamFromKey(
+            _This: *mut IDWriteFontFileLoader,
+            fontFileReferenceKey: *const c_void,
+            fontFileReferenceKeySize: UINT32,
+            fontFileStream: *mut *mut IDWriteFontFileStream,
+        ) -> HRESULT {
+            if fontFileReferenceKey.is_null() || fontFileStream.is_null() {
+                return E_INVALIDARG;
+            }
+            assert!(fontFileReferenceKeySize == mem::size_of::<usize>() as UINT32);
+            let key = *(fontFileReferenceKey as *const usize);
+            let stream = match FONT_FILE_STREAM_MAP.lock().unwrap().get(&key) {
+                None => {
+                    *fontFileStream = ptr::null_mut();
+                    return E_FAIL;
+                }
+                Some(&FontFileStreamPtr(file_stream)) => file_stream,
+            };
+
+            // This is an addref getter, so make sure to do that!
+            (*stream).AddRef();
+
+            *fontFileStream = stream;
+            S_OK
+        }
+        CreateStreamFromKey
+    },
+};
+
+impl Com<IDWriteFontFileLoader> for FontFileLoader {
+    type Vtbl = IDWriteFontFileLoaderVtbl;
+    fn vtbl() -> &'static IDWriteFontFileLoaderVtbl {
+        FontFileLoaderVtbl
+    }
+}
+
+impl Com<IUnknown> for FontFileLoader {
+    type Vtbl = IUnknownVtbl;
+    fn vtbl() -> &'static IUnknownVtbl {
+        &FontFileLoaderVtbl.parent
+    }
+}
+
+impl FontFileLoader {
+    pub fn new() -> FontFileLoader {
+        FontFileLoader
+    }
+}
+
+unsafe impl Send for FontFileLoader {}
+unsafe impl Sync for FontFileLoader {}
+
+struct FontFileStream {
+    refcount: atomic::AtomicUsize,
+    key: usize,
+    data: Arc<Vec<u8>>,
+}
+
+const FontFileStreamVtbl: &'static IDWriteFontFileStreamVtbl = &IDWriteFontFileStreamVtbl {
+    parent: implement_iunknown!(IDWriteFontFileStream, FontFileStream),
+    ReadFileFragment: {
+        unsafe extern "system" fn ReadFileFragment(
+            This: *mut IDWriteFontFileStream,
+            fragmentStart: *mut *const c_void,
+            fileOffset: UINT64,
+            fragmentSize: UINT64,
+            fragmentContext: *mut *mut c_void,
+        ) -> HRESULT {
+            let this = FontFileStream::from_interface(This);
+            *fragmentContext = ptr::null_mut();
+            if (fileOffset + fragmentSize) as usize > this.data.len() {
+                return E_INVALIDARG;
+            }
+            let index = fileOffset as usize;
+            *fragmentStart = this.data[index..].as_ptr() as *const c_void;
+            S_OK
+        }
+        ReadFileFragment
+    },
+    ReleaseFileFragment: {
+        unsafe extern "system" fn ReleaseFileFragment(
+            _This: *mut IDWriteFontFileStream,
+            _fragmentContext: *mut c_void,
+        ) {
+        }
+        ReleaseFileFragment
+    },
+    GetFileSize: {
+        unsafe extern "system" fn GetFileSize(
+            This: *mut IDWriteFontFileStream,
+            fileSize: *mut UINT64,
+        ) -> HRESULT {
+            let this = FontFileStream::from_interface(This);
+            *fileSize = this.data.len() as UINT64;
+            S_OK
+        }
+        GetFileSize
+    },
+    GetLastWriteTime: {
+        unsafe extern "system" fn GetLastWriteTime(
+            _This: *mut IDWriteFontFileStream,
+            _lastWriteTime: *mut UINT64,
+        ) -> HRESULT {
+            E_NOTIMPL
+        }
+        GetLastWriteTime
+    },
+};
+
+impl FontFileStream {
+    pub fn new(key: usize, data: Arc<Vec<u8>>) -> FontFileStream {
+        FontFileStream {
+            refcount: AtomicUsize::new(1),
+            key,
+            data,
+        }
+    }
+}
+
+impl Drop for FontFileStream {
+    fn drop(&mut self) {
+        DataFontHelper::unregister_font_data(self.key);
+    }
+}
+
+impl Com<IDWriteFontFileStream> for FontFileStream {
+    type Vtbl = IDWriteFontFileStreamVtbl;
+    fn vtbl() -> &'static IDWriteFontFileStreamVtbl {
+        FontFileStreamVtbl
+    }
+}
+
+impl Com<IUnknown> for FontFileStream {
+    type Vtbl = IUnknownVtbl;
+    fn vtbl() -> &'static IUnknownVtbl {
+        &FontFileStreamVtbl.parent
+    }
+}
+
+struct FontFileStreamPtr(*mut IDWriteFontFileStream);
+
+unsafe impl Send for FontFileStreamPtr {}
+
+static mut FONT_FILE_KEY: atomic::AtomicUsize = AtomicUsize::new(0);
+
+#[derive(Clone)]
+struct FontFileLoaderWrapper(ComPtr<IDWriteFontFileLoader>);
+
+unsafe impl Send for FontFileLoaderWrapper {}
+unsafe impl Sync for FontFileLoaderWrapper {}
+
+lazy_static! {
+    static ref FONT_FILE_STREAM_MAP: Mutex<HashMap<usize, FontFileStreamPtr>> =
+        { Mutex::new(HashMap::new()) };
+    static ref FONT_FILE_LOADER: Mutex<FontFileLoaderWrapper> = {
+        unsafe {
+            let ffl_native = FontFileLoader::new();
+            let ffl = ComPtr::<IDWriteFontFileLoader>::from_raw(ffl_native.into_interface());
+            let hr = (*DWriteFactory()).RegisterFontFileLoader(ffl.as_raw());
+            assert!(hr == 0);
+            Mutex::new(FontFileLoaderWrapper(ffl))
+        }
+    };
+}
+
+pub struct DataFontHelper;
+
+impl DataFontHelper {
+    pub fn register_font_data(
+        font_data: Arc<Vec<u8>>,
+    ) -> (
+        ComPtr<IDWriteFontFile>,
+        ComPtr<IDWriteFontFileStream>,
+        usize,
+    ) {
+        unsafe {
+            let key = FONT_FILE_KEY.fetch_add(1, atomic::Ordering::Relaxed);
+            let font_file_stream_native = FontFileStream::new(key, font_data);
+            let font_file_stream: ComPtr<IDWriteFontFileStream> =
+                ComPtr::from_raw(font_file_stream_native.into_interface());
+
+            {
+                let mut map = FONT_FILE_STREAM_MAP.lock().unwrap();
+                map.insert(key, FontFileStreamPtr(font_file_stream.as_raw()));
+            }
+
+            let mut font_file: *mut IDWriteFontFile = ptr::null_mut();
+            {
+                let loader = FONT_FILE_LOADER.lock().unwrap();
+                let hr = (*DWriteFactory()).CreateCustomFontFileReference(
+                    mem::transmute(&key),
+                    mem::size_of::<usize>() as UINT32,
+                    loader.0.as_raw(),
+                    &mut font_file,
+                );
+                assert!(hr == S_OK);
+            }
+            let font_file = ComPtr::from_raw(font_file);
+
+            (font_file, font_file_stream, key)
+        }
+    }
+
+    fn unregister_font_data(key: usize) {
+        let mut map = FONT_FILE_STREAM_MAP.lock().unwrap();
+        if map.remove(&key).is_none() {
+            panic!("unregister_font_data: trying to unregister key that is no longer registered");
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/gdi_interop.rs b/third_party/rust/dwrote/src/gdi_interop.rs
new file mode 100644
index 0000000000..fcf27947c8
--- /dev/null
+++ b/third_party/rust/dwrote/src/gdi_interop.rs
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::ptr;
+use winapi::um::dwrite::IDWriteBitmapRenderTarget;
+use winapi::um::dwrite::IDWriteGdiInterop;
+use wio::com::ComPtr;
+
+use super::{BitmapRenderTarget, DWriteFactory};
+
+pub struct GdiInterop {
+    native: UnsafeCell<ComPtr<IDWriteGdiInterop>>,
+}
+
+impl GdiInterop {
+    pub fn create() -> GdiInterop {
+        unsafe {
+            let mut native: *mut IDWriteGdiInterop = ptr::null_mut();
+            let hr = (*DWriteFactory()).GetGdiInterop(&mut native);
+            assert!(hr == 0);
+            GdiInterop::take(ComPtr::from_raw(native))
+        }
+    }
+
+    pub fn take(native: ComPtr<IDWriteGdiInterop>) -> GdiInterop {
+        GdiInterop {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub fn create_bitmap_render_target(&self, width: u32, height: u32) -> BitmapRenderTarget {
+        unsafe {
+            let mut native: *mut IDWriteBitmapRenderTarget = ptr::null_mut();
+            let hr = (*self.native.get()).CreateBitmapRenderTarget(
+                ptr::null_mut(),
+                width,
+                height,
+                &mut native,
+            );
+            assert!(hr == 0);
+            BitmapRenderTarget::take(ComPtr::from_raw(native))
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/geometry_sink_impl.rs b/third_party/rust/dwrote/src/geometry_sink_impl.rs
new file mode 100644
index 0000000000..2f2f7550a2
--- /dev/null
+++ b/third_party/rust/dwrote/src/geometry_sink_impl.rs
@@ -0,0 +1,127 @@
+#![allow(non_snake_case, non_upper_case_globals)]
+
+use std::mem;
+use std::slice;
+use std::sync::atomic::AtomicUsize;
+use winapi::shared::guiddef::REFIID;
+use winapi::shared::minwindef::{UINT, ULONG};
+use winapi::shared::winerror::S_OK;
+use winapi::um::d2d1::{ID2D1SimplifiedGeometrySink, ID2D1SimplifiedGeometrySinkVtbl};
+use winapi::um::d2d1::{D2D1_BEZIER_SEGMENT, D2D1_FIGURE_BEGIN, D2D1_FIGURE_END};
+use winapi::um::d2d1::{D2D1_FIGURE_END_CLOSED, D2D1_FILL_MODE, D2D1_PATH_SEGMENT, D2D1_POINT_2F};
+use winapi::um::unknwnbase::{IUnknown, IUnknownVtbl};
+use winapi::um::winnt::HRESULT;
+
+use crate::com_helpers::Com;
+use crate::outline_builder::OutlineBuilder;
+
+static GEOMETRY_SINK_VTBL: ID2D1SimplifiedGeometrySinkVtbl = ID2D1SimplifiedGeometrySinkVtbl {
+    parent: implement_iunknown!(static ID2D1SimplifiedGeometrySink, GeometrySinkImpl),
+    BeginFigure: GeometrySinkImpl_BeginFigure,
+    EndFigure: GeometrySinkImpl_EndFigure,
+    AddLines: GeometrySinkImpl_AddLines,
+    AddBeziers: GeometrySinkImpl_AddBeziers,
+    Close: GeometrySinkImpl_Close,
+    SetFillMode: GeometrySinkImpl_SetFillMode,
+    SetSegmentFlags: GeometrySinkImpl_SetSegmentFlags,
+};
+
+#[repr(C)]
+pub struct GeometrySinkImpl {
+    // NB: This must be the first field.
+    _refcount: AtomicUsize,
+    outline_builder: Box<dyn OutlineBuilder>,
+}
+
+impl Com<ID2D1SimplifiedGeometrySink> for GeometrySinkImpl {
+    type Vtbl = ID2D1SimplifiedGeometrySinkVtbl;
+    #[inline]
+    fn vtbl() -> &'static ID2D1SimplifiedGeometrySinkVtbl {
+        &GEOMETRY_SINK_VTBL
+    }
+}
+
+impl Com<IUnknown> for GeometrySinkImpl {
+    type Vtbl = IUnknownVtbl;
+    #[inline]
+    fn vtbl() -> &'static IUnknownVtbl {
+        &GEOMETRY_SINK_VTBL.parent
+    }
+}
+
+impl GeometrySinkImpl {
+    pub fn new(outline_builder: Box<dyn OutlineBuilder>) -> GeometrySinkImpl {
+        GeometrySinkImpl {
+            _refcount: AtomicUsize::new(1),
+            outline_builder,
+        }
+    }
+}
+
+unsafe extern "system" fn GeometrySinkImpl_BeginFigure(
+    this: *mut ID2D1SimplifiedGeometrySink,
+    start_point: D2D1_POINT_2F,
+    _: D2D1_FIGURE_BEGIN,
+) {
+    let this = GeometrySinkImpl::from_interface(this);
+    (*this)
+        .outline_builder
+        .move_to(start_point.x, start_point.y)
+}
+
+unsafe extern "system" fn GeometrySinkImpl_EndFigure(
+    this: *mut ID2D1SimplifiedGeometrySink,
+    figure_end: D2D1_FIGURE_END,
+) {
+    let this = GeometrySinkImpl::from_interface(this);
+    if figure_end == D2D1_FIGURE_END_CLOSED {
+        (*this).outline_builder.close()
+    }
+}
+
+unsafe extern "system" fn GeometrySinkImpl_AddLines(
+    this: *mut ID2D1SimplifiedGeometrySink,
+    points: *const D2D1_POINT_2F,
+    points_count: UINT,
+) {
+    let this = GeometrySinkImpl::from_interface(this);
+    let points = slice::from_raw_parts(points, points_count as usize);
+    for point in points {
+        (*this).outline_builder.line_to(point.x, point.y)
+    }
+}
+
+unsafe extern "system" fn GeometrySinkImpl_AddBeziers(
+    this: *mut ID2D1SimplifiedGeometrySink,
+    beziers: *const D2D1_BEZIER_SEGMENT,
+    beziers_count: UINT,
+) {
+    let this = GeometrySinkImpl::from_interface(this);
+    let beziers = slice::from_raw_parts(beziers, beziers_count as usize);
+    for bezier in beziers {
+        (*this).outline_builder.curve_to(
+            bezier.point1.x,
+            bezier.point1.y,
+            bezier.point2.x,
+            bezier.point2.y,
+            bezier.point3.x,
+            bezier.point3.y,
+        )
+    }
+}
+
+unsafe extern "system" fn GeometrySinkImpl_Close(_: *mut ID2D1SimplifiedGeometrySink) -> HRESULT {
+    S_OK
+}
+
+unsafe extern "system" fn GeometrySinkImpl_SetFillMode(
+    _: *mut ID2D1SimplifiedGeometrySink,
+    _: D2D1_FILL_MODE,
+) {
+}
+
+unsafe extern "system" fn GeometrySinkImpl_SetSegmentFlags(
+    _: *mut ID2D1SimplifiedGeometrySink,
+    _: D2D1_PATH_SEGMENT,
+) {
+}
diff --git a/third_party/rust/dwrote/src/glyph_run_analysis.rs b/third_party/rust/dwrote/src/glyph_run_analysis.rs
new file mode 100644
index 0000000000..5224c60bc9
--- /dev/null
+++ b/third_party/rust/dwrote/src/glyph_run_analysis.rs
@@ -0,0 +1,107 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::mem;
+use std::ptr;
+use winapi::shared::windef::RECT;
+use winapi::um::dcommon::DWRITE_MEASURING_MODE;
+use winapi::um::dwrite::DWRITE_TEXTURE_CLEARTYPE_3x1;
+use winapi::um::dwrite::IDWriteGlyphRunAnalysis;
+use winapi::um::dwrite::{DWRITE_TEXTURE_ALIASED_1x1, DWRITE_GLYPH_RUN, DWRITE_TEXTURE_TYPE};
+use winapi::um::dwrite::{DWRITE_MATRIX, DWRITE_RENDERING_MODE};
+use winapi::um::winnt::HRESULT;
+use wio::com::ComPtr;
+
+use super::DWriteFactory;
+
+pub struct GlyphRunAnalysis {
+    native: UnsafeCell<ComPtr<IDWriteGlyphRunAnalysis>>,
+}
+
+impl GlyphRunAnalysis {
+    pub fn create(
+        glyph_run: &DWRITE_GLYPH_RUN,
+        pixels_per_dip: f32,
+        transform: Option<DWRITE_MATRIX>,
+        rendering_mode: DWRITE_RENDERING_MODE,
+        measuring_mode: DWRITE_MEASURING_MODE,
+        baseline_x: f32,
+        baseline_y: f32,
+    ) -> Result<GlyphRunAnalysis, HRESULT> {
+        unsafe {
+            let mut native: *mut IDWriteGlyphRunAnalysis = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateGlyphRunAnalysis(
+                glyph_run as *const DWRITE_GLYPH_RUN,
+                pixels_per_dip,
+                transform
+                    .as_ref()
+                    .map(|x| x as *const _)
+                    .unwrap_or(ptr::null()),
+                rendering_mode,
+                measuring_mode,
+                baseline_x,
+                baseline_y,
+                &mut native,
+            );
+            if hr != 0 {
+                Err(hr)
+            } else {
+                Ok(GlyphRunAnalysis::take(ComPtr::from_raw(native)))
+            }
+        }
+    }
+
+    pub fn take(native: ComPtr<IDWriteGlyphRunAnalysis>) -> GlyphRunAnalysis {
+        GlyphRunAnalysis {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub fn get_alpha_texture_bounds(
+        &self,
+        texture_type: DWRITE_TEXTURE_TYPE,
+    ) -> Result<RECT, HRESULT> {
+        unsafe {
+            let mut rect: RECT = mem::zeroed();
+            rect.left = 1234;
+            rect.top = 1234;
+            let hr = (*self.native.get()).GetAlphaTextureBounds(texture_type, &mut rect);
+            if hr != 0 {
+                Err(hr)
+            } else {
+                Ok(rect)
+            }
+        }
+    }
+
+    pub fn create_alpha_texture(
+        &self,
+        texture_type: DWRITE_TEXTURE_TYPE,
+        rect: RECT,
+    ) -> Result<Vec<u8>, HRESULT> {
+        unsafe {
+            let rect_pixels = (rect.right - rect.left) * (rect.bottom - rect.top);
+            let rect_bytes = rect_pixels
+                * match texture_type {
+                    DWRITE_TEXTURE_ALIASED_1x1 => 1,
+                    DWRITE_TEXTURE_CLEARTYPE_3x1 => 3,
+                    _ => panic!("bad texture type specified"),
+                };
+
+            let mut out_bytes: Vec<u8> = vec![0; rect_bytes as usize];
+            let hr = (*self.native.get()).CreateAlphaTexture(
+                texture_type,
+                &rect,
+                out_bytes.as_mut_ptr(),
+                out_bytes.len() as u32,
+            );
+            if hr != 0 {
+                Err(hr)
+            } else {
+                Ok(out_bytes)
+            }
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/helpers.rs b/third_party/rust/dwrote/src/helpers.rs
new file mode 100644
index 0000000000..804ff9e40c
--- /dev/null
+++ b/third_party/rust/dwrote/src/helpers.rs
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::ffi::OsStr;
+use std::os::windows::ffi::OsStrExt;
+use winapi::ctypes::wchar_t;
+use winapi::shared::minwindef::{BOOL, FALSE};
+use winapi::shared::winerror::S_OK;
+use winapi::um::dwrite::IDWriteLocalizedStrings;
+use winapi::um::winnls::GetUserDefaultLocaleName;
+use wio::com::ComPtr;
+
+lazy_static! {
+    static ref SYSTEM_LOCALE: Vec<wchar_t> = {
+        unsafe {
+            let mut locale: Vec<wchar_t> = vec![0; 85];
+            GetUserDefaultLocaleName(locale.as_mut_ptr(), locale.len() as i32 - 1);
+            locale
+        }
+    };
+    static ref EN_US_LOCALE: Vec<wchar_t> = { OsStr::new("en-us").to_wide_null() };
+}
+
+pub fn get_locale_string(strings: &mut ComPtr<IDWriteLocalizedStrings>) -> String {
+    unsafe {
+        let mut index: u32 = 0;
+        let mut exists: BOOL = FALSE;
+        let hr = strings.FindLocaleName((*SYSTEM_LOCALE).as_ptr(), &mut index, &mut exists);
+        if hr != S_OK || exists == FALSE {
+            let hr = strings.FindLocaleName((*EN_US_LOCALE).as_ptr(), &mut index, &mut exists);
+            if hr != S_OK || exists == FALSE {
+                // Ultimately fall back to first locale on list
+                index = 0;
+            }
+        }
+
+        let mut length: u32 = 0;
+        let hr = strings.GetStringLength(index, &mut length);
+        assert!(hr == 0);
+
+        let mut name: Vec<wchar_t> = Vec::with_capacity(length as usize + 1);
+        let hr = strings.GetString(index, name.as_mut_ptr(), length + 1);
+        assert!(hr == 0);
+        name.set_len(length as usize);
+
+        String::from_utf16(&name).ok().unwrap()
+    }
+}
+
+// ToWide from https://github.com/retep998/wio-rs/blob/master/src/wide.rs
+
+pub trait ToWide {
+    fn to_wide(&self) -> Vec<u16>;
+    fn to_wide_null(&self) -> Vec<u16>;
+}
+
+impl<T> ToWide for T
+where
+    T: AsRef<OsStr>,
+{
+    fn to_wide(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().collect()
+    }
+    fn to_wide_null(&self) -> Vec<u16> {
+        self.as_ref().encode_wide().chain(Some(0)).collect()
+    }
+}
diff --git a/third_party/rust/dwrote/src/lib.rs b/third_party/rust/dwrote/src/lib.rs
new file mode 100644
index 0000000000..b392bcaf5a
--- /dev/null
+++ b/third_party/rust/dwrote/src/lib.rs
@@ -0,0 +1,167 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![allow(non_upper_case_globals)]
+
+#[cfg(feature = "serde_serialization")]
+extern crate serde;
+#[cfg_attr(feature = "serde_serialization", macro_use)]
+#[cfg(feature = "serde_serialization")]
+extern crate serde_derive;
+
+#[macro_use]
+extern crate lazy_static;
+extern crate libc;
+extern crate winapi;
+
+include!("types.rs");
+
+use std::ffi::CString;
+use std::ptr;
+use winapi::Interface;
+use winapi::shared::guiddef::REFIID;
+use winapi::shared::winerror::S_OK;
+use winapi::um::dwrite::DWRITE_FACTORY_TYPE;
+use winapi::um::dwrite::DWRITE_FACTORY_TYPE_SHARED;
+use winapi::um::dwrite::IDWriteFactory;
+use winapi::um::dwrite::IDWriteRenderingParams;
+use winapi::um::unknwnbase::IUnknown;
+use winapi::um::winnt::LPCSTR;
+
+pub use winapi::um::winnt::HRESULT;
+
+mod helpers;
+use helpers::ToWide;
+use std::os::raw::c_void;
+
+#[cfg(test)]
+mod test;
+
+// We still use the DWrite structs for things like metrics; re-export them
+// here
+pub use winapi::shared::windef::RECT;
+pub use winapi::um::dcommon::DWRITE_MEASURING_MODE;
+pub use winapi::um::dcommon::{
+    DWRITE_MEASURING_MODE_GDI_CLASSIC, DWRITE_MEASURING_MODE_GDI_NATURAL,
+    DWRITE_MEASURING_MODE_NATURAL,
+};
+pub use winapi::um::dwrite::DWRITE_FONT_METRICS as FontMetrics0;
+pub use winapi::um::dwrite::DWRITE_FONT_SIMULATIONS;
+pub use winapi::um::dwrite::DWRITE_GLYPH_OFFSET as GlyphOffset;
+pub use winapi::um::dwrite::DWRITE_RENDERING_MODE;
+pub use winapi::um::dwrite::DWRITE_TEXTURE_TYPE;
+pub use winapi::um::dwrite::{DWRITE_TEXTURE_ALIASED_1x1, DWRITE_TEXTURE_CLEARTYPE_3x1};
+pub use winapi::um::dwrite::{
+    DWRITE_FONT_SIMULATIONS_BOLD, DWRITE_FONT_SIMULATIONS_NONE, DWRITE_FONT_SIMULATIONS_OBLIQUE,
+};
+pub use winapi::um::dwrite::{DWRITE_GLYPH_RUN, DWRITE_MATRIX};
+pub use winapi::um::dwrite::{
+    DWRITE_RENDERING_MODE_ALIASED, DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC,
+    DWRITE_RENDERING_MODE_CLEARTYPE_GDI_NATURAL, DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL,
+    DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC, DWRITE_RENDERING_MODE_DEFAULT,
+    DWRITE_RENDERING_MODE_GDI_CLASSIC, DWRITE_RENDERING_MODE_GDI_NATURAL,
+    DWRITE_RENDERING_MODE_NATURAL, DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC,
+    DWRITE_RENDERING_MODE_OUTLINE,
+};
+pub use winapi::um::dwrite_1::DWRITE_FONT_METRICS1 as FontMetrics1;
+pub use winapi::um::dwrite_3::DWRITE_FONT_AXIS_VALUE;
+use winapi::um::libloaderapi::{GetProcAddress, LoadLibraryW};
+
+#[macro_use]
+mod com_helpers;
+
+mod bitmap_render_target;
+pub use bitmap_render_target::BitmapRenderTarget;
+mod font;
+pub use font::{Font, FontMetrics, InformationalStringId};
+mod font_collection;
+pub use font_collection::FontCollection;
+mod font_face;
+pub use font_face::{FontFace, FontFaceType};
+mod font_fallback;
+pub use font_fallback::{FallbackResult, FontFallback};
+mod font_family;
+pub use font_family::FontFamily;
+mod font_file;
+pub use font_file::FontFile;
+mod gdi_interop;
+pub use gdi_interop::GdiInterop;
+mod outline_builder;
+pub use outline_builder::OutlineBuilder;
+mod rendering_params;
+pub use rendering_params::RenderingParams;
+mod text_analysis_source;
+pub use text_analysis_source::TextAnalysisSource;
+mod glyph_run_analysis;
+pub use glyph_run_analysis::GlyphRunAnalysis;
+
+// This is an internal implementation of FontFileLoader, for our utility
+// functions.  We don't wrap the DWriteFontFileLoader interface and
+// related things.
+mod font_file_loader_impl;
+
+// This is an implementation of `FontCollectionLoader` for client code.
+mod font_collection_impl;
+pub use font_collection_impl::CustomFontCollectionLoaderImpl;
+
+// This is an implementation of `TextAnalysisSource` for client code.
+mod text_analysis_source_impl;
+pub use text_analysis_source_impl::{
+    CustomTextAnalysisSourceImpl, NumberSubstitution, TextAnalysisSourceMethods,
+};
+
+// This is an internal implementation of `GeometrySink` so that we can
+// expose `IDWriteGeometrySink` in an idiomatic way.
+mod geometry_sink_impl;
+
+lazy_static! {
+    static ref DWRITE_FACTORY_RAW_PTR: usize = {
+        unsafe {
+            type DWriteCreateFactoryType =
+                extern "system" fn(DWRITE_FACTORY_TYPE, REFIID, *mut *mut IUnknown) -> HRESULT;
+
+            let dwrite_dll = LoadLibraryW("dwrite.dll".to_wide_null().as_ptr());
+            assert!(!dwrite_dll.is_null());
+            let create_factory_name = CString::new("DWriteCreateFactory").unwrap();
+            let dwrite_create_factory_ptr =
+                GetProcAddress(dwrite_dll, create_factory_name.as_ptr() as LPCSTR);
+            assert!(!dwrite_create_factory_ptr.is_null());
+
+            let dwrite_create_factory = mem::transmute::<*const c_void, DWriteCreateFactoryType>(
+                dwrite_create_factory_ptr as *const _,
+            );
+
+            let mut factory: *mut IDWriteFactory = ptr::null_mut();
+            let hr = dwrite_create_factory(
+                DWRITE_FACTORY_TYPE_SHARED,
+                &IDWriteFactory::uuidof(),
+                &mut factory as *mut *mut IDWriteFactory as *mut *mut IUnknown,
+            );
+            assert!(hr == S_OK);
+            factory as usize
+        }
+    };
+    static ref DEFAULT_DWRITE_RENDERING_PARAMS_RAW_PTR: usize = {
+        unsafe {
+            let mut default_rendering_params: *mut IDWriteRenderingParams = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateRenderingParams(&mut default_rendering_params);
+            assert!(hr == S_OK);
+            default_rendering_params as usize
+        }
+    };
+} // end lazy static
+
+// FIXME vlad would be nice to return, say, FactoryPtr<IDWriteFactory>
+// that has a DerefMut impl, so that we can write
+// DWriteFactory().SomeOperation() as opposed to
+// (*DWriteFactory()).SomeOperation()
+#[allow(non_snake_case)]
+fn DWriteFactory() -> *mut IDWriteFactory {
+    (*DWRITE_FACTORY_RAW_PTR) as *mut IDWriteFactory
+}
+
+#[allow(non_snake_case)]
+fn DefaultDWriteRenderParams() -> *mut IDWriteRenderingParams {
+    (*DEFAULT_DWRITE_RENDERING_PARAMS_RAW_PTR) as *mut IDWriteRenderingParams
+}
diff --git a/third_party/rust/dwrote/src/outline_builder.rs b/third_party/rust/dwrote/src/outline_builder.rs
new file mode 100644
index 0000000000..7e7716b4f0
--- /dev/null
+++ b/third_party/rust/dwrote/src/outline_builder.rs
@@ -0,0 +1,6 @@
+pub trait OutlineBuilder {
+    fn move_to(&mut self, x: f32, y: f32);
+    fn line_to(&mut self, x: f32, y: f32);
+    fn curve_to(&mut self, cp0x: f32, cp0y: f32, cp1x: f32, cp1y: f32, x: f32, y: f32);
+    fn close(&mut self);
+}
diff --git a/third_party/rust/dwrote/src/rendering_params.rs b/third_party/rust/dwrote/src/rendering_params.rs
new file mode 100644
index 0000000000..977c38a34a
--- /dev/null
+++ b/third_party/rust/dwrote/src/rendering_params.rs
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cell::UnsafeCell;
+use std::ptr;
+use winapi::um::dwrite::IDWriteRenderingParams;
+use wio::com::ComPtr;
+
+use super::DWriteFactory;
+
+pub struct RenderingParams {
+    native: UnsafeCell<ComPtr<IDWriteRenderingParams>>,
+}
+
+impl RenderingParams {
+    pub fn create_for_primary_monitor() -> RenderingParams {
+        unsafe {
+            let mut native: *mut IDWriteRenderingParams = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateRenderingParams(&mut native);
+            assert!(hr == 0);
+            RenderingParams::take(ComPtr::from_raw(native))
+        }
+    }
+
+    pub fn take(native: ComPtr<IDWriteRenderingParams>) -> RenderingParams {
+        RenderingParams {
+            native: UnsafeCell::new(native),
+        }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *mut IDWriteRenderingParams {
+        (*self.native.get()).as_raw()
+    }
+}
diff --git a/third_party/rust/dwrote/src/test.rs b/third_party/rust/dwrote/src/test.rs
new file mode 100644
index 0000000000..1396ab6df6
--- /dev/null
+++ b/third_party/rust/dwrote/src/test.rs
@@ -0,0 +1,167 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use super::*;
+use std::sync::Arc;
+
+#[test]
+fn test_system_family_iter() {
+    let system_fc = FontCollection::system();
+    let count = system_fc.families_iter().count();
+    assert!(count > 0);
+    assert!(system_fc
+        .families_iter()
+        .find(|f| f.name() == "Arial")
+        .is_some());
+}
+
+#[test]
+fn test_descriptor_round_trip() {
+    let system_fc = FontCollection::system();
+
+    let arial_family = system_fc.get_font_family_by_name("Arial").unwrap();
+    let arial_font = arial_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+
+    let descriptor = arial_font.to_descriptor();
+    assert!(descriptor.family_name == "Arial");
+
+    let arial_font_2 = system_fc.get_font_from_descriptor(&descriptor).unwrap();
+    let descriptor2 = arial_font_2.to_descriptor();
+    assert_eq!(descriptor, descriptor2);
+}
+
+#[test]
+fn test_get_font_file_bytes() {
+    let system_fc = FontCollection::system();
+
+    let arial_family = system_fc.get_font_family_by_name("Arial").unwrap();
+    let arial_font = arial_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+    let face = arial_font.create_font_face();
+    let files = face.get_files();
+    assert!(files.len() > 0);
+
+    let bytes = files[0].get_font_file_bytes();
+    assert!(bytes.len() > 0);
+}
+
+#[test]
+fn test_font_file_is_monospace() {
+    let system_fc = FontCollection::system();
+
+    let arial_family = system_fc.get_font_family_by_name("Arial").unwrap();
+    let arial_font = arial_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+    assert!(arial_font.is_monospace() == Some(false));
+
+    let courier_new_family = system_fc.get_font_family_by_name("Courier New").unwrap();
+    let courier_new_font = courier_new_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+    assert!(courier_new_font.is_monospace() == Some(true));
+}
+
+#[test]
+fn test_create_font_file_from_bytes() {
+    let system_fc = FontCollection::system();
+
+    let arial_family = system_fc.get_font_family_by_name("Arial").unwrap();
+    let arial_font = arial_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+    let face = arial_font.create_font_face();
+    let files = face.get_files();
+    assert!(files.len() > 0);
+
+    let bytes = files[0].get_font_file_bytes();
+    assert!(bytes.len() > 0);
+
+    // now go back
+    let new_font = FontFile::new_from_data(Arc::new(bytes));
+    assert!(new_font.is_some());
+
+    let _new_font = new_font.unwrap();
+}
+
+#[test]
+fn test_glyph_image() {
+    let system_fc = FontCollection::system();
+    let arial_family = system_fc.get_font_family_by_name("Arial").unwrap();
+    let arial_font = arial_family.get_first_matching_font(
+        FontWeight::Regular,
+        FontStretch::Normal,
+        FontStyle::Normal,
+    );
+
+    let face = arial_font.create_font_face();
+    let a_index = face.get_glyph_indices(&['A' as u32])[0];
+
+    let gm = face.get_design_glyph_metrics(&[a_index], false)[0];
+
+    let device_pixel_ratio = 1.0f32;
+    let em_size = 10.0f32;
+
+    let design_units_per_em = match face.metrics() {
+        FontMetrics::Metrics0(ref metrics) => metrics.designUnitsPerEm,
+        FontMetrics::Metrics1(ref metrics) => metrics.designUnitsPerEm,
+    };
+    let design_units_per_pixel = design_units_per_em as f32 / 16.;
+
+    let scaled_design_units_to_pixels = (em_size * device_pixel_ratio) / design_units_per_pixel;
+
+    let width = (gm.advanceWidth as i32 - (gm.leftSideBearing + gm.rightSideBearing)) as f32
+        * scaled_design_units_to_pixels;
+    let height = (gm.advanceHeight as i32 - (gm.topSideBearing + gm.bottomSideBearing)) as f32
+        * scaled_design_units_to_pixels;
+    let x = (-gm.leftSideBearing) as f32 * scaled_design_units_to_pixels;
+    let y = (gm.verticalOriginY - gm.topSideBearing) as f32 * scaled_design_units_to_pixels;
+
+    // FIXME I'm pretty sure we need to do a proper RoundOut type
+    // operation on this rect to properly handle any aliasing
+    let left_i = x.floor() as i32;
+    let top_i = (height - y).floor() as i32;
+    let width_u = width.ceil() as u32;
+    let height_u = height.ceil() as u32;
+
+    println!(
+        "GlyphDimensions: {} {} {} {}",
+        left_i, top_i, width_u, height_u
+    );
+
+    let gdi_interop = GdiInterop::create();
+    let rt = gdi_interop.create_bitmap_render_target(width_u, height_u);
+    let rp = RenderingParams::create_for_primary_monitor();
+    rt.set_pixels_per_dip(device_pixel_ratio);
+    rt.draw_glyph_run(
+        x as f32,
+        y as f32,
+        DWRITE_MEASURING_MODE_NATURAL,
+        &face,
+        em_size,
+        &[a_index],
+        &[0f32],
+        &[GlyphOffset {
+            advanceOffset: 0.,
+            ascenderOffset: 0.,
+        }],
+        &rp,
+        &(255.0f32, 255.0f32, 255.0f32),
+    );
+    let bytes = rt.get_opaque_values_as_mask();
+    println!("bytes length: {}", bytes.len());
+}
diff --git a/third_party/rust/dwrote/src/text_analysis_source.rs b/third_party/rust/dwrote/src/text_analysis_source.rs
new file mode 100644
index 0000000000..cd575d62d2
--- /dev/null
+++ b/third_party/rust/dwrote/src/text_analysis_source.rs
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::borrow::Cow;
+use std::marker::PhantomData;
+use winapi::ctypes::wchar_t;
+use winapi::um::dwrite::IDWriteTextAnalysisSource;
+use wio::com::ComPtr;
+
+use super::*;
+use crate::com_helpers::Com;
+
+pub struct TextAnalysisSource<'a> {
+    native: ComPtr<IDWriteTextAnalysisSource>,
+    phantom: PhantomData<CustomTextAnalysisSourceImpl<'a>>
+}
+
+impl<'a> TextAnalysisSource<'a> {
+    /// Create a new custom TextAnalysisSource for the given text and a trait
+    /// implementation.
+    ///
+    /// Note: this method has no NumberSubsitution specified. See
+    /// `from_text_and_number_subst` if you need number substitution.
+    pub fn from_text(
+        inner: Box<dyn TextAnalysisSourceMethods + 'a>,
+        text: Cow<'a, [wchar_t]>,
+    ) -> TextAnalysisSource<'a> {
+        let native = unsafe {
+            ComPtr::from_raw(
+                CustomTextAnalysisSourceImpl::from_text_native(inner, text).into_interface()
+            )
+        };
+        TextAnalysisSource { native, phantom: PhantomData }
+    }
+
+    /// Create a new custom TextAnalysisSource for the given text and a trait
+    /// implementation.
+    ///
+    /// Note: this method only supports a single `NumberSubstitution` for the
+    /// entire string.
+    pub fn from_text_and_number_subst(
+        inner: Box<dyn TextAnalysisSourceMethods + 'a>,
+        text: Cow<'a, [wchar_t]>,
+        number_subst: NumberSubstitution,
+    ) -> TextAnalysisSource<'a> {
+        let native = unsafe {
+            ComPtr::from_raw(
+                CustomTextAnalysisSourceImpl::from_text_and_number_subst_native(
+                    inner,
+                    text,
+                    number_subst,
+                )
+                .into_interface()
+            )
+        };
+        TextAnalysisSource { native, phantom: PhantomData }
+    }
+
+    pub fn as_ptr(&self) -> *mut IDWriteTextAnalysisSource {
+        self.native.as_raw()
+    }
+}
diff --git a/third_party/rust/dwrote/src/text_analysis_source_impl.rs b/third_party/rust/dwrote/src/text_analysis_source_impl.rs
new file mode 100644
index 0000000000..44f8a65b5b
--- /dev/null
+++ b/third_party/rust/dwrote/src/text_analysis_source_impl.rs
@@ -0,0 +1,240 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! A custom implementation of the "text analysis source" interface so that
+//! we can convey data to the `FontFallback::map_characters` method.
+
+#![allow(non_snake_case)]
+
+use std::borrow::Cow;
+use std::ffi::OsStr;
+use std::mem;
+use std::os::windows::ffi::OsStrExt;
+use std::ptr::{self, null};
+use std::sync::atomic::AtomicUsize;
+use winapi::ctypes::wchar_t;
+use winapi::shared::basetsd::UINT32;
+use winapi::shared::guiddef::REFIID;
+use winapi::shared::minwindef::{FALSE, TRUE, ULONG};
+use winapi::shared::ntdef::LOCALE_NAME_MAX_LENGTH;
+use winapi::shared::winerror::{E_INVALIDARG, S_OK};
+use winapi::um::dwrite::IDWriteNumberSubstitution;
+use winapi::um::dwrite::IDWriteTextAnalysisSource;
+use winapi::um::dwrite::IDWriteTextAnalysisSourceVtbl;
+use winapi::um::dwrite::DWRITE_NUMBER_SUBSTITUTION_METHOD;
+use winapi::um::dwrite::DWRITE_READING_DIRECTION;
+use winapi::um::unknwnbase::{IUnknown, IUnknownVtbl};
+use winapi::um::winnt::HRESULT;
+use wio::com::ComPtr;
+
+use super::DWriteFactory;
+use crate::com_helpers::Com;
+use crate::helpers::ToWide;
+
+/// The Rust side of a custom text analysis source implementation.
+pub trait TextAnalysisSourceMethods {
+    /// Determine the locale for a range of text.
+    ///
+    /// Return locale and length of text (in utf-16 code units) for which the
+    /// locale is valid.
+    fn get_locale_name<'a>(&'a self, text_position: u32) -> (Cow<'a, str>, u32);
+
+    /// Get the text direction for the paragraph.
+    fn get_paragraph_reading_direction(&self) -> DWRITE_READING_DIRECTION;
+}
+
+#[repr(C)]
+pub struct CustomTextAnalysisSourceImpl<'a> {
+    // NB: This must be the first field.
+    _refcount: AtomicUsize,
+    inner: Box<dyn TextAnalysisSourceMethods + 'a>,
+    text: Cow<'a, [wchar_t]>,
+    number_subst: Option<NumberSubstitution>,
+    locale_buf: [wchar_t; LOCALE_NAME_MAX_LENGTH],
+}
+
+/// A wrapped version of an `IDWriteNumberSubstitution` object.
+pub struct NumberSubstitution {
+    native: ComPtr<IDWriteNumberSubstitution>,
+}
+
+// TODO: implement Clone, for convenience and efficiency?
+
+static TEXT_ANALYSIS_SOURCE_VTBL: IDWriteTextAnalysisSourceVtbl = IDWriteTextAnalysisSourceVtbl {
+    parent: implement_iunknown!(static IDWriteTextAnalysisSource, CustomTextAnalysisSourceImpl),
+    GetLocaleName: CustomTextAnalysisSourceImpl_GetLocaleName,
+    GetNumberSubstitution: CustomTextAnalysisSourceImpl_GetNumberSubstitution,
+    GetParagraphReadingDirection: CustomTextAnalysisSourceImpl_GetParagraphReadingDirection,
+    GetTextAtPosition: CustomTextAnalysisSourceImpl_GetTextAtPosition,
+    GetTextBeforePosition: CustomTextAnalysisSourceImpl_GetTextBeforePosition,
+};
+
+impl<'a> CustomTextAnalysisSourceImpl<'a> {
+    /// Create a new custom TextAnalysisSource for the given text and a trait
+    /// implementation.
+    ///
+    /// Note: this method has no NumberSubsitution specified. See
+    /// `from_text_and_number_subst_native` if you need number substitution.
+    pub fn from_text_native(
+        inner: Box<dyn TextAnalysisSourceMethods + 'a>,
+        text: Cow<'a, [wchar_t]>,
+    ) -> CustomTextAnalysisSourceImpl<'a> {
+        assert!(text.len() <= (std::u32::MAX as usize));
+        CustomTextAnalysisSourceImpl {
+            _refcount: AtomicUsize::new(1),
+            inner,
+            text,
+            number_subst: None,
+            locale_buf: [0u16; LOCALE_NAME_MAX_LENGTH],
+        }
+    }
+
+    /// Create a new custom TextAnalysisSource for the given text and a trait
+    /// implementation.
+    ///
+    /// Note: this method only supports a single `NumberSubstitution` for the
+    /// entire string.
+    pub fn from_text_and_number_subst_native(
+        inner: Box<dyn TextAnalysisSourceMethods + 'a>,
+        text: Cow<'a, [wchar_t]>,
+        number_subst: NumberSubstitution,
+    ) -> CustomTextAnalysisSourceImpl<'a> {
+        assert!(text.len() <= (std::u32::MAX as usize));
+        CustomTextAnalysisSourceImpl {
+            _refcount: AtomicUsize::new(1),
+            inner,
+            text,
+            number_subst: Some(number_subst),
+            locale_buf: [0u16; LOCALE_NAME_MAX_LENGTH],
+        }
+    }
+}
+
+impl Com<IDWriteTextAnalysisSource> for CustomTextAnalysisSourceImpl<'_> {
+    type Vtbl = IDWriteTextAnalysisSourceVtbl;
+    #[inline]
+    fn vtbl() -> &'static IDWriteTextAnalysisSourceVtbl {
+        &TEXT_ANALYSIS_SOURCE_VTBL
+    }
+}
+
+impl Com<IUnknown> for CustomTextAnalysisSourceImpl<'_> {
+    type Vtbl = IUnknownVtbl;
+    #[inline]
+    fn vtbl() -> &'static IUnknownVtbl {
+        &TEXT_ANALYSIS_SOURCE_VTBL.parent
+    }
+}
+
+unsafe extern "system" fn CustomTextAnalysisSourceImpl_GetLocaleName(
+    this: *mut IDWriteTextAnalysisSource,
+    text_position: UINT32,
+    text_length: *mut UINT32,
+    locale_name: *mut *const wchar_t,
+) -> HRESULT {
+    let this = CustomTextAnalysisSourceImpl::from_interface(this);
+    let (locale, text_len) = this.inner.get_locale_name(text_position);
+
+    // Copy the locale data into the buffer
+    for (i, c) in OsStr::new(&*locale).encode_wide().chain(Some(0)).enumerate() {
+        // -1 here is deliberate: it ensures that we never write to the last character in
+        // this.locale_buf, so that the buffer is always null-terminated.
+        if i >= this.locale_buf.len() - 1 {
+            break
+        }
+
+        *this.locale_buf.get_unchecked_mut(i) = c;
+    }
+
+    *text_length = text_len;
+    *locale_name = this.locale_buf.as_ptr();
+    S_OK
+}
+
+unsafe extern "system" fn CustomTextAnalysisSourceImpl_GetNumberSubstitution(
+    this: *mut IDWriteTextAnalysisSource,
+    text_position: UINT32,
+    text_length: *mut UINT32,
+    number_substitution: *mut *mut IDWriteNumberSubstitution,
+) -> HRESULT {
+    let this = CustomTextAnalysisSourceImpl::from_interface(this);
+    if text_position >= (this.text.len() as u32) {
+        return E_INVALIDARG;
+    }
+
+    *text_length = (this.text.len() as UINT32) - text_position;
+    *number_substitution = match &this.number_subst {
+        Some(number_subst) => {
+            let com_ptr = &number_subst.native;
+            com_ptr.AddRef();
+            com_ptr.as_raw()
+        },
+        None => std::ptr::null_mut()
+    };
+
+    S_OK
+}
+
+unsafe extern "system" fn CustomTextAnalysisSourceImpl_GetParagraphReadingDirection(
+    this: *mut IDWriteTextAnalysisSource,
+) -> DWRITE_READING_DIRECTION {
+    let this = CustomTextAnalysisSourceImpl::from_interface(this);
+    this.inner.get_paragraph_reading_direction()
+}
+
+unsafe extern "system" fn CustomTextAnalysisSourceImpl_GetTextAtPosition(
+    this: *mut IDWriteTextAnalysisSource,
+    text_position: UINT32,
+    text_string: *mut *const wchar_t,
+    text_length: *mut UINT32,
+) -> HRESULT {
+    let this = CustomTextAnalysisSourceImpl::from_interface(this);
+    if text_position >= (this.text.len() as u32) {
+        *text_string = null();
+        *text_length = 0;
+        return S_OK;
+    }
+    *text_string = this.text.as_ptr().add(text_position as usize);
+    *text_length = (this.text.len() as UINT32) - text_position;
+    S_OK
+}
+
+unsafe extern "system" fn CustomTextAnalysisSourceImpl_GetTextBeforePosition(
+    this: *mut IDWriteTextAnalysisSource,
+    text_position: UINT32,
+    text_string: *mut *const wchar_t,
+    text_length: *mut UINT32,
+) -> HRESULT {
+    let this = CustomTextAnalysisSourceImpl::from_interface(this);
+    if text_position == 0 || text_position > (this.text.len() as u32) {
+        *text_string = null();
+        *text_length = 0;
+        return S_OK;
+    }
+    *text_string = this.text.as_ptr();
+    *text_length = text_position;
+    S_OK
+}
+
+impl NumberSubstitution {
+    pub fn new(
+        subst_method: DWRITE_NUMBER_SUBSTITUTION_METHOD,
+        locale: &str,
+        ignore_user_overrides: bool,
+    ) -> NumberSubstitution {
+        unsafe {
+            let mut native: *mut IDWriteNumberSubstitution = ptr::null_mut();
+            let hr = (*DWriteFactory()).CreateNumberSubstitution(
+                subst_method,
+                locale.to_wide_null().as_ptr(),
+                if ignore_user_overrides { TRUE } else { FALSE },
+                &mut native,
+            );
+            assert_eq!(hr, 0, "error creating number substitution");
+            NumberSubstitution {
+                native: ComPtr::from_raw(native),
+            }
+        }
+    }
+}
diff --git a/third_party/rust/dwrote/src/types.rs b/third_party/rust/dwrote/src/types.rs
new file mode 100644
index 0000000000..d488a0805e
--- /dev/null
+++ b/third_party/rust/dwrote/src/types.rs
@@ -0,0 +1,126 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* this is include!()'d in lib.rs */
+use std::mem;
+use winapi::um::dwrite::{DWRITE_FONT_STYLE, DWRITE_FONT_WEIGHT, DWRITE_FONT_STRETCH};
+
+// mirrors DWRITE_FONT_WEIGHT
+#[cfg_attr(feature = "serde_serialization", derive(Deserialize, Serialize))]
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub enum FontWeight {
+    Thin,
+    ExtraLight,
+    Light,
+    SemiLight,
+    Regular,
+    Medium,
+    SemiBold,
+    Bold,
+    ExtraBold,
+    Black,
+    ExtraBlack,
+    Unknown(u32)
+}
+
+impl FontWeight {
+    fn t(&self) -> DWRITE_FONT_WEIGHT {
+        unsafe { mem::transmute::<u32, DWRITE_FONT_WEIGHT>(self.to_u32()) }
+    }
+    pub fn to_u32(&self) -> u32 {
+        match self {
+            FontWeight::Thin=> 100,
+            FontWeight::ExtraLight=> 200,
+            FontWeight::Light=> 300,
+            FontWeight::SemiLight=> 350,
+            FontWeight::Regular=> 400,
+            FontWeight::Medium=> 500,
+            FontWeight::SemiBold=> 600,
+            FontWeight::Bold=> 700,
+            FontWeight::ExtraBold=> 800,
+            FontWeight::Black=> 900,
+            FontWeight::ExtraBlack=> 950,
+            FontWeight::Unknown(v) => *v as u32
+        }
+    }
+    pub fn from_u32(v: u32) -> FontWeight {
+        match v {
+                100 => FontWeight::Thin,
+                200 => FontWeight::ExtraLight,
+                300 => FontWeight::Light,
+                350 => FontWeight::SemiLight,
+                400 => FontWeight::Regular,
+                500 => FontWeight::Medium,
+                600 => FontWeight::SemiBold,
+                700 => FontWeight::Bold,
+                800 => FontWeight::ExtraBold,
+                900 => FontWeight::Black,
+                950 => FontWeight::ExtraBlack,
+                _ => FontWeight::Unknown(v)
+            }
+    }
+}
+
+// mirrors DWRITE_FONT_STRETCH
+#[repr(u32)]
+#[cfg_attr(feature = "serde_serialization", derive(Deserialize, Serialize))]
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub enum FontStretch {
+    Undefined = 0,
+    UltraCondensed = 1,
+    ExtraCondensed = 2,
+    Condensed = 3,
+    SemiCondensed = 4,
+    Normal = 5,
+    SemiExpanded = 6,
+    Expanded = 7,
+    ExtraExpanded = 8,
+    UltraExpanded = 9,
+}
+
+impl FontStretch {
+    fn t(&self) -> DWRITE_FONT_STRETCH {
+        unsafe { mem::transmute::<FontStretch, DWRITE_FONT_STRETCH>(*self) }
+    }
+    pub fn to_u32(&self) -> u32 { unsafe { mem::transmute::<FontStretch, u32>(*self) } }
+    pub fn from_u32(v: u32) -> FontStretch { unsafe { mem::transmute::<u32, FontStretch>(v) } }
+}
+
+// mirrors DWRITE_FONT_STYLE
+#[repr(u32)]
+#[cfg_attr(feature = "serde_serialization", derive(Deserialize, Serialize))]
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub enum FontStyle {
+    Normal = 0,
+    Oblique = 1,
+    Italic = 2,
+}
+
+impl FontStyle {
+    fn t(&self) -> DWRITE_FONT_STYLE {
+        unsafe { mem::transmute::<FontStyle, DWRITE_FONT_STYLE>(*self) }
+    }
+    pub fn to_u32(&self) -> u32 { unsafe { mem::transmute::<FontStyle, u32>(*self) } }
+    pub fn from_u32(v: u32) -> FontStyle { unsafe { mem::transmute::<u32, FontStyle>(v) } }
+}
+
+// mirrors DWRITE_FONT_SIMULATIONS
+#[repr(u32)]
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub enum FontSimulations {
+    None = winapi::um::dwrite::DWRITE_FONT_SIMULATIONS_NONE,
+    Bold = winapi::um::dwrite::DWRITE_FONT_SIMULATIONS_BOLD,
+    Oblique = winapi::um::dwrite::DWRITE_FONT_SIMULATIONS_OBLIQUE,
+    BoldOblique = winapi::um::dwrite::DWRITE_FONT_SIMULATIONS_BOLD |
+        winapi::um::dwrite::DWRITE_FONT_SIMULATIONS_OBLIQUE,
+}
+
+#[cfg_attr(feature = "serde_serialization", derive(Deserialize, Serialize))]
+#[derive(PartialEq, Debug, Clone)]
+pub struct FontDescriptor {
+    pub family_name: String,
+    pub weight: FontWeight,
+    pub stretch: FontStretch,
+    pub style: FontStyle,
+}