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Diffstat (limited to 'gfx/wr/webrender/src/glyph_rasterizer/mod.rs')
-rw-r--r-- | gfx/wr/webrender/src/glyph_rasterizer/mod.rs | 1338 |
1 files changed, 1338 insertions, 0 deletions
diff --git a/gfx/wr/webrender/src/glyph_rasterizer/mod.rs b/gfx/wr/webrender/src/glyph_rasterizer/mod.rs new file mode 100644 index 0000000000..98aa9e23d9 --- /dev/null +++ b/gfx/wr/webrender/src/glyph_rasterizer/mod.rs @@ -0,0 +1,1338 @@ +/* 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, FontSize, BaseFontInstance}; +use api::{FontKey, FontRenderMode, FontTemplate}; +use api::{ColorU, GlyphIndex, GlyphDimensions, SyntheticItalics}; +use api::channel::{unbounded_channel, Receiver, Sender}; +use api::units::*; +use api::{ImageDescriptor, ImageDescriptorFlags, ImageFormat, DirtyRect}; +use crate::internal_types::ResourceCacheError; +use crate::platform::font::FontContext; +use crate::device::TextureFilter; +use crate::gpu_types::UvRectKind; +use crate::glyph_cache::{GlyphCache, CachedGlyphInfo, GlyphCacheEntry}; +use crate::internal_types::FastHashMap; +use crate::resource_cache::CachedImageData; +use crate::texture_cache::{TextureCache, TextureCacheHandle, Eviction, TargetShader}; +use crate::gpu_cache::GpuCache; +use crate::profiler::{self, TransactionProfile}; +use malloc_size_of::{MallocSizeOf, MallocSizeOfOps}; +use rayon::ThreadPool; +use rayon::prelude::*; +use euclid::approxeq::ApproxEq; +use euclid::size2; +use smallvec::SmallVec; +use std::cmp; +use std::cell::Cell; +use std::hash::{Hash, Hasher}; +use std::mem; +use std::ops::Deref; +use std::sync::{Arc, Condvar, Mutex, MutexGuard}; +use std::sync::atomic::{AtomicBool, Ordering}; + +pub static GLYPH_FLASHING: AtomicBool = AtomicBool::new(false); + +impl FontContexts { + /// Get access to the font context associated to the current thread. + pub fn lock_current_context(&self) -> MutexGuard<FontContext> { + let id = self.current_worker_id(); + self.lock_context(id) + } + + pub(in super) fn current_worker_id(&self) -> Option<usize> { + self.workers.current_thread_index() + } +} + +thread_local! { + pub static SEED: Cell<u32> = Cell::new(0); +} + +// super simple random to avoid dependency on rand +fn random() -> u32 { + SEED.with(|seed| { + seed.set(seed.get().wrapping_mul(22695477).wrapping_add(1)); + seed.get() + }) +} + +impl GlyphRasterizer { + pub fn request_glyphs( + &mut self, + glyph_cache: &mut GlyphCache, + font: FontInstance, + glyph_keys: &[GlyphKey], + texture_cache: &mut TextureCache, + gpu_cache: &mut GpuCache, + ) { + assert!( + self.font_contexts + .lock_shared_context() + .has_font(&font.font_key) + ); + + let glyph_key_cache = glyph_cache.get_glyph_key_cache_for_font_mut(font.clone()); + + // select glyphs that have not been requested yet. + for key in glyph_keys { + if let Some(entry) = glyph_key_cache.try_get(key) { + match entry { + GlyphCacheEntry::Cached(ref glyph) => { + // Skip the glyph if it is already has a valid texture cache handle. + if !texture_cache.request(&glyph.texture_cache_handle, gpu_cache) { + continue; + } + // This case gets hit when we already rasterized the glyph, but the + // glyph has been evicted from the texture cache. Just force it to + // pending so it gets rematerialized. + } + // Otherwise, skip the entry if it is blank or pending. + GlyphCacheEntry::Blank | GlyphCacheEntry::Pending => continue, + } + } + + // Increment the total number of glyphs that are pending. This is used to determine + // later whether to use worker threads for the remaining glyphs during resolve time. + self.pending_glyph_count += 1; + self.glyph_request_count += 1; + + // Find a batch container for the font instance for this glyph. Use get_mut to avoid + // cloning the font instance, since this is the common path. + match self.pending_glyph_requests.get_mut(&font) { + Some(container) => { + container.push(*key); + + // If the batch for this font instance is big enough, kick off an async + // job to start rasterizing these glyphs on other threads now. + if container.len() == 8 { + let glyphs = mem::replace(container, SmallVec::new()); + self.flush_glyph_requests( + font.clone(), + glyphs, + true, + ); + } + } + None => { + // If no batch exists for this font instance, add the glyph to a new one. + self.pending_glyph_requests.insert( + font.clone(), + smallvec![*key], + ); + } + } + + glyph_key_cache.add_glyph(*key, GlyphCacheEntry::Pending); + } + } + + pub fn enable_multithreading(&mut self, enable: bool) { + self.enable_multithreading = enable; + } + + /// Internal method to flush a list of glyph requests to a set of worker threads, + /// or process on this thread if there isn't much work to do (in which case the + /// overhead of processing these on a thread is unlikely to be a performance win). + fn flush_glyph_requests( + &mut self, + font: FontInstance, + glyphs: SmallVec<[GlyphKey; 16]>, + use_workers: bool, + ) { + let font_contexts = Arc::clone(&self.font_contexts); + let glyph_tx = self.glyph_tx.clone(); + self.pending_glyph_jobs += 1; + self.pending_glyph_count -= glyphs.len(); + + fn process_glyph(key: &GlyphKey, font_contexts: &FontContexts, font: &FontInstance) -> GlyphRasterJob { + profile_scope!("glyph-raster"); + let mut context = font_contexts.lock_current_context(); + let mut job = GlyphRasterJob { + key: key.clone(), + result: context.rasterize_glyph(&font, key), + }; + + if let Ok(ref mut glyph) = job.result { + // Sanity check. + let bpp = 4; // We always render glyphs in 32 bits RGBA format. + assert_eq!( + glyph.bytes.len(), + bpp * (glyph.width * glyph.height) as usize + ); + + // a quick-and-dirty monochrome over + fn over(dst: u8, src: u8) -> u8 { + let a = src as u32; + let a = 256 - a; + let dst = ((dst as u32 * a) >> 8) as u8; + src + dst + } + + if GLYPH_FLASHING.load(Ordering::Relaxed) { + let color = (random() & 0xff) as u8; + for i in &mut glyph.bytes { + *i = over(*i, color); + } + } + + assert_eq!((glyph.left.fract(), glyph.top.fract()), (0.0, 0.0)); + + // Check if the glyph has a bitmap that needs to be downscaled. + glyph.downscale_bitmap_if_required(&font); + + // Convert from BGRA8 to R8 if required. In the future we can make it the + // backends' responsibility to output glyphs in the desired format, + // potentially reducing the number of copies. + if glyph.format.image_format().bytes_per_pixel() == 1 { + glyph.bytes = glyph.bytes + .chunks_mut(4) + .map(|pixel| pixel[3]) + .collect::<Vec<_>>(); + } + } + + job + } + + // if the number of glyphs is small, do it inline to avoid the threading overhead; + // send the result into glyph_tx so downstream code can't tell the difference. + if self.enable_multithreading && use_workers { + // spawn an async task to get off of the render backend thread as early as + // possible and in that task use rayon's fork join dispatch to rasterize the + // glyphs in the thread pool. + profile_scope!("spawning process_glyph jobs"); + self.workers.spawn(move || { + let jobs = glyphs + .par_iter() + .map(|key: &GlyphKey| process_glyph(key, &font_contexts, &font)) + .collect(); + + glyph_tx.send(GlyphRasterJobs { font, jobs }).unwrap(); + }); + } else { + let jobs = glyphs.iter() + .map(|key: &GlyphKey| process_glyph(key, &font_contexts, &font)) + .collect(); + glyph_tx.send(GlyphRasterJobs { font, jobs }).unwrap(); + } + } + + pub fn resolve_glyphs( + &mut self, + glyph_cache: &mut GlyphCache, + texture_cache: &mut TextureCache, + gpu_cache: &mut GpuCache, + profile: &mut TransactionProfile, + ) { + profile.start_time(profiler::GLYPH_RESOLVE_TIME); + + // Work around the borrow checker, since we call flush_glyph_requests below + let mut pending_glyph_requests = mem::replace( + &mut self.pending_glyph_requests, + FastHashMap::default(), + ); + // If we have a large amount of remaining work to do, spawn to worker threads, + // even if that work is shared among a number of different font instances. + let use_workers = self.pending_glyph_count >= 8; + for (font, pending_glyphs) in pending_glyph_requests.drain() { + self.flush_glyph_requests( + font, + pending_glyphs, + use_workers, + ); + } + // Restore this so that we don't heap allocate next frame + self.pending_glyph_requests = pending_glyph_requests; + debug_assert_eq!(self.pending_glyph_count, 0); + debug_assert!(self.pending_glyph_requests.is_empty()); + + if self.glyph_request_count > 0 { + profile.set(profiler::RASTERIZED_GLYPHS, self.glyph_request_count); + self.glyph_request_count = 0; + } + + profile_scope!("resolve_glyphs"); + // Pull rasterized glyphs from the queue and update the caches. + while self.pending_glyph_jobs > 0 { + self.pending_glyph_jobs -= 1; + + // TODO: rather than blocking until all pending glyphs are available + // we could try_recv and steal work from the thread pool to take advantage + // of the fact that this thread is alive and we avoid the added latency + // of blocking it. + + let GlyphRasterJobs { font, mut jobs } = { + profile_scope!("blocking wait on glyph_rx"); + self.glyph_rx + .recv() + .expect("BUG: Should be glyphs pending!") + }; + + // Ensure that the glyphs are always processed in the same + // order for a given text run (since iterating a hash set doesn't + // guarantee order). This can show up as very small float inaccuracy + // differences in rasterizers due to the different coordinates + // that text runs get associated with by the texture cache allocator. + jobs.sort_by(|a, b| a.key.cmp(&b.key)); + + let glyph_key_cache = glyph_cache.get_glyph_key_cache_for_font_mut(font); + + for GlyphRasterJob { key, result } in jobs { + let glyph_info = match result { + Err(_) => GlyphCacheEntry::Blank, + Ok(ref glyph) if glyph.width == 0 || glyph.height == 0 => { + GlyphCacheEntry::Blank + } + Ok(glyph) => { + let mut texture_cache_handle = TextureCacheHandle::invalid(); + texture_cache.request(&texture_cache_handle, gpu_cache); + texture_cache.update( + &mut texture_cache_handle, + ImageDescriptor { + size: size2(glyph.width, glyph.height), + stride: None, + format: glyph.format.image_format(), + flags: ImageDescriptorFlags::empty(), + offset: 0, + }, + TextureFilter::Linear, + Some(CachedImageData::Raw(Arc::new(glyph.bytes))), + [glyph.left, -glyph.top, glyph.scale], + DirtyRect::All, + gpu_cache, + Some(glyph_key_cache.eviction_notice()), + UvRectKind::Rect, + Eviction::Auto, + TargetShader::Text, + ); + GlyphCacheEntry::Cached(CachedGlyphInfo { + texture_cache_handle, + format: glyph.format, + }) + } + }; + glyph_key_cache.insert(key, glyph_info); + } + } + + // Now that we are done with the critical path (rendering the glyphs), + // we can schedule removing the fonts if needed. + self.remove_dead_fonts(); + + profile.end_time(profiler::GLYPH_RESOLVE_TIME); + } +} + +#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +pub struct FontTransform { + pub scale_x: f32, + pub skew_x: f32, + pub skew_y: f32, + pub scale_y: f32, +} + +// Floats don't impl Hash/Eq/Ord... +impl Eq for FontTransform {} +impl Ord for FontTransform { + fn cmp(&self, other: &Self) -> cmp::Ordering { + self.partial_cmp(other).unwrap_or(cmp::Ordering::Equal) + } +} +impl Hash for FontTransform { + fn hash<H: Hasher>(&self, state: &mut H) { + // Note: this is inconsistent with the Eq impl for -0.0 (don't care). + self.scale_x.to_bits().hash(state); + self.skew_x.to_bits().hash(state); + self.skew_y.to_bits().hash(state); + self.scale_y.to_bits().hash(state); + } +} + +impl FontTransform { + const QUANTIZE_SCALE: f32 = 1024.0; + + pub fn new(scale_x: f32, skew_x: f32, skew_y: f32, scale_y: f32) -> Self { + FontTransform { scale_x, skew_x, skew_y, scale_y } + } + + pub fn identity() -> Self { + FontTransform::new(1.0, 0.0, 0.0, 1.0) + } + + #[allow(dead_code)] + pub fn is_identity(&self) -> bool { + *self == FontTransform::identity() + } + + pub fn quantize(&self) -> Self { + FontTransform::new( + (self.scale_x * Self::QUANTIZE_SCALE).round() / Self::QUANTIZE_SCALE, + (self.skew_x * Self::QUANTIZE_SCALE).round() / Self::QUANTIZE_SCALE, + (self.skew_y * Self::QUANTIZE_SCALE).round() / Self::QUANTIZE_SCALE, + (self.scale_y * Self::QUANTIZE_SCALE).round() / Self::QUANTIZE_SCALE, + ) + } + + #[allow(dead_code)] + pub fn determinant(&self) -> f64 { + self.scale_x as f64 * self.scale_y as f64 - self.skew_y as f64 * self.skew_x as f64 + } + + #[allow(dead_code)] + pub fn compute_scale(&self) -> Option<(f64, f64)> { + let det = self.determinant(); + if det != 0.0 { + let x_scale = (self.scale_x as f64).hypot(self.skew_y as f64); + let y_scale = det.abs() / x_scale; + Some((x_scale, y_scale)) + } else { + None + } + } + + #[allow(dead_code)] + pub fn pre_scale(&self, scale_x: f32, scale_y: f32) -> Self { + FontTransform::new( + self.scale_x * scale_x, + self.skew_x * scale_y, + self.skew_y * scale_x, + self.scale_y * scale_y, + ) + } + + #[allow(dead_code)] + pub fn scale(&self, scale: f32) -> Self { self.pre_scale(scale, scale) } + + #[allow(dead_code)] + pub fn invert_scale(&self, x_scale: f64, y_scale: f64) -> Self { + self.pre_scale(x_scale.recip() as f32, y_scale.recip() as f32) + } + + pub fn synthesize_italics(&self, angle: SyntheticItalics, size: f64, vertical: bool) -> (Self, (f64, f64)) { + let skew_factor = angle.to_skew(); + if vertical { + // origin delta to be applied so that we effectively skew around + // the middle rather than edge of the glyph + let (tx, ty) = (0.0, -size * 0.5 * skew_factor as f64); + (FontTransform::new( + self.scale_x + self.skew_x * skew_factor, + self.skew_x, + self.skew_y + self.scale_y * skew_factor, + self.scale_y, + ), (self.scale_x as f64 * tx + self.skew_x as f64 * ty, + self.skew_y as f64 * tx + self.scale_y as f64 * ty)) + } else { + (FontTransform::new( + self.scale_x, + self.skew_x - self.scale_x * skew_factor, + self.skew_y, + self.scale_y - self.skew_y * skew_factor, + ), (0.0, 0.0)) + } + } + + pub fn swap_xy(&self) -> Self { + FontTransform::new(self.skew_x, self.scale_x, self.scale_y, self.skew_y) + } + + pub fn flip_x(&self) -> Self { + FontTransform::new(-self.scale_x, self.skew_x, -self.skew_y, self.scale_y) + } + + pub fn flip_y(&self) -> Self { + FontTransform::new(self.scale_x, -self.skew_x, self.skew_y, -self.scale_y) + } + + pub fn transform(&self, point: &LayoutPoint) -> DevicePoint { + DevicePoint::new( + self.scale_x * point.x + self.skew_x * point.y, + self.skew_y * point.x + self.scale_y * point.y, + ) + } + + pub fn get_subpx_dir(&self) -> SubpixelDirection { + if self.skew_y.approx_eq(&0.0) { + // The X axis is not projected onto the Y axis + SubpixelDirection::Horizontal + } else if self.scale_x.approx_eq(&0.0) { + // The X axis has been swapped with the Y axis + SubpixelDirection::Vertical + } else { + // Use subpixel precision on all axes + SubpixelDirection::Mixed + } + } +} + +impl<'a> From<&'a LayoutToWorldTransform> for FontTransform { + fn from(xform: &'a LayoutToWorldTransform) -> Self { + FontTransform::new(xform.m11, xform.m21, xform.m12, xform.m22) + } +} + +// Some platforms (i.e. Windows) may have trouble rasterizing glyphs above this size. +// Ensure glyph sizes are reasonably limited to avoid that scenario. +pub const FONT_SIZE_LIMIT: f32 = 320.0; + +/// A mutable font instance description. +/// +/// Performance is sensitive to the size of this structure, so it should only contain +/// the fields that we need to modify from the original base font instance. +#[derive(Clone, PartialEq, Eq, Debug, Ord, PartialOrd)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +pub struct FontInstance { + pub base: Arc<BaseFontInstance>, + pub transform: FontTransform, + pub render_mode: FontRenderMode, + pub flags: FontInstanceFlags, + pub color: ColorU, + // The font size is in *device/raster* pixels, not logical pixels. + // It is stored as an f32 since we need sub-pixel sizes. + pub size: FontSize, +} + +impl Hash for FontInstance { + fn hash<H: Hasher>(&self, state: &mut H) { + // Hash only the base instance's key to avoid the cost of hashing + // the rest. + self.base.instance_key.hash(state); + self.transform.hash(state); + self.render_mode.hash(state); + self.flags.hash(state); + self.color.hash(state); + self.size.hash(state); + } +} + +impl Deref for FontInstance { + type Target = BaseFontInstance; + fn deref(&self) -> &BaseFontInstance { + self.base.as_ref() + } +} + +impl MallocSizeOf for FontInstance { + fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize { 0 } +} + +impl FontInstance { + pub fn new( + base: Arc<BaseFontInstance>, + color: ColorU, + render_mode: FontRenderMode, + flags: FontInstanceFlags, + ) -> Self { + FontInstance { + transform: FontTransform::identity(), + color, + size: base.size, + base, + render_mode, + flags, + } + } + + pub fn from_base( + base: Arc<BaseFontInstance>, + ) -> Self { + FontInstance { + transform: FontTransform::identity(), + color: ColorU::new(0, 0, 0, 255), + size: base.size, + render_mode: base.render_mode, + flags: base.flags, + base, + } + } + + pub fn use_texture_padding(&self) -> bool { + self.flags.contains(FontInstanceFlags::TEXTURE_PADDING) + } + + pub fn use_transform_glyphs(&self) -> bool { + self.flags.contains(FontInstanceFlags::TRANSFORM_GLYPHS) + } + + pub fn get_alpha_glyph_format(&self) -> GlyphFormat { + if self.use_transform_glyphs() { GlyphFormat::TransformedAlpha } else { GlyphFormat::Alpha } + } + + pub fn get_subpixel_glyph_format(&self) -> GlyphFormat { + if self.use_transform_glyphs() { GlyphFormat::TransformedSubpixel } else { GlyphFormat::Subpixel } + } + + pub fn disable_subpixel_aa(&mut self) { + self.render_mode = self.render_mode.limit_by(FontRenderMode::Alpha); + } + + pub fn disable_subpixel_position(&mut self) { + self.flags.remove(FontInstanceFlags::SUBPIXEL_POSITION); + } + + pub fn use_subpixel_position(&self) -> bool { + self.flags.contains(FontInstanceFlags::SUBPIXEL_POSITION) && + self.render_mode != FontRenderMode::Mono + } + + pub fn get_subpx_dir(&self) -> SubpixelDirection { + if self.use_subpixel_position() { + let mut subpx_dir = self.transform.get_subpx_dir(); + if self.flags.contains(FontInstanceFlags::TRANSPOSE) { + subpx_dir = subpx_dir.swap_xy(); + } + subpx_dir + } else { + SubpixelDirection::None + } + } + + #[allow(dead_code)] + pub fn get_subpx_offset(&self, glyph: &GlyphKey) -> (f64, f64) { + if self.use_subpixel_position() { + let (dx, dy) = glyph.subpixel_offset(); + (dx.into(), dy.into()) + } else { + (0.0, 0.0) + } + } + + #[allow(dead_code)] + pub fn get_glyph_format(&self) -> GlyphFormat { + match self.render_mode { + FontRenderMode::Mono | FontRenderMode::Alpha => self.get_alpha_glyph_format(), + FontRenderMode::Subpixel => self.get_subpixel_glyph_format(), + } + } + + #[allow(dead_code)] + pub fn get_extra_strikes(&self, x_scale: f64) -> usize { + if self.flags.contains(FontInstanceFlags::SYNTHETIC_BOLD) { + let mut bold_offset = self.size.to_f64_px() / 48.0; + if bold_offset < 1.0 { + bold_offset = 0.25 + 0.75 * bold_offset; + } + (bold_offset * x_scale).max(1.0).round() as usize + } else { + 0 + } + } + + pub fn synthesize_italics(&self, transform: FontTransform, size: f64) -> (FontTransform, (f64, f64)) { + transform.synthesize_italics(self.synthetic_italics, size, self.flags.contains(FontInstanceFlags::VERTICAL)) + } + + #[allow(dead_code)] + pub fn get_transformed_size(&self) -> f64 { + let (_, y_scale) = self.transform.compute_scale().unwrap_or((1.0, 1.0)); + self.size.to_f64_px() * y_scale + } +} + +#[repr(u32)] +#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug, Ord, PartialOrd)] +pub enum SubpixelDirection { + None = 0, + Horizontal, + Vertical, + Mixed, +} + +impl SubpixelDirection { + // Limit the subpixel direction to what is supported by the glyph format. + pub fn limit_by(self, glyph_format: GlyphFormat) -> Self { + match glyph_format { + GlyphFormat::Bitmap | + GlyphFormat::ColorBitmap => SubpixelDirection::None, + _ => self, + } + } + + pub fn swap_xy(self) -> Self { + match self { + SubpixelDirection::None | SubpixelDirection::Mixed => self, + SubpixelDirection::Horizontal => SubpixelDirection::Vertical, + SubpixelDirection::Vertical => SubpixelDirection::Horizontal, + } + } +} + +#[repr(u8)] +#[derive(Hash, Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +pub enum SubpixelOffset { + Zero = 0, + Quarter = 1, + Half = 2, + ThreeQuarters = 3, +} + +impl SubpixelOffset { + // Skia quantizes subpixel offsets into 1/4 increments. + // Given the absolute position, return the quantized increment + fn quantize(pos: f32) -> Self { + // Following the conventions of Gecko and Skia, we want + // to quantize the subpixel position, such that abs(pos) gives: + // [0.0, 0.125) -> Zero + // [0.125, 0.375) -> Quarter + // [0.375, 0.625) -> Half + // [0.625, 0.875) -> ThreeQuarters, + // [0.875, 1.0) -> Zero + // The unit tests below check for this. + let apos = ((pos - pos.floor()) * 8.0) as i32; + + match apos { + 1..=2 => SubpixelOffset::Quarter, + 3..=4 => SubpixelOffset::Half, + 5..=6 => SubpixelOffset::ThreeQuarters, + _ => SubpixelOffset::Zero, + } + } +} + +impl Into<f64> for SubpixelOffset { + fn into(self) -> f64 { + match self { + SubpixelOffset::Zero => 0.0, + SubpixelOffset::Quarter => 0.25, + SubpixelOffset::Half => 0.5, + SubpixelOffset::ThreeQuarters => 0.75, + } + } +} + +#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug, Ord, PartialOrd)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +pub struct GlyphKey(u32); + +impl GlyphKey { + pub fn new( + index: u32, + point: DevicePoint, + subpx_dir: SubpixelDirection, + ) -> Self { + let (dx, dy) = match subpx_dir { + SubpixelDirection::None => (0.0, 0.0), + SubpixelDirection::Horizontal => (point.x, 0.0), + SubpixelDirection::Vertical => (0.0, point.y), + SubpixelDirection::Mixed => (point.x, point.y), + }; + let sox = SubpixelOffset::quantize(dx); + let soy = SubpixelOffset::quantize(dy); + assert_eq!(0, index & 0xF0000000); + + GlyphKey(index | (sox as u32) << 28 | (soy as u32) << 30) + } + + pub fn index(&self) -> GlyphIndex { + self.0 & 0x0FFFFFFF + } + + fn subpixel_offset(&self) -> (SubpixelOffset, SubpixelOffset) { + let x = (self.0 >> 28) as u8 & 3; + let y = (self.0 >> 30) as u8 & 3; + unsafe { + (mem::transmute(x), mem::transmute(y)) + } + } +} + +#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +#[allow(dead_code)] +pub enum GlyphFormat { + Alpha, + TransformedAlpha, + Subpixel, + TransformedSubpixel, + Bitmap, + ColorBitmap, +} + +impl GlyphFormat { + pub fn ignore_color(self) -> Self { + match self { + GlyphFormat::ColorBitmap => GlyphFormat::Bitmap, + _ => self, + } + } + + /// Returns the ImageFormat that a glyph should be stored as in the texture cache. + pub fn image_format(&self) -> ImageFormat { + // GlyphFormat::Alpha and GlyphFormat::TransformedAlpha should be stored in an R8 + // texture, but we ran in to some rendering issues on various platforms after doing so. + // So keep using BGRA8 for all glyph formats until those are solved. + // See bug 1687554. + ImageFormat::BGRA8 + } +} + +pub struct RasterizedGlyph { + pub top: f32, + pub left: f32, + pub width: i32, + pub height: i32, + pub scale: f32, + pub format: GlyphFormat, + pub bytes: Vec<u8>, +} + +impl RasterizedGlyph { + #[allow(dead_code)] + pub fn downscale_bitmap_if_required(&mut self, font: &FontInstance) { + // Check if the glyph is going to be downscaled in the shader. If the scaling is + // less than 0.5, that means bilinear filtering can't effectively filter the glyph + // without aliasing artifacts. + // + // Instead of fixing this by mipmapping the glyph cache texture, rather manually + // produce the appropriate mip level for individual glyphs where bilinear filtering + // will still produce acceptable results. + match self.format { + GlyphFormat::Bitmap | GlyphFormat::ColorBitmap => {}, + _ => return, + } + let (x_scale, y_scale) = font.transform.compute_scale().unwrap_or((1.0, 1.0)); + let upscaled = x_scale.max(y_scale) as f32; + let mut new_scale = self.scale; + if new_scale * upscaled <= 0.0 { + return; + } + let mut steps = 0; + while new_scale * upscaled <= 0.5 { + new_scale *= 2.0; + steps += 1; + } + // If no mipping is necessary, just bail. + if steps == 0 { + return; + } + + // Calculate the actual size of the mip level. + let new_width = (self.width as usize + (1 << steps) - 1) >> steps; + let new_height = (self.height as usize + (1 << steps) - 1) >> steps; + let mut new_bytes: Vec<u8> = Vec::with_capacity(new_width * new_height * 4); + + // Produce destination pixels by applying a box filter to the source pixels. + // The box filter corresponds to how graphics drivers may generate mipmaps. + for y in 0 .. new_height { + for x in 0 .. new_width { + // Calculate the number of source samples that contribute to the destination pixel. + let src_y = y << steps; + let src_x = x << steps; + let y_samples = (1 << steps).min(self.height as usize - src_y); + let x_samples = (1 << steps).min(self.width as usize - src_x); + let num_samples = (x_samples * y_samples) as u32; + + let mut src_idx = (src_y * self.width as usize + src_x) * 4; + // Initialize the accumulator with half an increment so that when later divided + // by the sample count, it will effectively round the accumulator to the nearest + // increment. + let mut accum = [num_samples / 2; 4]; + // Accumulate all the contributing source sampless. + for _ in 0 .. y_samples { + for _ in 0 .. x_samples { + accum[0] += self.bytes[src_idx + 0] as u32; + accum[1] += self.bytes[src_idx + 1] as u32; + accum[2] += self.bytes[src_idx + 2] as u32; + accum[3] += self.bytes[src_idx + 3] as u32; + src_idx += 4; + } + src_idx += (self.width as usize - x_samples) * 4; + } + + // Finally, divide by the sample count to get the mean value for the new pixel. + new_bytes.extend_from_slice(&[ + (accum[0] / num_samples) as u8, + (accum[1] / num_samples) as u8, + (accum[2] / num_samples) as u8, + (accum[3] / num_samples) as u8, + ]); + } + } + + // Fix the bounds for the new glyph data. + self.top /= (1 << steps) as f32; + self.left /= (1 << steps) as f32; + self.width = new_width as i32; + self.height = new_height as i32; + self.scale = new_scale; + self.bytes = new_bytes; + } +} + +pub struct FontContexts { + // These worker are mostly accessed from their corresponding worker threads. + // The goal is that there should be no noticeable contention on the mutexes. + worker_contexts: Vec<Mutex<FontContext>>, + // This worker should be accessed by threads that don't belong to the thread pool + // (in theory that's only the render backend thread so no contention expected either). + shared_context: Mutex<FontContext>, + // Stored here as a convenience to get the current thread index. + #[allow(dead_code)] + workers: Arc<ThreadPool>, + locked_mutex: Mutex<bool>, + locked_cond: Condvar, +} + +impl FontContexts { + + /// Get access to any particular font context. + /// + /// The id is ```Some(i)``` where i is an index between 0 and num_worker_contexts + /// for font contexts associated to the thread pool, and None for the shared + /// global font context for use outside of the thread pool. + pub fn lock_context(&self, id: Option<usize>) -> MutexGuard<FontContext> { + match id { + Some(index) => self.worker_contexts[index].lock().unwrap(), + None => self.shared_context.lock().unwrap(), + } + } + + /// Get access to the font context usable outside of the thread pool. + pub fn lock_shared_context(&self) -> MutexGuard<FontContext> { + self.shared_context.lock().unwrap() + } + + // number of contexts associated to workers + pub fn num_worker_contexts(&self) -> usize { + self.worker_contexts.len() + } +} + +pub trait AsyncForEach<T> { + fn async_for_each<F: Fn(MutexGuard<T>) + Send + 'static>(&self, f: F); +} + +impl AsyncForEach<FontContext> for Arc<FontContexts> { + fn async_for_each<F: Fn(MutexGuard<FontContext>) + Send + 'static>(&self, f: F) { + // Reset the locked condition. + let mut locked = self.locked_mutex.lock().unwrap(); + *locked = false; + + // Arc that can be safely moved into a spawn closure. + let font_contexts = self.clone(); + // Spawn a new thread on which to run the for-each off the main thread. + self.workers.spawn(move || { + // Lock the shared and worker contexts up front. + let mut locks = Vec::with_capacity(font_contexts.num_worker_contexts() + 1); + locks.push(font_contexts.lock_shared_context()); + for i in 0 .. font_contexts.num_worker_contexts() { + locks.push(font_contexts.lock_context(Some(i))); + } + + // Signal the locked condition now that all contexts are locked. + *font_contexts.locked_mutex.lock().unwrap() = true; + font_contexts.locked_cond.notify_all(); + + // Now that everything is locked, proceed to processing each locked context. + for context in locks { + f(context); + } + }); + + // Wait for locked condition before resuming. Safe to proceed thereafter + // since any other thread that needs to use a FontContext will try to lock + // it first. + while !*locked { + locked = self.locked_cond.wait(locked).unwrap(); + } + } +} + +pub struct GlyphRasterizer { + #[allow(dead_code)] + workers: Arc<ThreadPool>, + font_contexts: Arc<FontContexts>, + + /// The current number of individual glyphs waiting in pending batches. + pending_glyph_count: usize, + + /// The current number of glyph request jobs that have been kicked to worker threads. + pending_glyph_jobs: usize, + + /// The number of glyphs requested this frame. + glyph_request_count: usize, + + /// A map of current glyph request batches. + pending_glyph_requests: FastHashMap<FontInstance, SmallVec<[GlyphKey; 16]>>, + + // Receives the rendered glyphs. + glyph_rx: Receiver<GlyphRasterJobs>, + glyph_tx: Sender<GlyphRasterJobs>, + + // We defer removing fonts to the end of the frame so that: + // - this work is done outside of the critical path, + // - we don't have to worry about the ordering of events if a font is used on + // a frame where it is used (although it seems unlikely). + fonts_to_remove: Vec<FontKey>, + // Defer removal of font instances, as for fonts. + font_instances_to_remove: Vec<FontInstance>, + + // Whether to parallelize glyph rasterization with rayon. + enable_multithreading: bool, +} + +impl GlyphRasterizer { + pub fn new(workers: Arc<ThreadPool>) -> Result<Self, ResourceCacheError> { + let (glyph_tx, glyph_rx) = unbounded_channel(); + + let num_workers = workers.current_num_threads(); + let mut contexts = Vec::with_capacity(num_workers); + + let shared_context = FontContext::new()?; + + for _ in 0 .. num_workers { + contexts.push(Mutex::new(FontContext::new()?)); + } + + let font_context = FontContexts { + worker_contexts: contexts, + shared_context: Mutex::new(shared_context), + workers: Arc::clone(&workers), + locked_mutex: Mutex::new(false), + locked_cond: Condvar::new(), + }; + + Ok(GlyphRasterizer { + font_contexts: Arc::new(font_context), + pending_glyph_jobs: 0, + pending_glyph_count: 0, + glyph_request_count: 0, + glyph_rx, + glyph_tx, + workers, + fonts_to_remove: Vec::new(), + font_instances_to_remove: Vec::new(), + enable_multithreading: true, + pending_glyph_requests: FastHashMap::default(), + }) + } + + pub fn add_font(&mut self, font_key: FontKey, template: FontTemplate) { + self.font_contexts.async_for_each(move |mut context| { + context.add_font(&font_key, &template); + }); + } + + pub fn delete_font(&mut self, font_key: FontKey) { + self.fonts_to_remove.push(font_key); + } + + pub fn delete_font_instance(&mut self, instance: &FontInstance) { + self.font_instances_to_remove.push(instance.clone()); + } + + pub fn prepare_font(&self, font: &mut FontInstance) { + FontContext::prepare_font(font); + + // Quantize the transform to minimize thrashing of the glyph cache, but + // only quantize the transform when preparing to access the glyph cache. + // This way, the glyph subpixel positions, which are calculated before + // this, can still use the precise transform which is required to match + // the subpixel positions computed for glyphs in the text run shader. + font.transform = font.transform.quantize(); + } + + pub fn get_glyph_dimensions( + &mut self, + font: &FontInstance, + glyph_index: GlyphIndex, + ) -> Option<GlyphDimensions> { + let glyph_key = GlyphKey::new( + glyph_index, + DevicePoint::zero(), + SubpixelDirection::None, + ); + + self.font_contexts + .lock_shared_context() + .get_glyph_dimensions(font, &glyph_key) + } + + pub fn get_glyph_index(&mut self, font_key: FontKey, ch: char) -> Option<u32> { + self.font_contexts + .lock_shared_context() + .get_glyph_index(font_key, ch) + } + + fn remove_dead_fonts(&mut self) { + if self.fonts_to_remove.is_empty() && self.font_instances_to_remove.is_empty() { + return + } + + profile_scope!("remove_dead_fonts"); + let fonts_to_remove = mem::replace(&mut self.fonts_to_remove, Vec::new()); + let font_instances_to_remove = mem::replace(& mut self.font_instances_to_remove, Vec::new()); + self.font_contexts.async_for_each(move |mut context| { + for font_key in &fonts_to_remove { + context.delete_font(font_key); + } + for instance in &font_instances_to_remove { + context.delete_font_instance(instance); + } + }); + } + + #[cfg(feature = "replay")] + pub fn reset(&mut self) { + //TODO: any signals need to be sent to the workers? + self.pending_glyph_jobs = 0; + self.pending_glyph_count = 0; + self.glyph_request_count = 0; + self.fonts_to_remove.clear(); + self.font_instances_to_remove.clear(); + } +} + +trait AddFont { + fn add_font(&mut self, font_key: &FontKey, template: &FontTemplate); +} + +impl AddFont for FontContext { + fn add_font(&mut self, font_key: &FontKey, template: &FontTemplate) { + match *template { + FontTemplate::Raw(ref bytes, index) => { + self.add_raw_font(font_key, bytes.clone(), index); + } + FontTemplate::Native(ref native_font_handle) => { + self.add_native_font(font_key, (*native_font_handle).clone()); + } + } + } +} + +#[allow(dead_code)] +pub(in crate::glyph_rasterizer) struct GlyphRasterJob { + key: GlyphKey, + result: GlyphRasterResult, +} + +#[allow(dead_code)] +pub enum GlyphRasterError { + LoadFailed, +} + +#[allow(dead_code)] +pub type GlyphRasterResult = Result<RasterizedGlyph, GlyphRasterError>; + +#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq)] +#[cfg_attr(feature = "capture", derive(Serialize))] +#[cfg_attr(feature = "replay", derive(Deserialize))] +pub struct GpuGlyphCacheKey(pub u32); + +#[allow(dead_code)] +struct GlyphRasterJobs { + font: FontInstance, + jobs: Vec<GlyphRasterJob>, +} + +#[cfg(test)] +mod test_glyph_rasterizer { + pub const FORMAT: api::ImageFormat = api::ImageFormat::BGRA8; + + #[test] + fn rasterize_200_glyphs() { + // This test loads a font from disc, the renders 4 requests containing + // 50 glyphs each, deletes the font and waits for the result. + + use rayon::ThreadPoolBuilder; + use std::fs::File; + use std::io::Read; + use crate::texture_cache::TextureCache; + use crate::glyph_cache::GlyphCache; + use crate::gpu_cache::GpuCache; + use crate::profiler::TransactionProfile; + use api::{FontKey, FontInstanceKey, FontSize, FontTemplate, FontRenderMode, + IdNamespace, ColorU}; + use api::units::DevicePoint; + use std::sync::Arc; + use crate::glyph_rasterizer::{FontInstance, BaseFontInstance, GlyphKey, GlyphRasterizer}; + + let worker = ThreadPoolBuilder::new() + .thread_name(|idx|{ format!("WRWorker#{}", idx) }) + .build(); + let workers = Arc::new(worker.unwrap()); + let mut glyph_rasterizer = GlyphRasterizer::new(workers).unwrap(); + let mut glyph_cache = GlyphCache::new(); + let mut gpu_cache = GpuCache::new_for_testing(); + let mut texture_cache = TextureCache::new_for_testing(2048, FORMAT); + let mut font_file = + File::open("../wrench/reftests/text/VeraBd.ttf").expect("Couldn't open font file"); + let mut font_data = vec![]; + font_file + .read_to_end(&mut font_data) + .expect("failed to read font file"); + + let font_key = FontKey::new(IdNamespace(0), 0); + glyph_rasterizer.add_font(font_key, FontTemplate::Raw(Arc::new(font_data), 0)); + + let font = FontInstance::from_base(Arc::new(BaseFontInstance { + instance_key: FontInstanceKey(IdNamespace(0), 0), + font_key, + size: FontSize::from_f32_px(32.0), + bg_color: ColorU::new(0, 0, 0, 0), + render_mode: FontRenderMode::Subpixel, + flags: Default::default(), + synthetic_italics: Default::default(), + platform_options: None, + variations: Vec::new(), + })); + + let subpx_dir = font.get_subpx_dir(); + + let mut glyph_keys = Vec::with_capacity(200); + for i in 0 .. 200 { + glyph_keys.push(GlyphKey::new( + i, + DevicePoint::zero(), + subpx_dir, + )); + } + + for i in 0 .. 4 { + glyph_rasterizer.request_glyphs( + &mut glyph_cache, + font.clone(), + &glyph_keys[(50 * i) .. (50 * (i + 1))], + &mut texture_cache, + &mut gpu_cache, + ); + } + + glyph_rasterizer.delete_font(font_key); + + glyph_rasterizer.resolve_glyphs( + &mut glyph_cache, + &mut TextureCache::new_for_testing(4096, FORMAT), + &mut gpu_cache, + &mut TransactionProfile::new(), + ); + } + + #[test] + fn rasterize_large_glyphs() { + // This test loads a font from disc and rasterize a few glyphs with a size of 200px to check + // that the texture cache handles them properly. + use rayon::ThreadPoolBuilder; + use std::fs::File; + use std::io::Read; + use crate::texture_cache::TextureCache; + use crate::glyph_cache::GlyphCache; + use crate::gpu_cache::GpuCache; + use crate::profiler::TransactionProfile; + use api::{FontKey, FontInstanceKey, FontSize, FontTemplate, FontRenderMode, + IdNamespace, ColorU}; + use api::units::DevicePoint; + use std::sync::Arc; + use crate::glyph_rasterizer::{FontInstance, BaseFontInstance, GlyphKey, GlyphRasterizer}; + + let worker = ThreadPoolBuilder::new() + .thread_name(|idx|{ format!("WRWorker#{}", idx) }) + .build(); + let workers = Arc::new(worker.unwrap()); + let mut glyph_rasterizer = GlyphRasterizer::new(workers).unwrap(); + let mut glyph_cache = GlyphCache::new(); + let mut gpu_cache = GpuCache::new_for_testing(); + let mut texture_cache = TextureCache::new_for_testing(2048, FORMAT); + let mut font_file = + File::open("../wrench/reftests/text/VeraBd.ttf").expect("Couldn't open font file"); + let mut font_data = vec![]; + font_file + .read_to_end(&mut font_data) + .expect("failed to read font file"); + + let font_key = FontKey::new(IdNamespace(0), 0); + glyph_rasterizer.add_font(font_key, FontTemplate::Raw(Arc::new(font_data), 0)); + + let font = FontInstance::from_base(Arc::new(BaseFontInstance { + instance_key: FontInstanceKey(IdNamespace(0), 0), + font_key, + size: FontSize::from_f32_px(200.0), + bg_color: ColorU::new(0, 0, 0, 0), + render_mode: FontRenderMode::Subpixel, + flags: Default::default(), + synthetic_italics: Default::default(), + platform_options: None, + variations: Vec::new(), + })); + + let subpx_dir = font.get_subpx_dir(); + + let mut glyph_keys = Vec::with_capacity(10); + for i in 0 .. 10 { + glyph_keys.push(GlyphKey::new( + i, + DevicePoint::zero(), + subpx_dir, + )); + } + + glyph_rasterizer.request_glyphs( + &mut glyph_cache, + font.clone(), + &glyph_keys, + &mut texture_cache, + &mut gpu_cache, + ); + + glyph_rasterizer.delete_font(font_key); + + glyph_rasterizer.resolve_glyphs( + &mut glyph_cache, + &mut TextureCache::new_for_testing(4096, FORMAT), + &mut gpu_cache, + &mut TransactionProfile::new(), + ); + } + + #[test] + fn test_subpx_quantize() { + use crate::glyph_rasterizer::SubpixelOffset; + + assert_eq!(SubpixelOffset::quantize(0.0), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(-0.0), SubpixelOffset::Zero); + + assert_eq!(SubpixelOffset::quantize(0.1), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.01), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.05), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.12), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.124), SubpixelOffset::Zero); + + assert_eq!(SubpixelOffset::quantize(0.125), SubpixelOffset::Quarter); + assert_eq!(SubpixelOffset::quantize(0.2), SubpixelOffset::Quarter); + assert_eq!(SubpixelOffset::quantize(0.25), SubpixelOffset::Quarter); + assert_eq!(SubpixelOffset::quantize(0.33), SubpixelOffset::Quarter); + assert_eq!(SubpixelOffset::quantize(0.374), SubpixelOffset::Quarter); + + assert_eq!(SubpixelOffset::quantize(0.375), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(0.4), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(0.5), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(0.58), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(0.624), SubpixelOffset::Half); + + assert_eq!(SubpixelOffset::quantize(0.625), SubpixelOffset::ThreeQuarters); + assert_eq!(SubpixelOffset::quantize(0.67), SubpixelOffset::ThreeQuarters); + assert_eq!(SubpixelOffset::quantize(0.7), SubpixelOffset::ThreeQuarters); + assert_eq!(SubpixelOffset::quantize(0.78), SubpixelOffset::ThreeQuarters); + assert_eq!(SubpixelOffset::quantize(0.874), SubpixelOffset::ThreeQuarters); + + assert_eq!(SubpixelOffset::quantize(0.875), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.89), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.91), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.967), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(0.999), SubpixelOffset::Zero); + + assert_eq!(SubpixelOffset::quantize(-1.0), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(1.0), SubpixelOffset::Zero); + assert_eq!(SubpixelOffset::quantize(1.5), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(-1.625), SubpixelOffset::Half); + assert_eq!(SubpixelOffset::quantize(-4.33), SubpixelOffset::ThreeQuarters); + } +} |