Relay text color from Paint. (flutter#43)

impeller/aiks/aiks_unittests.cc

@@ -299,9 +299,11 @@ static sk_sp<SkData> OpenFixtureAsSkData(const char* fixture_name) {
       mapping.release());
 }
 
-TEST_F(AiksTest, CanRenderTextFrame) {
-  Canvas canvas;
-
+bool RenderTextInCanvas(std::shared_ptr<Context> context,
+                        Canvas& canvas,
+                        const std::string& text,
+                        const std::string& font_fixture,
+                        Scalar font_size = 50.0) {
   Scalar baseline = 200.0;
   Point text_position = {100, baseline};
 
@@ -314,84 +316,56 @@ TEST_F(AiksTest, CanRenderTextFrame) {
                     Paint{.color = Color::Red().WithAlpha(0.25)});
 
   // Construct the text blob.
-  auto mapping = OpenFixtureAsSkData("Roboto-Regular.ttf");
-  ASSERT_TRUE(mapping);
+  auto mapping = OpenFixtureAsSkData(font_fixture.c_str());
+  if (!mapping) {
+    return false;
+  }
   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);
+  auto blob = SkTextBlob::MakeFromString(text.c_str(), sk_font);
+  if (!blob) {
+    return false;
+  }
 
   // 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());
+  TextRenderContextSkia text_context(context);
+  if (!text_context.IsValid()) {
+    return false;
+  }
   auto atlas = text_context.CreateGlyphAtlas(frame);
-  ASSERT_NE(atlas, nullptr);
-  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position);
+  if (!atlas) {
+    return false;
+  }
+
+  Paint text_paint;
+  text_paint.color = Color::Yellow();
+  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position,
+                       text_paint);
+  return true;
+}
+
+TEST_F(AiksTest, CanRenderTextFrame) {
+  Canvas canvas;
+  ASSERT_TRUE(RenderTextInCanvas(
+      GetContext(), canvas, "the quick brown fox jumped over the lazy dog!.?",
+      "Roboto-Regular.ttf"));
   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(RenderTextInCanvas(
+      GetContext(), canvas, "the quick brown fox jumped over the lazy dog!.?",
+      "HomemadeApple.ttf"));
   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(RenderTextInCanvas(
+      GetContext(), canvas,
+      "😀 😃 😄 😁 😆 😅 😂 🤣 🥲 ☺️ 😊",
+      "NotoColorEmoji.ttf"));
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 

impeller/aiks/canvas.cc

@@ -254,14 +254,16 @@ void Canvas::Save(bool create_subpass) {
 
 void Canvas::DrawTextFrame(TextFrame text_frame,
                            std::shared_ptr<GlyphAtlas> atlas,
-                           Point position) {
+                           Point position,
+                           Paint paint) {
   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));
+  text_contents->SetColor(paint.color);
 
   Entity entity;
   entity.SetTransformation(GetCurrentTransformation() *

impeller/aiks/canvas.h

@@ -77,7 +77,8 @@ class Canvas {
 
   void DrawTextFrame(TextFrame text_frame,
                      std::shared_ptr<GlyphAtlas> atlas,
-                     Point position);
+                     Point position,
+                     Paint paint);
 
   Picture EndRecordingAsPicture();
 

impeller/entity/contents.cc

@@ -568,9 +568,17 @@ void TextContents::SetGlyphAtlas(std::shared_ptr<GlyphAtlas> atlas) {
   atlas_ = std::move(atlas);
 }
 
+void TextContents::SetColor(Color color) {
+  color_ = color;
+}
+
 bool TextContents::Render(const ContentContext& renderer,
                           const Entity& entity,
                           RenderPass& pass) const {
+  if (color_.IsTransparent()) {
+    return true;
+  }
+
   if (!atlas_ || !atlas_->IsValid()) {
     VALIDATION_LOG << "Cannot render glyphs without prepared atlas.";
     return false;
@@ -593,6 +601,7 @@ bool TextContents::Render(const ContentContext& renderer,
   frame_info.atlas_size =
       Point{static_cast<Scalar>(atlas_->GetTexture()->GetSize().width),
             static_cast<Scalar>(atlas_->GetTexture()->GetSize().height)};
+  frame_info.text_color = ToVector(color_);
   VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(frame_info));
 
   // Common fragment uniforms for all glyphs.

impeller/entity/contents.h

@@ -210,13 +210,16 @@ class TextContents final : public Contents {
 
   void SetGlyphAtlas(std::shared_ptr<GlyphAtlas> atlas);
 
+  void SetColor(Color color);
+
   // |Contents|
   bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
  private:
   TextFrame frame_;
+  Color color_;
   std::shared_ptr<GlyphAtlas> atlas_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(TextContents);

impeller/entity/shaders/glyph_atlas.frag

@@ -8,6 +8,7 @@ in vec2 v_unit_vertex;
 in vec2 v_atlas_position;
 in vec2 v_atlas_glyph_size;
 in vec2 v_atlas_size;
+in vec4 v_text_color;
 
 out vec4 frag_color;
 
@@ -18,5 +19,5 @@ void main() {
   frag_color = texture(
     glyph_atlas_sampler,
     v_unit_vertex * scale_perspective + offset
-  );
+  ) * v_text_color;
 }

impeller/entity/shaders/glyph_atlas.vert

@@ -5,6 +5,7 @@
 uniform FrameInfo {
   mat4 mvp;
   vec2 atlas_size;
+  vec4 text_color;
 } frame_info;
 
 uniform GlyphInfo {
@@ -20,6 +21,7 @@ out vec2 v_unit_vertex;
 out vec2 v_atlas_position;
 out vec2 v_atlas_glyph_size;
 out vec2 v_atlas_size;
+out vec4 v_text_color;
 
 void main() {
   mat4 scale = mat4(
@@ -37,4 +39,5 @@ void main() {
   v_atlas_position = glyph_info.atlas_position;
   v_atlas_glyph_size = glyph_info.atlas_glyph_size;
   v_atlas_size = frame_info.atlas_size;
+  v_text_color = frame_info.text_color;
 }

impeller/renderer/shader_types.h

@@ -94,4 +94,8 @@ struct Padding {
   uint8_t pad_[Size];
 };
 
+inline constexpr Vector4 ToVector(Color color) {
+  return {color.red, color.green, color.blue, color.alpha};
+}
+
 }  // namespace impeller