diff options
Diffstat (limited to 'gfx/wr/webrender/src/platform/windows/font.rs')
| -rw-r--r-- | gfx/wr/webrender/src/platform/windows/font.rs | 603 |
1 files changed, 603 insertions, 0 deletions
diff --git a/gfx/wr/webrender/src/platform/windows/font.rs b/gfx/wr/webrender/src/platform/windows/font.rs new file mode 100644 index 0000000000..49ec039017 --- /dev/null +++ b/gfx/wr/webrender/src/platform/windows/font.rs @@ -0,0 +1,603 @@ +/* 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 api::{FontInstanceFlags, FontKey, FontRenderMode, FontVariation}; +use api::{ColorU, GlyphDimensions, NativeFontHandle}; +use dwrote; +use crate::gamma_lut::ColorLut; +use crate::glyph_rasterizer::{FontInstance, FontTransform, GlyphKey}; +use crate::internal_types::{FastHashMap, FastHashSet, ResourceCacheError}; +use crate::glyph_rasterizer::{GlyphFormat, GlyphRasterError, GlyphRasterResult, RasterizedGlyph}; +use crate::gamma_lut::GammaLut; +use std::borrow::Borrow; +use std::collections::hash_map::Entry; +use std::hash::{Hash, Hasher}; +use std::path::Path; +use std::sync::{Arc, Mutex}; +use api::FontInstancePlatformOptions; +use std::mem; + +lazy_static! { + static ref DEFAULT_FONT_DESCRIPTOR: dwrote::FontDescriptor = dwrote::FontDescriptor { + family_name: "Arial".to_owned(), + weight: dwrote::FontWeight::Regular, + stretch: dwrote::FontStretch::Normal, + style: dwrote::FontStyle::Normal, + }; +} + +type CachedFontKey = Arc<Path>; + +// A cached dwrote font file that is shared among all faces. +// Each face holds a CachedFontKey to keep track of how many users of the font there are. +struct CachedFont { + key: CachedFontKey, + file: dwrote::FontFile, +} + +// FontFile contains a ComPtr<IDWriteFontFile>, but DWrite font files are threadsafe. +unsafe impl Send for CachedFont {} + +impl PartialEq for CachedFont { + fn eq(&self, other: &CachedFont) -> bool { + self.key == other.key + } +} +impl Eq for CachedFont {} + +impl Hash for CachedFont { + fn hash<H: Hasher>(&self, state: &mut H) { + self.key.hash(state); + } +} + +impl Borrow<Path> for CachedFont { + fn borrow(&self) -> &Path { + &*self.key + } +} + +lazy_static! { + // This is effectively a weak map of dwrote FontFiles. CachedFonts are entered into the + // cache when there are any FontFaces using them. CachedFonts are removed from the cache + // when there are no more FontFaces using them at all. + static ref FONT_CACHE: Mutex<FastHashSet<CachedFont>> = Mutex::new(FastHashSet::default()); +} + +struct FontFace { + cached: Option<CachedFontKey>, + file: dwrote::FontFile, + index: u32, + face: dwrote::FontFace, +} + +pub struct FontContext { + fonts: FastHashMap<FontKey, FontFace>, + variations: FastHashMap<(FontKey, dwrote::DWRITE_FONT_SIMULATIONS, Vec<FontVariation>), dwrote::FontFace>, + gamma_luts: FastHashMap<(u16, u8), GammaLut>, +} + +// DirectWrite is safe to use on multiple threads and non-shareable resources are +// all hidden inside their font context. +unsafe impl Send for FontContext {} + +fn dwrite_texture_type(render_mode: FontRenderMode) -> dwrote::DWRITE_TEXTURE_TYPE { + match render_mode { + FontRenderMode::Mono => dwrote::DWRITE_TEXTURE_ALIASED_1x1, + FontRenderMode::Alpha | + FontRenderMode::Subpixel => dwrote::DWRITE_TEXTURE_CLEARTYPE_3x1, + } +} + +fn dwrite_measure_mode( + font: &FontInstance, + bitmaps: bool, +) -> dwrote::DWRITE_MEASURING_MODE { + if bitmaps || font.flags.contains(FontInstanceFlags::FORCE_GDI) { + dwrote::DWRITE_MEASURING_MODE_GDI_CLASSIC + } else { + match font.render_mode { + FontRenderMode::Mono => dwrote::DWRITE_MEASURING_MODE_GDI_CLASSIC, + FontRenderMode::Alpha | FontRenderMode::Subpixel => dwrote::DWRITE_MEASURING_MODE_NATURAL, + } + } +} + +fn dwrite_render_mode( + font_face: &dwrote::FontFace, + font: &FontInstance, + em_size: f32, + measure_mode: dwrote::DWRITE_MEASURING_MODE, + bitmaps: bool, +) -> dwrote::DWRITE_RENDERING_MODE { + let dwrite_render_mode = match font.render_mode { + FontRenderMode::Mono => dwrote::DWRITE_RENDERING_MODE_ALIASED, + FontRenderMode::Alpha | FontRenderMode::Subpixel => { + if bitmaps || font.flags.contains(FontInstanceFlags::FORCE_GDI) { + dwrote::DWRITE_RENDERING_MODE_GDI_CLASSIC + } else if font.flags.contains(FontInstanceFlags::FORCE_SYMMETRIC) { + dwrote::DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC + } else if font.flags.contains(FontInstanceFlags::NO_SYMMETRIC) { + dwrote::DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL + } else { + font_face.get_recommended_rendering_mode_default_params(em_size, 1.0, measure_mode) + } + } + }; + + if dwrite_render_mode == dwrote::DWRITE_RENDERING_MODE_OUTLINE { + // Outline mode is not supported + return dwrote::DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC; + } + + dwrite_render_mode +} + +fn is_bitmap_font(font: &FontInstance) -> bool { + // If bitmaps are requested, then treat as a bitmap font to disable transforms. + // If mono AA is requested, let that take priority over using bitmaps. + font.render_mode != FontRenderMode::Mono && + font.flags.contains(FontInstanceFlags::EMBEDDED_BITMAPS) +} + +impl FontContext { + pub fn new() -> Result<FontContext, ResourceCacheError> { + Ok(FontContext { + fonts: FastHashMap::default(), + variations: FastHashMap::default(), + gamma_luts: FastHashMap::default(), + }) + } + + pub fn has_font(&self, font_key: &FontKey) -> bool { + self.fonts.contains_key(font_key) + } + + fn add_font_descriptor(&mut self, font_key: &FontKey, desc: &dwrote::FontDescriptor) { + let system_fc = dwrote::FontCollection::get_system(false); + if let Some(font) = system_fc.get_font_from_descriptor(desc) { + let face = font.create_font_face(); + let file = face.get_files().pop().unwrap(); + let index = face.get_index(); + self.fonts.insert(*font_key, FontFace { cached: None, file, index, face }); + } + } + + pub fn add_raw_font(&mut self, font_key: &FontKey, data: Arc<Vec<u8>>, index: u32) { + if self.fonts.contains_key(font_key) { + return; + } + + if let Some(file) = dwrote::FontFile::new_from_data(data) { + if let Ok(face) = file.create_face(index, dwrote::DWRITE_FONT_SIMULATIONS_NONE) { + self.fonts.insert(*font_key, FontFace { cached: None, file, index, face }); + return; + } + } + // XXX add_raw_font needs to have a way to return an error + debug!("DWrite WR failed to load font from data, using Arial instead"); + self.add_font_descriptor(font_key, &DEFAULT_FONT_DESCRIPTOR); + } + + pub fn add_native_font(&mut self, font_key: &FontKey, font_handle: NativeFontHandle) { + if self.fonts.contains_key(font_key) { + return; + } + + let index = font_handle.index; + let mut cache = FONT_CACHE.lock().unwrap(); + // Check to see if the font is already in the cache. If so, reuse it. + if let Some(font) = cache.get(font_handle.path.as_path()) { + if let Ok(face) = font.file.create_face(index, dwrote::DWRITE_FONT_SIMULATIONS_NONE) { + self.fonts.insert( + *font_key, + FontFace { cached: Some(font.key.clone()), file: font.file.clone(), index, face }, + ); + return; + } + } + if let Some(file) = dwrote::FontFile::new_from_path(&font_handle.path) { + // The font is not in the cache yet, so try to create the font and insert it in the cache. + if let Ok(face) = file.create_face(index, dwrote::DWRITE_FONT_SIMULATIONS_NONE) { + let key: CachedFontKey = font_handle.path.into(); + self.fonts.insert( + *font_key, + FontFace { cached: Some(key.clone()), file: file.clone(), index, face }, + ); + cache.insert(CachedFont { key, file }); + return; + } + } + + // XXX add_native_font needs to have a way to return an error + debug!("DWrite WR failed to load font from path, using Arial instead"); + self.add_font_descriptor(font_key, &DEFAULT_FONT_DESCRIPTOR); + } + + pub fn delete_font(&mut self, font_key: &FontKey) { + if let Some(face) = self.fonts.remove(font_key) { + self.variations.retain(|k, _| k.0 != *font_key); + // Check if this was a cached font. + if let Some(key) = face.cached { + let mut cache = FONT_CACHE.lock().unwrap(); + // If there are only two references left, that means only this face and + // the cache are using the font. So remove it from the cache. + if Arc::strong_count(&key) == 2 { + cache.remove(&*key); + } + } + } + } + + pub fn delete_font_instance(&mut self, instance: &FontInstance) { + // Ensure we don't keep around excessive amounts of stale variations. + if !instance.variations.is_empty() { + let sims = if instance.flags.contains(FontInstanceFlags::SYNTHETIC_BOLD) { + dwrote::DWRITE_FONT_SIMULATIONS_BOLD + } else { + dwrote::DWRITE_FONT_SIMULATIONS_NONE + }; + self.variations.remove(&(instance.font_key, sims, instance.variations.clone())); + } + } + + // Assumes RGB format from dwrite, which is 3 bytes per pixel as dwrite + // doesn't output an alpha value via GlyphRunAnalysis::CreateAlphaTexture + #[allow(dead_code)] + fn print_glyph_data(&self, data: &[u8], width: usize, height: usize) { + // Rust doesn't have step_by support on stable :( + for i in 0 .. height { + let current_height = i * width * 3; + + for pixel in data[current_height .. current_height + (width * 3)].chunks(3) { + let r = pixel[0]; + let g = pixel[1]; + let b = pixel[2]; + print!("({}, {}, {}) ", r, g, b,); + } + println!(); + } + } + + fn get_font_face( + &mut self, + font: &FontInstance, + ) -> &dwrote::FontFace { + if !font.flags.contains(FontInstanceFlags::SYNTHETIC_BOLD) && + font.variations.is_empty() { + return &self.fonts.get(&font.font_key).unwrap().face; + } + let sims = if font.flags.contains(FontInstanceFlags::SYNTHETIC_BOLD) { + dwrote::DWRITE_FONT_SIMULATIONS_BOLD + } else { + dwrote::DWRITE_FONT_SIMULATIONS_NONE + }; + match self.variations.entry((font.font_key, sims, font.variations.clone())) { + Entry::Occupied(entry) => entry.into_mut(), + Entry::Vacant(entry) => { + let normal_face = self.fonts.get(&font.font_key).unwrap(); + if !font.variations.is_empty() { + if let Some(var_face) = normal_face.face.create_font_face_with_variations( + sims, + &font.variations.iter().map(|var| { + dwrote::DWRITE_FONT_AXIS_VALUE { + // OpenType tags are big-endian, but DWrite wants little-endian. + axisTag: var.tag.swap_bytes(), + value: var.value, + } + }).collect::<Vec<_>>(), + ) { + return entry.insert(var_face); + } + } + let var_face = normal_face.file + .create_face(normal_face.index, sims) + .unwrap_or_else(|_| normal_face.face.clone()); + entry.insert(var_face) + } + } + } + + fn create_glyph_analysis( + &mut self, + font: &FontInstance, + key: &GlyphKey, + size: f32, + transform: Option<dwrote::DWRITE_MATRIX>, + bitmaps: bool, + ) -> Result<(dwrote::GlyphRunAnalysis, dwrote::DWRITE_TEXTURE_TYPE, dwrote::RECT), dwrote::HRESULT> { + let face = self.get_font_face(font); + let glyph = key.index() as u16; + let advance = 0.0f32; + let offset = dwrote::GlyphOffset { + advanceOffset: 0.0, + ascenderOffset: 0.0, + }; + + let glyph_run = dwrote::DWRITE_GLYPH_RUN { + fontFace: unsafe { face.as_ptr() }, + fontEmSize: size, // size in DIPs (1/96", same as CSS pixels) + glyphCount: 1, + glyphIndices: &glyph, + glyphAdvances: &advance, + glyphOffsets: &offset, + isSideways: 0, + bidiLevel: 0, + }; + + let dwrite_measure_mode = dwrite_measure_mode(font, bitmaps); + let dwrite_render_mode = dwrite_render_mode( + face, + font, + size, + dwrite_measure_mode, + bitmaps, + ); + + let analysis = dwrote::GlyphRunAnalysis::create( + &glyph_run, + 1.0, + transform, + dwrite_render_mode, + dwrite_measure_mode, + 0.0, + 0.0, + )?; + let texture_type = dwrite_texture_type(font.render_mode); + let bounds = analysis.get_alpha_texture_bounds(texture_type)?; + // If the bounds are empty, then we might not be able to render the glyph with cleartype. + // Try again with aliased rendering to check if that works instead. + if font.render_mode != FontRenderMode::Mono && + (bounds.left == bounds.right || bounds.top == bounds.bottom) { + let analysis2 = dwrote::GlyphRunAnalysis::create( + &glyph_run, + 1.0, + transform, + dwrote::DWRITE_RENDERING_MODE_ALIASED, + dwrite_measure_mode, + 0.0, + 0.0, + )?; + let bounds2 = analysis2.get_alpha_texture_bounds(dwrote::DWRITE_TEXTURE_ALIASED_1x1)?; + if bounds2.left != bounds2.right && bounds2.top != bounds2.bottom { + return Ok((analysis2, dwrote::DWRITE_TEXTURE_ALIASED_1x1, bounds2)); + } + } + Ok((analysis, texture_type, bounds)) + } + + pub fn get_glyph_index(&mut self, font_key: FontKey, ch: char) -> Option<u32> { + let face = &self.fonts.get(&font_key).unwrap().face; + let indices = face.get_glyph_indices(&[ch as u32]); + indices.first().map(|idx| *idx as u32) + } + + pub fn get_glyph_dimensions( + &mut self, + font: &FontInstance, + key: &GlyphKey, + ) -> Option<GlyphDimensions> { + let (size, _, bitmaps, transform) = Self::get_glyph_parameters(font, key); + let (_, _, bounds) = self.create_glyph_analysis(font, key, size, transform, bitmaps).ok()?; + + let width = (bounds.right - bounds.left) as i32; + let height = (bounds.bottom - bounds.top) as i32; + + // Alpha texture bounds can sometimes return an empty rect + // Such as for spaces + if width == 0 || height == 0 { + return None; + } + + let face = self.get_font_face(font); + face.get_design_glyph_metrics(&[key.index() as u16], false) + .first() + .map(|metrics| { + let em_size = size / 16.; + let design_units_per_pixel = face.metrics().metrics0().designUnitsPerEm as f32 / 16. as f32; + let scaled_design_units_to_pixels = em_size / design_units_per_pixel; + let advance = metrics.advanceWidth as f32 * scaled_design_units_to_pixels; + + GlyphDimensions { + left: bounds.left, + top: -bounds.top, + width, + height, + advance, + } + }) + } + + // DWrite ClearType gives us values in RGB, but WR expects BGRA. + fn convert_to_bgra( + &self, + pixels: &[u8], + width: usize, + height: usize, + texture_type: dwrote::DWRITE_TEXTURE_TYPE, + render_mode: FontRenderMode, + bitmaps: bool, + subpixel_bgr: bool, + texture_padding: bool, + ) -> Vec<u8> { + let (buffer_width, buffer_height, padding) = if texture_padding { + (width + 2, height + 2, 1) + } else { + (width, height, 0) + }; + + let buffer_length = buffer_width * buffer_height * 4; + let mut bgra_pixels: Vec<u8> = vec![0; buffer_length]; + + match (texture_type, render_mode, bitmaps) { + (dwrote::DWRITE_TEXTURE_ALIASED_1x1, _, _) => { + assert!(width * height == pixels.len()); + let mut i = 0; + for row in padding .. height + padding { + let row_offset = row * buffer_width; + for col in padding .. width + padding { + let offset = (row_offset + col) * 4; + let alpha = pixels[i]; + i += 1; + bgra_pixels[offset + 0] = alpha; + bgra_pixels[offset + 1] = alpha; + bgra_pixels[offset + 2] = alpha; + bgra_pixels[offset + 3] = alpha; + } + } + } + (_, FontRenderMode::Subpixel, false) => { + assert!(width * height * 3 == pixels.len()); + let mut i = 0; + for row in padding .. height + padding { + let row_offset = row * buffer_width; + for col in padding .. width + padding { + let offset = (row_offset + col) * 4; + let (mut r, g, mut b) = (pixels[i + 0], pixels[i + 1], pixels[i + 2]); + if subpixel_bgr { + mem::swap(&mut r, &mut b); + } + i += 3; + bgra_pixels[offset + 0] = b; + bgra_pixels[offset + 1] = g; + bgra_pixels[offset + 2] = r; + bgra_pixels[offset + 3] = 0xff; + } + } + } + _ => { + assert!(width * height * 3 == pixels.len()); + let mut i = 0; + for row in padding .. height + padding { + let row_offset = row * buffer_width; + for col in padding .. width + padding { + let offset = (row_offset + col) * 4; + // Only take the G channel, as its closest to D2D + let alpha = pixels[i + 1] as u8; + i += 3; + bgra_pixels[offset + 0] = alpha; + bgra_pixels[offset + 1] = alpha; + bgra_pixels[offset + 2] = alpha; + bgra_pixels[offset + 3] = alpha; + } + } + } + }; + bgra_pixels + } + + pub fn prepare_font(font: &mut FontInstance) { + match font.render_mode { + FontRenderMode::Mono => { + // In mono mode the color of the font is irrelevant. + font.color = ColorU::new(255, 255, 255, 255); + // Subpixel positioning is disabled in mono mode. + font.disable_subpixel_position(); + } + FontRenderMode::Alpha => { + font.color = font.color.luminance_color().quantize(); + } + FontRenderMode::Subpixel => { + font.color = font.color.quantize(); + } + } + } + + fn get_glyph_parameters(font: &FontInstance, key: &GlyphKey) -> (f32, f64, bool, Option<dwrote::DWRITE_MATRIX>) { + let (_, y_scale) = font.transform.compute_scale().unwrap_or((1.0, 1.0)); + let scaled_size = font.size.to_f64_px() * y_scale; + let bitmaps = is_bitmap_font(font); + let (mut shape, (mut x_offset, mut y_offset)) = if bitmaps { + (FontTransform::identity(), (0.0, 0.0)) + } else { + (font.transform.invert_scale(y_scale, y_scale), font.get_subpx_offset(key)) + }; + if font.flags.contains(FontInstanceFlags::FLIP_X) { + shape = shape.flip_x(); + } + if font.flags.contains(FontInstanceFlags::FLIP_Y) { + shape = shape.flip_y(); + } + if font.flags.contains(FontInstanceFlags::TRANSPOSE) { + shape = shape.swap_xy(); + } + let (mut tx, mut ty) = (0.0, 0.0); + if font.synthetic_italics.is_enabled() { + let (shape_, (tx_, ty_)) = font.synthesize_italics(shape, scaled_size); + shape = shape_; + tx = tx_; + ty = ty_; + }; + x_offset += tx; + y_offset += ty; + let transform = if !shape.is_identity() || (x_offset, y_offset) != (0.0, 0.0) { + Some(dwrote::DWRITE_MATRIX { + m11: shape.scale_x, + m12: shape.skew_y, + m21: shape.skew_x, + m22: shape.scale_y, + dx: x_offset as f32, + dy: y_offset as f32, + }) + } else { + None + }; + (scaled_size as f32, y_scale, bitmaps, transform) + } + + pub fn rasterize_glyph(&mut self, font: &FontInstance, key: &GlyphKey) -> GlyphRasterResult { + let (size, y_scale, bitmaps, transform) = Self::get_glyph_parameters(font, key); + let (analysis, texture_type, bounds) = self.create_glyph_analysis(font, key, size, transform, bitmaps) + .or(Err(GlyphRasterError::LoadFailed))?; + let width = (bounds.right - bounds.left) as i32; + let height = (bounds.bottom - bounds.top) as i32; + // Alpha texture bounds can sometimes return an empty rect + // Such as for spaces + if width == 0 || height == 0 { + return Err(GlyphRasterError::LoadFailed); + } + + let pixels = analysis.create_alpha_texture(texture_type, bounds).or(Err(GlyphRasterError::LoadFailed))?; + let mut bgra_pixels = self.convert_to_bgra(&pixels, width as usize, height as usize, + texture_type, font.render_mode, bitmaps, + font.flags.contains(FontInstanceFlags::SUBPIXEL_BGR), + font.use_texture_padding()); + + let FontInstancePlatformOptions { gamma, contrast, cleartype_level, .. } = + font.platform_options.unwrap_or_default(); + let gamma_lut = self.gamma_luts + .entry((gamma, contrast)) + .or_insert_with(|| + GammaLut::new( + contrast as f32 / 100.0, + gamma as f32 / 100.0, + gamma as f32 / 100.0, + )); + if bitmaps || texture_type == dwrote::DWRITE_TEXTURE_ALIASED_1x1 || + font.render_mode != FontRenderMode::Subpixel { + gamma_lut.preblend(&mut bgra_pixels, font.color); + } else { + gamma_lut.preblend_scaled(&mut bgra_pixels, font.color, cleartype_level); + } + + let format = if bitmaps { + GlyphFormat::Bitmap + } else if texture_type == dwrote::DWRITE_TEXTURE_ALIASED_1x1 { + font.get_alpha_glyph_format() + } else { + font.get_glyph_format() + }; + + let padding = if font.use_texture_padding() { 1 } else { 0 }; + Ok(RasterizedGlyph { + left: (bounds.left - padding) as f32, + top: (-bounds.top + padding) as f32, + width: width + padding * 2, + height: height + padding * 2, + scale: (if bitmaps { y_scale.recip() } else { 1.0 }) as f32, + format, + bytes: bgra_pixels, + }) + } +} |