Add //impeller/typographer. (flutter#36)

Renders shaped text frames. Has the ability to plug into to different text shapers and render glyphs using different techniques. For now, the Aiks layer expects a prepared glyph atlas. But this will be changed so that render pass will be responsible for preparing these and setting these on the content renderer after pass consolidation.
egramond · Apr 27, 2022 · 0dae5ad · 0dae5ad
1 parent 451f93e
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Showing 63 changed files with 1,778 additions and 23 deletions.
diff --git a/impeller/BUILD.gn b/impeller/BUILD.gn
@@ -21,6 +21,7 @@ group("impeller") {
     "geometry",
     "image",
     "renderer",
+    "typographer",
   ]
 
   if (is_host) {
@@ -43,5 +44,6 @@ executable("impeller_unittests") {
     "image:image_unittests",
     "playground",
     "renderer:renderer_unittests",
+    "typographer:typographer_unittests",
   ]
 }
diff --git a/impeller/aiks/aiks_unittests.cc b/impeller/aiks/aiks_unittests.cc
@@ -8,6 +8,9 @@
 #include "impeller/aiks/image.h"
 #include "impeller/geometry/geometry_unittests.h"
 #include "impeller/geometry/path_builder.h"
+#include "impeller/typographer/backends/skia/text_frame_skia.h"
+#include "impeller/typographer/backends/skia/text_render_context_skia.h"
+#include "third_party/skia/include/core/SkData.h"
 
 namespace impeller {
 namespace testing {
@@ -283,5 +286,114 @@ TEST_F(AiksTest, CanRenderDifferencePaths) {
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 
+static sk_sp<SkData> OpenFixtureAsSkData(const char* fixture_name) {
+  auto mapping = flutter::testing::OpenFixtureAsMapping(fixture_name);
+  if (!mapping) {
+    return nullptr;
+  }
+  return SkData::MakeWithProc(
+      mapping->GetMapping(), mapping->GetSize(),
+      [](const void* ptr, void* context) {
+        delete reinterpret_cast<fml::Mapping*>(context);
+      },
+      mapping.release());
+}
+
+TEST_F(AiksTest, CanRenderTextFrame) {
+  Canvas canvas;
+
+  Scalar baseline = 200.0;
+  Point text_position = {100, baseline};
+
+  // Draw the baseline.
+  canvas.DrawRect({50, baseline, 900, 10},
+                  Paint{.color = Color::Aqua().WithAlpha(0.25)});
+
+  // Mark the point at which the text is drawn.
+  canvas.DrawCircle(text_position, 5.0,
+                    Paint{.color = Color::Red().WithAlpha(0.25)});
+
+  // Construct the text blob.
+  auto mapping = OpenFixtureAsSkData("Roboto-Regular.ttf");
+  ASSERT_TRUE(mapping);
+  SkFont sk_font(SkTypeface::MakeFromData(mapping), 50.0);
+  auto blob = SkTextBlob::MakeFromString(
+      "the quick brown fox jumped over the lazy dog!.?", sk_font);
+  ASSERT_TRUE(blob);
+
+  // Create the Impeller text frame and draw it at the designated baseline.
+  auto frame = TextFrameFromTextBlob(blob);
+  TextRenderContextSkia text_context(GetContext());
+  ASSERT_TRUE(text_context.IsValid());
+  auto atlas = text_context.CreateGlyphAtlas(frame);
+  ASSERT_NE(atlas, nullptr);
+  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position);
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
+TEST_F(AiksTest, CanRenderItalicizedText) {
+  Canvas canvas;
+
+  Scalar baseline = 200.0;
+  Point text_position = {100, baseline};
+
+  // Draw the baseline.
+  canvas.DrawRect({50, baseline, 900, 10},
+                  Paint{.color = Color::Aqua().WithAlpha(0.25)});
+
+  // Mark the point at which the text is drawn.
+  canvas.DrawCircle(text_position, 5.0,
+                    Paint{.color = Color::Red().WithAlpha(0.25)});
+
+  // Construct the text blob.
+  auto mapping = OpenFixtureAsSkData("HomemadeApple.ttf");
+  ASSERT_TRUE(mapping);
+  SkFont sk_font(SkTypeface::MakeFromData(mapping), 50.0);
+  auto blob = SkTextBlob::MakeFromString(
+      "the quick brown fox jumped over the lazy dog!.?", sk_font);
+  ASSERT_TRUE(blob);
+
+  // Create the Impeller text frame and draw it at the designated baseline.
+  auto frame = TextFrameFromTextBlob(blob);
+  TextRenderContextSkia text_context(GetContext());
+  ASSERT_TRUE(text_context.IsValid());
+  auto atlas = text_context.CreateGlyphAtlas(frame);
+  ASSERT_NE(atlas, nullptr);
+  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position);
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
+TEST_F(AiksTest, CanRenderEmojiTextFrame) {
+  Canvas canvas;
+
+  Scalar baseline = 200.0;
+  Point text_position = {100, baseline};
+
+  // Draw the baseline.
+  canvas.DrawRect({50, baseline, 900, 10},
+                  Paint{.color = Color::Aqua().WithAlpha(0.25)});
+
+  // Mark the point at which the text is drawn.
+  canvas.DrawCircle(text_position, 5.0,
+                    Paint{.color = Color::Red().WithAlpha(0.25)});
+
+  // Construct the text blob.
+  auto mapping = OpenFixtureAsSkData("NotoColorEmoji.ttf");
+  ASSERT_TRUE(mapping);
+  SkFont sk_font(SkTypeface::MakeFromData(mapping), 50.0);
+  auto blob = SkTextBlob::MakeFromString(
+      "😀 😃 😄 😁 😆 😅 😂 🤣 🥲 ☺️ 😊", sk_font);
+  ASSERT_TRUE(blob);
+
+  // Create the Impeller text frame and draw it at the designated baseline.
+  auto frame = TextFrameFromTextBlob(blob);
+  TextRenderContextSkia text_context(GetContext());
+  ASSERT_TRUE(text_context.IsValid());
+  auto atlas = text_context.CreateGlyphAtlas(frame);
+  ASSERT_NE(atlas, nullptr);
+  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position);
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
 }  // namespace testing
 }  // namespace impeller
diff --git a/impeller/aiks/canvas.cc b/impeller/aiks/canvas.cc
@@ -252,4 +252,25 @@ void Canvas::Save(bool create_subpass) {
   xformation_stack_.emplace_back(std::move(entry));
 }
 
+void Canvas::DrawTextFrame(TextFrame text_frame,
+                           std::shared_ptr<GlyphAtlas> atlas,
+                           Point position) {
+  if (!atlas || !atlas->IsValid()) {
+    return;
+  }
+
+  auto text_contents = std::make_shared<TextContents>();
+  text_contents->SetTextFrame(std::move(text_frame));
+  text_contents->SetGlyphAtlas(std::move(atlas));
+
+  Entity entity;
+  entity.SetTransformation(GetCurrentTransformation() *
+                           Matrix::MakeTranslation(position));
+  entity.SetPath({});
+  entity.SetStencilDepth(GetStencilDepth());
+  entity.SetContents(std::move(text_contents));
+
+  GetCurrentPass().AddEntity(std::move(entity));
+}
+
 }  // namespace impeller
diff --git a/impeller/aiks/canvas.h b/impeller/aiks/canvas.h
@@ -18,6 +18,7 @@
 #include "impeller/geometry/path.h"
 #include "impeller/geometry/point.h"
 #include "impeller/geometry/vector.h"
+#include "impeller/typographer/text_frame.h"
 
 namespace impeller {
 
@@ -74,6 +75,10 @@ class Canvas {
 
   void DrawPicture(Picture picture);
 
+  void DrawTextFrame(TextFrame text_frame,
+                     std::shared_ptr<GlyphAtlas> atlas,
+                     Point position);
+
   Picture EndRecordingAsPicture();
 
  private:

diff --git a/impeller/aiks/paint.cc b/impeller/aiks/paint.cc
@@ -7,6 +7,10 @@
 namespace impeller {
 
 std::shared_ptr<Contents> Paint::CreateContentsForEntity() const {
+  if (contents) {
+    return contents;
+  }
+
   switch (style) {
     case Style::kFill: {
       auto solid_color = std::make_shared<SolidColorContents>();

diff --git a/impeller/aiks/paint.h b/impeller/aiks/paint.h
@@ -21,6 +21,7 @@ struct Paint {
   Color color = Color::Black();
   Scalar stroke_width = 0.0;
   Style style = Style::kFill;
+  std::shared_ptr<Contents> contents;
 
   std::shared_ptr<Contents> CreateContentsForEntity() const;
 };

diff --git a/impeller/base/BUILD.gn b/impeller/base/BUILD.gn
@@ -8,6 +8,7 @@ impeller_component("base") {
   sources = [
     "allocation.cc",
     "allocation.h",
+    "backend_cast.h",
     "base.h",
     "config.h",
     "promise.cc",

diff --git a/impeller/base/allocation.cc b/impeller/base/allocation.cc
@@ -38,7 +38,7 @@ bool Allocation::Truncate(size_t length, bool npot) {
   return true;
 }
 
-static uint32_t NextPowerOfTwoSize(uint32_t x) {
+uint32_t Allocation::NextPowerOfTwoSize(uint32_t x) {
   if (x == 0) {
     return 1;
   }

diff --git a/impeller/base/allocation.h b/impeller/base/allocation.h
@@ -25,6 +25,8 @@ class Allocation {
 
   [[nodiscard]] bool Truncate(size_t length, bool npot = true);
 
+  static uint32_t NextPowerOfTwoSize(uint32_t x);
+
  private:
   uint8_t* buffer_ = nullptr;
   size_t length_ = 0;

diff --git a/...ler/renderer/backend/metal/backend_cast.h → impeller/base/backend_cast.h b/...ler/renderer/backend/metal/backend_cast.h → impeller/base/backend_cast.h
diff --git a/impeller/display_list/display_list_dispatcher.cc b/impeller/display_list/display_list_dispatcher.cc
@@ -6,6 +6,9 @@
 
 #include "flutter/fml/trace_event.h"
 #include "impeller/geometry/path_builder.h"
+#include "impeller/typographer/backends/skia/text_frame_skia.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkShader.h"
 
 namespace impeller {
 
@@ -72,8 +75,56 @@ void DisplayListDispatcher::setStrokeJoin(SkPaint::Join join) {
   UNIMPLEMENTED;
 }
 
+static Point ToPoint(const SkPoint& point) {
+  return Point::MakeXY(point.fX, point.fY);
+}
+
+static Color ToColor(const SkColor& color) {
+  return {
+      static_cast<Scalar>(SkColorGetR(color) / 255.0),  //
+      static_cast<Scalar>(SkColorGetG(color) / 255.0),  //
+      static_cast<Scalar>(SkColorGetB(color) / 255.0),  //
+      static_cast<Scalar>(SkColorGetA(color) / 255.0)   //
+  };
+}
+
 // |flutter::Dispatcher|
 void DisplayListDispatcher::setShader(sk_sp<SkShader> shader) {
+  if (!shader) {
+    return;
+  }
+
+  {
+    SkShader::GradientInfo info = {};
+    constexpr auto kColorsArrayCount = 2u;
+    info.fColorCount = kColorsArrayCount;
+    SkColor sk_colors[kColorsArrayCount];
+    info.fColors = sk_colors;
+    auto gradient_type = shader->asAGradient(&info);
+    switch (gradient_type) {
+      case SkShader::kLinear_GradientType: {
+        auto contents = std::make_shared<LinearGradientContents>();
+        contents->SetEndPoints(ToPoint(info.fPoint[0]),
+                               ToPoint(info.fPoint[1]));
+        std::vector<Color> colors;
+        for (auto i = 0; i < info.fColorCount; i++) {
+          colors.emplace_back(ToColor(sk_colors[i]));
+        }
+        contents->SetColors(std::move(colors));
+        paint_.contents = std::move(contents);
+        return;
+      } break;
+      case SkShader::kNone_GradientType:
+      case SkShader::kColor_GradientType:
+      case SkShader::kRadial_GradientType:
+      case SkShader::kSweep_GradientType:
+      case SkShader::kConical_GradientType:
+      default:
+        UNIMPLEMENTED;
+        break;
+    }
+  }
+
   // Needs https://github.com/flutter/flutter/issues/95434
   UNIMPLEMENTED;
 }
@@ -154,9 +205,8 @@ static std::optional<Rect> ToRect(const SkRect* rect) {
 // |flutter::Dispatcher|
 void DisplayListDispatcher::saveLayer(const SkRect* bounds,
                                       const flutter::SaveLayerOptions options) {
-  canvas_.SaveLayer(
-    options.renders_with_attributes() ? paint_ : Paint{},
-    ToRect(bounds));
+  canvas_.SaveLayer(options.renders_with_attributes() ? paint_ : Paint{},
+                    ToRect(bounds));
 }
 
 // |flutter::Dispatcher|
@@ -242,10 +292,6 @@ void DisplayListDispatcher::clipRect(const SkRect& rect,
   canvas_.ClipPath(std::move(path));
 }
 
-static Point ToPoint(const SkVector& vector) {
-  return {vector.fX, vector.fY};
-}
-
 static PathBuilder::RoundingRadii ToRoundingRadii(const SkRRect& rrect) {
   using Corner = SkRRect::Corner;
   PathBuilder::RoundingRadii radii;

diff --git a/impeller/entity/BUILD.gn b/impeller/entity/BUILD.gn
@@ -16,6 +16,8 @@ impeller_shaders("entity_shaders") {
     "shaders/solid_stroke.vert",
     "shaders/texture_fill.frag",
     "shaders/texture_fill.vert",
+    "shaders/glyph_atlas.frag",
+    "shaders/glyph_atlas.vert",
   ]
 }
 
@@ -38,6 +40,7 @@ impeller_component("entity") {
     "../archivist",
     "../image",
     "../renderer",
+    "../typographer",
   ]
 }
 

diff --git a/impeller/entity/content_context.cc b/impeller/entity/content_context.cc
@@ -21,6 +21,7 @@ ContentContext::ContentContext(std::shared_ptr<Context> context)
   texture_pipelines_[{}] = std::make_unique<TexturePipeline>(*context_);
   solid_stroke_pipelines_[{}] =
       std::make_unique<SolidStrokePipeline>(*context_);
+  glyph_atlas_pipelines_[{}] = std::make_unique<GlyphAtlasPipeline>(*context_);
 
   // Pipelines that are variants of the base pipelines with custom descriptors.
   // TODO(98684): Rework this API to allow fetching the descriptor without

diff --git a/impeller/entity/content_context.h b/impeller/entity/content_context.h
@@ -9,6 +9,8 @@
 
 #include "flutter/fml/hash_combine.h"
 #include "flutter/fml/macros.h"
+#include "flutter/impeller/entity/glyph_atlas.frag.h"
+#include "flutter/impeller/entity/glyph_atlas.vert.h"
 #include "flutter/impeller/entity/gradient_fill.frag.h"
 #include "flutter/impeller/entity/gradient_fill.vert.h"
 #include "flutter/impeller/entity/solid_fill.frag.h"
@@ -29,6 +31,8 @@ using TexturePipeline =
     PipelineT<TextureFillVertexShader, TextureFillFragmentShader>;
 using SolidStrokePipeline =
     PipelineT<SolidStrokeVertexShader, SolidStrokeFragmentShader>;
+using GlyphAtlasPipeline =
+    PipelineT<GlyphAtlasVertexShader, GlyphAtlasFragmentShader>;
 // Instead of requiring new shaders for clips,  the solid fill stages are used
 // to redirect writing to the stencil instead of color attachments.
 using ClipPipeline = PipelineT<SolidFillVertexShader, SolidFillFragmentShader>;
@@ -81,6 +85,10 @@ class ContentContext {
     return GetPipeline(clip_restoration_pipelines_, opts);
   }
 
+  std::shared_ptr<Pipeline> GetGlyphAtlasPipeline(Options opts) const {
+    return GetPipeline(glyph_atlas_pipelines_, opts);
+  }
+
   std::shared_ptr<Context> GetContext() const;
 
  private:
@@ -99,6 +107,7 @@ class ContentContext {
   mutable Variants<SolidStrokePipeline> solid_stroke_pipelines_;
   mutable Variants<ClipPipeline> clip_pipelines_;
   mutable Variants<ClipPipeline> clip_restoration_pipelines_;
+  mutable Variants<GlyphAtlasPipeline> glyph_atlas_pipelines_;
 
   static void ApplyOptionsToDescriptor(PipelineDescriptor& desc,
                                        const Options& options) {