Allow freezing a texture. (flutter#5938)

This is needed to avoid jank when resizing an embedded Android view. See flutter#19572 (comment)
liyuqian · Aug 7, 2018 · 7e0bb3b · 7e0bb3b
1 parent 3cbb5e2
commit 7e0bb3b
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Showing 13 changed files with 52 additions and 28 deletions.
diff --git a/flow/layers/default_layer_builder.cc b/flow/layers/default_layer_builder.cc
@@ -163,14 +163,16 @@ void DefaultLayerBuilder::PushPicture(const SkPoint& offset,
 
 void DefaultLayerBuilder::PushTexture(const SkPoint& offset,
                                       const SkSize& size,
-                                      int64_t texture_id) {
+                                      int64_t texture_id,
+                                      bool freeze) {
   if (!current_layer_) {
     return;
   }
   auto layer = std::make_unique<flow::TextureLayer>();
   layer->set_offset(offset);
   layer->set_size(size);
   layer->set_texture_id(texture_id);
+  layer->set_freeze(freeze);
   current_layer_->Add(std::move(layer));
 }
 

diff --git a/flow/layers/default_layer_builder.h b/flow/layers/default_layer_builder.h
@@ -70,7 +70,8 @@ class DefaultLayerBuilder final : public LayerBuilder {
   // |flow::LayerBuilder|
   void PushTexture(const SkPoint& offset,
                    const SkSize& size,
-                   int64_t texture_id) override;
+                   int64_t texture_id,
+                   bool freeze) override;
 
 #if defined(OS_FUCHSIA)
   // |flow::LayerBuilder|

diff --git a/flow/layers/layer_builder.h b/flow/layers/layer_builder.h
@@ -68,7 +68,8 @@ class LayerBuilder {
 
   virtual void PushTexture(const SkPoint& offset,
                            const SkSize& size,
-                           int64_t texture_id) = 0;
+                           int64_t texture_id,
+                           bool freeze) = 0;
 
 #if defined(OS_FUCHSIA)
   virtual void PushChildScene(

diff --git a/flow/layers/texture_layer.cc b/flow/layers/texture_layer.cc
@@ -23,7 +23,7 @@ void TextureLayer::Paint(PaintContext& context) const {
   if (!texture) {
     return;
   }
-  texture->Paint(context.canvas, paint_bounds());
+  texture->Paint(context.canvas, paint_bounds(), freeze_);
 }
 
 }  // namespace flow
diff --git a/flow/layers/texture_layer.h b/flow/layers/texture_layer.h
@@ -22,6 +22,7 @@ class TextureLayer : public Layer {
   void set_offset(const SkPoint& offset) { offset_ = offset; }
   void set_size(const SkSize& size) { size_ = size; }
   void set_texture_id(int64_t texture_id) { texture_id_ = texture_id; }
+  void set_freeze(bool freeze) { freeze_ = freeze; }
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
   void Paint(PaintContext& context) const override;
@@ -30,6 +31,7 @@ class TextureLayer : public Layer {
   SkPoint offset_;
   SkSize size_;
   int64_t texture_id_;
+  bool freeze_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(TextureLayer);
 };

diff --git a/flow/texture.h b/flow/texture.h
@@ -22,7 +22,7 @@ class Texture {
   virtual ~Texture();
 
   // Called from GPU thread.
-  virtual void Paint(SkCanvas& canvas, const SkRect& bounds) = 0;
+  virtual void Paint(SkCanvas& canvas, const SkRect& bounds, bool freeze) = 0;
 
   // Called from GPU thread.
   virtual void OnGrContextCreated() = 0;

diff --git a/lib/ui/compositing.dart b/lib/ui/compositing.dart
@@ -235,11 +235,19 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   /// Adds a backend texture to the scene.
   ///
   /// The texture is scaled to the given size and rasterized at the given offset.
-  void addTexture(int textureId, { Offset offset: Offset.zero, double width: 0.0, double height: 0.0 }) {
+  ///
+  /// If `freeze` is true the texture that is added to the scene will not
+  /// be updated with new frames. `freeze` is used when resizing an embedded
+  /// Android view: When resizing an Android view there is a short period during
+  /// which the framework cannot tell if the newest texture frame has the
+  /// previous or new size, to workaround this the framework "freezes" the
+  /// texture just before resizing the Android view and unfreezes it when it is
+  /// certain that a frame with the new size is ready.
+  void addTexture(int textureId, { Offset offset: Offset.zero, double width: 0.0, double height: 0.0 , bool freeze: false}) {
     assert(offset != null, 'Offset argument was null');
-    _addTexture(offset.dx, offset.dy, width, height, textureId);
+    _addTexture(offset.dx, offset.dy, width, height, textureId, freeze);
   }
-  void _addTexture(double dx, double dy, double width, double height, int textureId) native 'SceneBuilder_addTexture';
+  void _addTexture(double dx, double dy, double width, double height, int textureId, bool freeze) native 'SceneBuilder_addTexture';
 
   /// (Fuchsia-only) Adds a scene rendered by another application to the scene
   /// for this application.

diff --git a/lib/ui/compositing/scene_builder.cc b/lib/ui/compositing/scene_builder.cc
@@ -138,9 +138,10 @@ void SceneBuilder::addTexture(double dx,
                               double dy,
                               double width,
                               double height,
-                              int64_t textureId) {
+                              int64_t textureId,
+                              bool freeze) {
   layer_builder_->PushTexture(SkPoint::Make(dx, dy),
-                              SkSize::Make(width, height), textureId);
+                              SkSize::Make(width, height), textureId, freeze);
 }
 
 void SceneBuilder::addChildScene(double dx,

diff --git a/lib/ui/compositing/scene_builder.h b/lib/ui/compositing/scene_builder.h
@@ -70,7 +70,8 @@ class SceneBuilder : public RefCountedDartWrappable<SceneBuilder> {
                   double dy,
                   double width,
                   double height,
-                  int64_t textureId);
+                  int64_t textureId,
+                  bool freeze);
 
   void addChildScene(double dx,
                      double dy,

diff --git a/shell/platform/android/android_external_texture_gl.cc b/shell/platform/android/android_external_texture_gl.cc
@@ -26,7 +26,9 @@ void AndroidExternalTextureGL::MarkNewFrameAvailable() {
   new_frame_ready_ = true;
 }
 
-void AndroidExternalTextureGL::Paint(SkCanvas& canvas, const SkRect& bounds) {
+void AndroidExternalTextureGL::Paint(SkCanvas& canvas,
+                                     const SkRect& bounds,
+                                     bool freeze) {
   if (state_ == AttachmentState::detached) {
     return;
   }
@@ -35,7 +37,7 @@ void AndroidExternalTextureGL::Paint(SkCanvas& canvas, const SkRect& bounds) {
     Attach(static_cast<jint>(texture_name_));
     state_ = AttachmentState::attached;
   }
-  if (new_frame_ready_) {
+  if (!freeze && new_frame_ready_) {
     Update();
     new_frame_ready_ = false;
   }

diff --git a/shell/platform/android/android_external_texture_gl.h b/shell/platform/android/android_external_texture_gl.h
@@ -19,7 +19,9 @@ class AndroidExternalTextureGL : public flow::Texture {
 
   ~AndroidExternalTextureGL() override;
 
-  virtual void Paint(SkCanvas& canvas, const SkRect& bounds) override;
+  virtual void Paint(SkCanvas& canvas,
+                     const SkRect& bounds,
+                     bool freeze) override;
 
   virtual void OnGrContextCreated() override;
 

diff --git a/shell/platform/darwin/ios/ios_external_texture_gl.h b/shell/platform/darwin/ios/ios_external_texture_gl.h
@@ -19,7 +19,9 @@ class IOSExternalTextureGL : public flow::Texture {
   ~IOSExternalTextureGL() override;
 
   // Called from GPU thread.
-  virtual void Paint(SkCanvas& canvas, const SkRect& bounds) override;
+  virtual void Paint(SkCanvas& canvas,
+                     const SkRect& bounds,
+                     bool freeze) override;
 
   virtual void OnGrContextCreated() override;
 

diff --git a/shell/platform/darwin/ios/ios_external_texture_gl.mm b/shell/platform/darwin/ios/ios_external_texture_gl.mm
@@ -24,7 +24,7 @@
 
 IOSExternalTextureGL::~IOSExternalTextureGL() = default;
 
-void IOSExternalTextureGL::Paint(SkCanvas& canvas, const SkRect& bounds) {
+void IOSExternalTextureGL::Paint(SkCanvas& canvas, const SkRect& bounds, bool freeze) {
   if (!cache_ref_) {
     CVOpenGLESTextureCacheRef cache;
     CVReturn err = CVOpenGLESTextureCacheCreate(kCFAllocatorDefault, NULL,
@@ -37,18 +37,20 @@
     }
   }
   fml::CFRef<CVPixelBufferRef> bufferRef;
-  bufferRef.Reset([external_texture_ copyPixelBuffer]);
-  if (bufferRef != nullptr) {
-    CVOpenGLESTextureRef texture;
-    CVReturn err = CVOpenGLESTextureCacheCreateTextureFromImage(
-        kCFAllocatorDefault, cache_ref_, bufferRef, nullptr, GL_TEXTURE_2D, GL_RGBA,
-        static_cast<int>(CVPixelBufferGetWidth(bufferRef)),
-        static_cast<int>(CVPixelBufferGetHeight(bufferRef)), GL_BGRA, GL_UNSIGNED_BYTE, 0,
-        &texture);
-    texture_ref_.Reset(texture);
-    if (err != noErr) {
-      FML_LOG(WARNING) << "Could not create texture from pixel buffer: " << err;
-      return;
+  if (!freeze) {
+    bufferRef.Reset([external_texture_ copyPixelBuffer]);
+    if (bufferRef != nullptr) {
+      CVOpenGLESTextureRef texture;
+      CVReturn err = CVOpenGLESTextureCacheCreateTextureFromImage(
+          kCFAllocatorDefault, cache_ref_, bufferRef, nullptr, GL_TEXTURE_2D, GL_RGBA,
+          static_cast<int>(CVPixelBufferGetWidth(bufferRef)),
+          static_cast<int>(CVPixelBufferGetHeight(bufferRef)), GL_BGRA, GL_UNSIGNED_BYTE, 0,
+          &texture);
+      texture_ref_.Reset(texture);
+      if (err != noErr) {
+        FML_LOG(WARNING) << "Could not create texture from pixel buffer: " << err;
+        return;
+      }
     }
   }
   if (!texture_ref_) {