Implement impeller::DisplayListDispatcher::drawTextBlob. (flutter#94)

Author: chinmaygarde

impeller/aiks/aiks_unittests.cc

@@ -347,19 +347,10 @@ bool RenderTextInCanvas(std::shared_ptr<Context> context,
 
   // Create the Impeller text frame and draw it at the designated baseline.
   auto frame = TextFrameFromTextBlob(blob);
-  TextRenderContextSkia text_context(context);
-  if (!text_context.IsValid()) {
-    return false;
-  }
-  auto atlas = text_context.CreateGlyphAtlas(frame);
-  if (!atlas) {
-    return false;
-  }
 
   Paint text_paint;
   text_paint.color = Color::Yellow();
-  canvas.DrawTextFrame(std::move(frame), std::move(atlas), text_position,
-                       text_paint);
+  canvas.DrawTextFrame(std::move(frame), text_position, text_paint);
   return true;
 }
 

impeller/aiks/canvas.cc

@@ -269,17 +269,14 @@ 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,
-                           Paint paint) {
-  if (!atlas || !atlas->IsValid()) {
-    return;
-  }
+void Canvas::DrawTextFrame(TextFrame text_frame, Point position, Paint paint) {
+  auto lazy_glyph_atlas = GetCurrentPass().GetLazyGlyphAtlas();
+
+  lazy_glyph_atlas->AddTextFrame(std::move(text_frame));
 
   auto text_contents = std::make_shared<TextContents>();
   text_contents->SetTextFrame(std::move(text_frame));
-  text_contents->SetGlyphAtlas(std::move(atlas));
+  text_contents->SetGlyphAtlas(std::move(lazy_glyph_atlas));
   text_contents->SetColor(paint.color.Premultiply());
 
   Entity entity;

impeller/aiks/canvas.h

@@ -78,10 +78,7 @@ class Canvas {
 
   void DrawPicture(Picture picture);
 
-  void DrawTextFrame(TextFrame text_frame,
-                     std::shared_ptr<GlyphAtlas> atlas,
-                     Point position,
-                     Paint paint);
+  void DrawTextFrame(TextFrame text_frame, Point position, Paint paint);
 
   Picture EndRecordingAsPicture();
 

impeller/display_list/BUILD.gn

@@ -10,7 +10,7 @@ impeller_component("display_list") {
     "display_list_dispatcher.h",
   ]
 
-  deps = [
+  public_deps = [
     "../aiks",
     "//flutter/display_list",
     "//flutter/fml",
@@ -21,7 +21,11 @@ impeller_component("display_list") {
 impeller_component("display_list_unittests") {
   testonly = true
 
-  sources = [ "display_list_unittests.cc" ]
+  sources = [
+    "display_list_playground.cc",
+    "display_list_playground.h",
+    "display_list_unittests.cc",
+  ]
 
   deps = [
     ":display_list",

impeller/display_list/display_list_dispatcher.cc

@@ -454,7 +454,8 @@ void DisplayListDispatcher::clipPath(const SkPath& path,
 }
 
 // |flutter::Dispatcher|
-void DisplayListDispatcher::drawColor(SkColor color, flutter::DlBlendMode dl_mode) {
+void DisplayListDispatcher::drawColor(SkColor color,
+                                      flutter::DlBlendMode dl_mode) {
   Paint paint;
   paint.color = ToColor(color);
   if (auto mode = ToBlendMode(dl_mode); mode.has_value()) {
@@ -608,7 +609,10 @@ void DisplayListDispatcher::drawDisplayList(
 void DisplayListDispatcher::drawTextBlob(const sk_sp<SkTextBlob> blob,
                                          SkScalar x,
                                          SkScalar y) {
-  UNIMPLEMENTED;
+  canvas_.DrawTextFrame(TextFrameFromTextBlob(blob),  //
+                        impeller::Point{x, y},        //
+                        paint_                        //
+  );
 }
 
 // |flutter::Dispatcher|

impeller/display_list/display_list_playground.cc

@@ -0,0 +1,71 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "impeller/display_list/display_list_playground.h"
+
+#include "flutter/testing/testing.h"
+#include "impeller/aiks/aiks_context.h"
+#include "impeller/display_list/display_list_dispatcher.h"
+#include "third_party/skia/include/core/SkData.h"
+
+namespace impeller {
+
+DisplayListPlayground::DisplayListPlayground() = default;
+
+DisplayListPlayground::~DisplayListPlayground() = default;
+
+bool DisplayListPlayground::OpenPlaygroundHere(
+    flutter::DisplayListBuilder& builder) {
+  return OpenPlaygroundHere(builder.Build());
+}
+
+bool DisplayListPlayground::OpenPlaygroundHere(
+    sk_sp<flutter::DisplayList> list) {
+  if (!Playground::is_enabled()) {
+    return true;
+  }
+
+  if (!list) {
+    return false;
+  }
+
+  DisplayListDispatcher dispatcher;
+  list->Dispatch(dispatcher);
+  auto picture = dispatcher.EndRecordingAsPicture();
+
+  AiksContext context(GetContext());
+  if (!context.IsValid()) {
+    return false;
+  }
+  return Playground::OpenPlaygroundHere(
+      [&picture, &context](RenderPass& pass) -> bool {
+        return context.Render(picture, pass);
+      });
+}
+
+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());
+}
+
+SkFont DisplayListPlayground::CreateTestFontOfSize(SkScalar scalar) {
+  static constexpr const char* kTestFontFixture = "Roboto-Regular.ttf";
+  auto mapping = OpenFixtureAsSkData(kTestFontFixture);
+  FML_CHECK(mapping);
+  return SkFont{SkTypeface::MakeFromData(mapping), scalar};
+}
+
+SkFont DisplayListPlayground::CreateTestFont() {
+  return CreateTestFontOfSize(50);
+}
+
+}  // namespace impeller

impeller/display_list/display_list_playground.h

@@ -0,0 +1,33 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#pragma once
+
+#include "flutter/display_list/display_list.h"
+#include "flutter/display_list/display_list_builder.h"
+#include "flutter/fml/macros.h"
+#include "impeller/playground/playground.h"
+#include "third_party/skia/include/core/SkFont.h"
+
+namespace impeller {
+
+class DisplayListPlayground : public Playground {
+ public:
+  DisplayListPlayground();
+
+  ~DisplayListPlayground();
+
+  bool OpenPlaygroundHere(flutter::DisplayListBuilder& builder);
+
+  bool OpenPlaygroundHere(sk_sp<flutter::DisplayList> list);
+
+  SkFont CreateTestFontOfSize(SkScalar scalar);
+
+  SkFont CreateTestFont();
+
+ private:
+  FML_DISALLOW_COPY_AND_ASSIGN(DisplayListPlayground);
+};
+
+}  // namespace impeller

impeller/display_list/display_list_unittests.cc

@@ -2,12 +2,29 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "flutter/display_list/display_list_builder.h"
 #include "flutter/testing/testing.h"
+#include "impeller/display_list/display_list_playground.h"
 
 namespace impeller {
 namespace testing {
 
-TEST(DisplayListTest, CanCreateDisatcher) {}
+using DisplayListTest = DisplayListPlayground;
+
+TEST_F(DisplayListTest, CanDrawRect) {
+  flutter::DisplayListBuilder builder;
+  builder.setColor(SK_ColorBLUE);
+  builder.drawRect(SkRect::MakeXYWH(10, 10, 100, 100));
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
+TEST_F(DisplayListTest, CanDrawTextBlob) {
+  flutter::DisplayListBuilder builder;
+  builder.setColor(SK_ColorBLUE);
+  builder.drawTextBlob(SkTextBlob::MakeFromString("Hello", CreateTestFont()),
+                       100, 100);
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
 
 }  // namespace testing
 }  // namespace impeller

impeller/entity/contents/text_contents.cc

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "text_contents.h"
+#include "impeller/entity/contents/text_contents.h"
 
 #include "impeller/entity/contents/content_context.h"
 #include "impeller/entity/entity.h"
@@ -11,8 +11,10 @@
 #include "impeller/renderer/sampler_library.h"
 #include "impeller/tessellator/tessellator.h"
 #include "impeller/typographer/glyph_atlas.h"
+#include "impeller/typographer/lazy_glyph_atlas.h"
 
 namespace impeller {
+
 TextContents::TextContents() = default;
 
 TextContents::~TextContents() = default;
@@ -25,6 +27,23 @@ void TextContents::SetGlyphAtlas(std::shared_ptr<GlyphAtlas> atlas) {
   atlas_ = std::move(atlas);
 }
 
+void TextContents::SetGlyphAtlas(std::shared_ptr<LazyGlyphAtlas> atlas) {
+  atlas_ = std::move(atlas);
+}
+
+std::shared_ptr<GlyphAtlas> TextContents::ResolveAtlas(
+    std::shared_ptr<Context> context) const {
+  if (auto lazy_atlas = std::get_if<std::shared_ptr<LazyGlyphAtlas>>(&atlas_)) {
+    return lazy_atlas->get()->CreateOrGetGlyphAtlas(context);
+  }
+
+  if (auto atlas = std::get_if<std::shared_ptr<GlyphAtlas>>(&atlas_)) {
+    return *atlas;
+  }
+
+  return nullptr;
+}
+
 void TextContents::SetColor(Color color) {
   color_ = color;
 }
@@ -36,7 +55,9 @@ bool TextContents::Render(const ContentContext& renderer,
     return true;
   }
 
-  if (!atlas_ || !atlas_->IsValid()) {
+  auto atlas = ResolveAtlas(renderer.GetContext());
+
+  if (!atlas || !atlas->IsValid()) {
     VALIDATION_LOG << "Cannot render glyphs without prepared atlas.";
     return false;
   }
@@ -57,15 +78,15 @@ bool TextContents::Render(const ContentContext& renderer,
   frame_info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize()) *
                    entity.GetTransformation();
   frame_info.atlas_size =
-      Point{static_cast<Scalar>(atlas_->GetTexture()->GetSize().width),
-            static_cast<Scalar>(atlas_->GetTexture()->GetSize().height)};
+      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.
   FS::BindGlyphAtlasSampler(
       cmd,                                                        // command
-      atlas_->GetTexture(),                                       // texture
+      atlas->GetTexture(),                                        // texture
       renderer.GetContext()->GetSamplerLibrary()->GetSampler({})  // sampler
   );
 
@@ -107,7 +128,7 @@ bool TextContents::Render(const ContentContext& renderer,
     // Draw each glyph individually. This should probably be batched.
     for (const auto& glyph_position : run.GetGlyphPositions()) {
       FontGlyphPair font_glyph_pair{font, glyph_position.glyph};
-      auto atlas_glyph_pos = atlas_->FindFontGlyphPosition(font_glyph_pair);
+      auto atlas_glyph_pos = atlas->FindFontGlyphPosition(font_glyph_pair);
       if (!atlas_glyph_pos.has_value()) {
         VALIDATION_LOG << "Could not find glyph position in the atlas.";
         return false;

impeller/entity/contents/text_contents.h

@@ -6,6 +6,7 @@
 
 #include <functional>
 #include <memory>
+#include <variant>
 #include <vector>
 
 #include "flutter/fml/macros.h"
@@ -16,6 +17,8 @@
 namespace impeller {
 
 class GlyphAtlas;
+class LazyGlyphAtlas;
+class Context;
 
 class TextContents final : public Contents {
  public:
@@ -27,6 +30,8 @@ class TextContents final : public Contents {
 
   void SetGlyphAtlas(std::shared_ptr<GlyphAtlas> atlas);
 
+  void SetGlyphAtlas(std::shared_ptr<LazyGlyphAtlas> atlas);
+
   void SetColor(Color color);
 
   // |Contents|
@@ -37,7 +42,12 @@ class TextContents final : public Contents {
  private:
   TextFrame frame_;
   Color color_;
-  std::shared_ptr<GlyphAtlas> atlas_;
+  mutable std::variant<std::shared_ptr<GlyphAtlas>,
+                       std::shared_ptr<LazyGlyphAtlas>>
+      atlas_;
+
+  std::shared_ptr<GlyphAtlas> ResolveAtlas(
+      std::shared_ptr<Context> context) const;
 
   FML_DISALLOW_COPY_AND_ASSIGN(TextContents);
 };

impeller/entity/entity_pass.cc

@@ -44,6 +44,10 @@ size_t EntityPass::GetSubpassesDepth() const {
   return max_subpass_depth + 1u;
 }
 
+const std::shared_ptr<LazyGlyphAtlas>& EntityPass::GetLazyGlyphAtlas() const {
+  return lazy_glyph_atlas_;
+}
+
 std::optional<Rect> EntityPass::GetEntitiesCoverage() const {
   std::optional<Rect> result;
   for (const auto& entity : entities_) {

impeller/entity/entity_pass.h

@@ -13,6 +13,7 @@
 #include "impeller/entity/entity.h"
 #include "impeller/entity/entity_pass_delegate.h"
 #include "impeller/renderer/render_target.h"
+#include "impeller/typographer/lazy_glyph_atlas.h"
 
 namespace impeller {
 
@@ -41,6 +42,8 @@ class EntityPass {
 
   const Subpasses& GetSubpasses() const;
 
+  const std::shared_ptr<LazyGlyphAtlas>& GetLazyGlyphAtlas() const;
+
   EntityPass* AddSubpass(std::unique_ptr<EntityPass> pass);
 
   EntityPass* GetSuperpass() const;
@@ -61,6 +64,8 @@ class EntityPass {
   size_t stencil_depth_ = 0u;
   std::unique_ptr<EntityPassDelegate> delegate_ =
       EntityPassDelegate::MakeDefault();
+  std::shared_ptr<LazyGlyphAtlas> lazy_glyph_atlas_ =
+      std::make_shared<LazyGlyphAtlas>();
 
   std::optional<Rect> GetSubpassCoverage(const EntityPass& subpass) const;