lib/ui/compositing.dart - mirrors/engine - Git at Google

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 part of dart_ui;

 /// An opaque object representing a composited scene.
 ///
 /// To create a Scene object, use a [SceneBuilder].
 ///
 /// Scene objects can be displayed on the screen using the
 /// [Window.render] method.
 class Scene extends NativeFieldWrapperClass2 {
   /// Creates an uninitialized Scene object.
   ///
   /// Calling the Scene constructor directly will not create a useable
   /// object. To create a Scene object, use a [SceneBuilder].
   Scene(); // (this constructor is here just so we can document it)

   /// Releases the resources used by this scene.
   ///
   /// After calling this function, the scene is cannot be used further.
   void dispose() native "Scene_dispose";
 }

 /// Builds a [Scene] containing the given visuals.
 ///
 /// A [Scene] can then be rendered using [Window.render].
 ///
 /// To draw graphical operations onto a [Scene], first create a
 /// [Picture] using a [PictureRecorder] and a [Canvas], and then add
 /// it to the scene using [addPicture].
 class SceneBuilder extends NativeFieldWrapperClass2 {
   /// Creates an empty [SceneBuilder] object.
   SceneBuilder() { _constructor(); }
   void _constructor() native "SceneBuilder_constructor";

   /// Pushes a transform operation onto the operation stack.
   ///
   /// The objects are transformed by the given matrix before rasterization.
   ///
   /// See [pop] for details about the operation stack.
   void pushTransform(Float64List matrix4) {
     if (matrix4 == null)
       throw new ArgumentError("[matrix4] argument cannot be null");
     if (matrix4.length != 16)
       throw new ArgumentError("[matrix4] must have 16 entries.");
     _pushTransform(matrix4);
   }
   void _pushTransform(Float64List matrix4) native "SceneBuilder_pushTransform";

   /// Pushes a rectangular clip operation onto the operation stack.
   ///
   /// Rasterization outside the given rectangle is discarded.
   ///
   /// See [pop] for details about the operation stack.
   void pushClipRect(Rect rect) {
     _pushClipRect(rect.left, rect.right, rect.top, rect.bottom);
   }
   void _pushClipRect(double left,
                      double right,
                      double top,
                      double bottom) native "SceneBuilder_pushClipRect";

   /// Pushes a rounded-rectangular clip operation onto the operation stack.
   ///
   /// Rasterization outside the given rounded rectangle is discarded.
   ///
   /// See [pop] for details about the operation stack.
   void pushClipRRect(RRect rrect) => _pushClipRRect(rrect._value);
   void _pushClipRRect(Float32List rrect) native "SceneBuilder_pushClipRRect";

   /// Pushes a path clip operation onto the operation stack.
   ///
   /// Rasterization outside the given path is discarded.
   ///
   /// See [pop] for details about the operation stack.
   void pushClipPath(Path path) native "SceneBuilder_pushClipPath";

   /// Pushes an opacity operation onto the operation stack.
   ///
   /// The given alpha value is blended into the alpha value of the objects'
   /// rasterization. An alpha value of 0 makes the objects entirely invisible.
   /// An alpha value of 255 has no effect (i.e., the objects retain the current
   /// opacity).
   ///
   /// See [pop] for details about the operation stack.
   void pushOpacity(int alpha) native "SceneBuilder_pushOpacity";

   /// Pushes a color filter operation onto the operation stack.
   ///
   /// The given color is applied to the objects' rasterization using the given
   /// blend mode.
   ///
   /// See [pop] for details about the operation stack.
   void pushColorFilter(Color color, BlendMode blendMode) {
     _pushColorFilter(color.value, blendMode.index);
   }
   void _pushColorFilter(int color, int blendMode) native "SceneBuilder_pushColorFilter";

   /// Pushes a backdrop filter operation onto the operation stack.
   ///
   /// The given filter is applied to the current contents of the scene prior to
   /// rasterizing the given objects.
   ///
   /// See [pop] for details about the operation stack.
   void pushBackdropFilter(ImageFilter filter) native "SceneBuilder_pushBackdropFilter";

   /// Pushes a shader mask operation onto the operation stack.
   ///
   /// The given shader is applied to the object's rasterization in the given
   /// rectangle using the given blend mode.
   ///
   /// See [pop] for details about the operation stack.
   void pushShaderMask(Shader shader, Rect maskRect, BlendMode blendMode) {
     _pushShaderMask(shader,
                     maskRect.left,
                     maskRect.right,
                     maskRect.top,
                     maskRect.bottom,
                     blendMode.index);
   }
   void _pushShaderMask(Shader shader,
                        double maskRectLeft,
                        double maskRectRight,
                        double maskRectTop,
                        double maskRectBottom,
                        int blendMode) native "SceneBuilder_pushShaderMask";

   /// Ends the effect of the most recently pushed operation.
   ///
   /// Internally the scene builder maintains a stack of operations. Each of the
   /// operations in the stack applies to each of the objects added to the scene.
   /// Calling this function removes the most recently added operation from the
   /// stack.
   void pop() native "SceneBuilder_pop";

   /// Adds an object to the scene that displays performance statistics.
   ///
   /// Useful during development to assess the performance of the application.
   /// The enabledOptions controls which statistics are displayed. The bounds
   /// controls where the statistics are displayed.
   ///
   /// enabledOptions is a bit field with the following bits defined:
   ///  - 0x01: displayRasterizerStatistics - show GPU thread frame time
   ///  - 0x02: visualizeRasterizerStatistics - graph GPU thread frame times
   ///  - 0x04: displayEngineStatistics - show UI thread frame time
   ///  - 0x08: visualizeEngineStatistics - graph UI thread frame times
   /// Set enabledOptions to 0x0F to enable all the currently defined features.
   ///
   /// The "UI thread" is the thread that includes all the execution of
   /// the main Dart isolate (the isolate that can call
   /// [Window.render]). The UI thread frame time is the total time
   /// spent executing the [Window.onBeginFrame] callback. The "GPU
   /// thread" is the thread (running on the CPU) that subsequently
   /// processes the [Scene] provided by the Dart code to turn it into
   /// GPU commands and send it to the GPU.
   ///
   /// See also the [PerformanceOverlayOption] enum in the rendering library.
   /// for more details.
   // Values above must match constants in //engine/src/sky/compositor/performance_overlay_layer.h
   void addPerformanceOverlay(int enabledOptions, Rect bounds) {
     _addPerformanceOverlay(enabledOptions,
                            bounds.left,
                            bounds.right,
                            bounds.top,
                            bounds.bottom);
   }
   void _addPerformanceOverlay(int enabledOptions,
                               double left,
                               double right,
                               double top,
                               double bottom) native "SceneBuilder_addPerformanceOverlay";

   /// Adds a [Picture] to the scene.
   ///
   /// The picture is rasterized at the given offset.
   void addPicture(Offset offset, Picture picture, { bool isComplexHint: false, bool willChangeHint: false }) {
     int hints = 0;
     if (isComplexHint)
       hints |= 1;
     if (willChangeHint)
       hints |= 2;
     _addPicture(offset.dx, offset.dy, picture, hints);
   }
   void _addPicture(double dx, double dy, Picture picture, int hints) native "SceneBuilder_addPicture";

   /// (Fuchsia-only) Adds a scene rendered by another application to the scene
   /// for this application.
   ///
   /// Applications typically obtain scene tokens when embedding other views via
   /// the Fuchsia view manager, but this function is agnostic as to the source
   /// of scene token.
   void addChildScene({
     Offset offset: Offset.zero,
     double devicePixelRatio: 1.0,
     int physicalWidth: 0,
     int physicalHeight: 0,
     int sceneToken,
     bool hitTestable: true
   }) {
     _addChildScene(offset.dx,
                    offset.dy,
                    devicePixelRatio,
                    physicalWidth,
                    physicalHeight,
                    sceneToken,
                    hitTestable);
   }
   void _addChildScene(double dx,
                       double dy,
                       double devicePixelRatio,
                       int physicalWidth,
                       int physicalHeight,
                       int sceneToken,
                       bool hitTestable) native "SceneBuilder_addChildScene";

   /// Sets a threshold after which additional debugging information should be recorded.
   ///
   /// Currently this interface is difficult to use by end-developers. If you're
   /// interested in using this feature, please contact [flutter-dev](https://groups.google.com/forum/#!forum/flutter-dev).
   /// We'll hopefully be able to figure out how to make this feature more useful
   /// to you.
   void setRasterizerTracingThreshold(int frameInterval) native "SceneBuilder_setRasterizerTracingThreshold";

   /// Sets whether the raster cache should checkerboard cached entries. This is
   /// only useful for debugging purposes.
   ///
   /// The compositor can sometimes decide to cache certain portions of the
   /// widget hierarchy. Such portions typically don't change often from frame to
   /// frame and are expensive to render. This can speed up overall rendering. However,
   /// there is certain upfront cost to constructing these cache entries. And, if
   /// the cache entries are not used very often, this cost may not be worth the
   /// speedup in rendering of subsequent frames. If the developer wants to be certain
   /// that populating the raster cache is not causing stutters, this option can be
   /// set. Depending on the observations made, hints can be provided to the compositor
   /// that aid it in making better decisions about caching.
   ///
   /// Currently this interface is difficult to use by end-developers. If you're
   /// interested in using this feature, please contact [flutter-dev](https://groups.google.com/forum/#!forum/flutter-dev).
   void setCheckerboardRasterCacheImages(bool checkerboard) native "SceneBuilder_setCheckerboardRasterCacheImages";

   /// Finishes building the scene.
   ///
   /// Returns a [Scene] containing the objects that have been added to
   /// this scene builder. The [Scene] can then be displayed on the
   /// screen with [Window.render].
   ///
   /// After calling this function, the scene builder object is invalid and
   /// cannot be used further.
   Scene build() native "SceneBuilder_build";
 }
	// Copyright 2015 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	part of dart_ui;

	/// An opaque object representing a composited scene.
	///
	/// To create a Scene object, use a [SceneBuilder].
	///
	/// Scene objects can be displayed on the screen using the
	/// [Window.render] method.
	class Scene extends NativeFieldWrapperClass2 {
	/// Creates an uninitialized Scene object.
	///
	/// Calling the Scene constructor directly will not create a useable
	/// object. To create a Scene object, use a [SceneBuilder].
	Scene(); // (this constructor is here just so we can document it)

	/// Releases the resources used by this scene.
	///
	/// After calling this function, the scene is cannot be used further.
	void dispose() native "Scene_dispose";
	}

	/// Builds a [Scene] containing the given visuals.
	///
	/// A [Scene] can then be rendered using [Window.render].
	///
	/// To draw graphical operations onto a [Scene], first create a
	/// [Picture] using a [PictureRecorder] and a [Canvas], and then add
	/// it to the scene using [addPicture].
	class SceneBuilder extends NativeFieldWrapperClass2 {
	/// Creates an empty [SceneBuilder] object.
	SceneBuilder() { _constructor(); }
	void _constructor() native "SceneBuilder_constructor";

	/// Pushes a transform operation onto the operation stack.
	///
	/// The objects are transformed by the given matrix before rasterization.
	///
	/// See [pop] for details about the operation stack.
	void pushTransform(Float64List matrix4) {
	if (matrix4 == null)
	throw new ArgumentError("[matrix4] argument cannot be null");
	if (matrix4.length != 16)
	throw new ArgumentError("[matrix4] must have 16 entries.");
	_pushTransform(matrix4);
	}
	void _pushTransform(Float64List matrix4) native "SceneBuilder_pushTransform";

	/// Pushes a rectangular clip operation onto the operation stack.
	///
	/// Rasterization outside the given rectangle is discarded.
	///
	/// See [pop] for details about the operation stack.
	void pushClipRect(Rect rect) {
	_pushClipRect(rect.left, rect.right, rect.top, rect.bottom);
	}
	void _pushClipRect(double left,
	double right,
	double top,
	double bottom) native "SceneBuilder_pushClipRect";

	/// Pushes a rounded-rectangular clip operation onto the operation stack.
	///
	/// Rasterization outside the given rounded rectangle is discarded.
	///
	/// See [pop] for details about the operation stack.
	void pushClipRRect(RRect rrect) => _pushClipRRect(rrect._value);
	void _pushClipRRect(Float32List rrect) native "SceneBuilder_pushClipRRect";

	/// Pushes a path clip operation onto the operation stack.
	///
	/// Rasterization outside the given path is discarded.
	///
	/// See [pop] for details about the operation stack.
	void pushClipPath(Path path) native "SceneBuilder_pushClipPath";

	/// Pushes an opacity operation onto the operation stack.
	///
	/// The given alpha value is blended into the alpha value of the objects'
	/// rasterization. An alpha value of 0 makes the objects entirely invisible.
	/// An alpha value of 255 has no effect (i.e., the objects retain the current
	/// opacity).
	///
	/// See [pop] for details about the operation stack.
	void pushOpacity(int alpha) native "SceneBuilder_pushOpacity";

	/// Pushes a color filter operation onto the operation stack.
	///
	/// The given color is applied to the objects' rasterization using the given
	/// blend mode.
	///
	/// See [pop] for details about the operation stack.
	void pushColorFilter(Color color, BlendMode blendMode) {
	_pushColorFilter(color.value, blendMode.index);
	}
	void _pushColorFilter(int color, int blendMode) native "SceneBuilder_pushColorFilter";

	/// Pushes a backdrop filter operation onto the operation stack.
	///
	/// The given filter is applied to the current contents of the scene prior to
	/// rasterizing the given objects.
	///
	/// See [pop] for details about the operation stack.
	void pushBackdropFilter(ImageFilter filter) native "SceneBuilder_pushBackdropFilter";

	/// Pushes a shader mask operation onto the operation stack.
	///
	/// The given shader is applied to the object's rasterization in the given
	/// rectangle using the given blend mode.
	///
	/// See [pop] for details about the operation stack.
	void pushShaderMask(Shader shader, Rect maskRect, BlendMode blendMode) {
	_pushShaderMask(shader,
	maskRect.left,
	maskRect.right,
	maskRect.top,
	maskRect.bottom,
	blendMode.index);
	}
	void _pushShaderMask(Shader shader,
	double maskRectLeft,
	double maskRectRight,
	double maskRectTop,
	double maskRectBottom,
	int blendMode) native "SceneBuilder_pushShaderMask";

	/// Ends the effect of the most recently pushed operation.
	///
	/// Internally the scene builder maintains a stack of operations. Each of the
	/// operations in the stack applies to each of the objects added to the scene.
	/// Calling this function removes the most recently added operation from the
	/// stack.
	void pop() native "SceneBuilder_pop";

	/// Adds an object to the scene that displays performance statistics.
	///
	/// Useful during development to assess the performance of the application.
	/// The enabledOptions controls which statistics are displayed. The bounds
	/// controls where the statistics are displayed.
	///
	/// enabledOptions is a bit field with the following bits defined:
	/// - 0x01: displayRasterizerStatistics - show GPU thread frame time
	/// - 0x02: visualizeRasterizerStatistics - graph GPU thread frame times
	/// - 0x04: displayEngineStatistics - show UI thread frame time
	/// - 0x08: visualizeEngineStatistics - graph UI thread frame times
	/// Set enabledOptions to 0x0F to enable all the currently defined features.
	///
	/// The "UI thread" is the thread that includes all the execution of
	/// the main Dart isolate (the isolate that can call
	/// [Window.render]). The UI thread frame time is the total time
	/// spent executing the [Window.onBeginFrame] callback. The "GPU
	/// thread" is the thread (running on the CPU) that subsequently
	/// processes the [Scene] provided by the Dart code to turn it into
	/// GPU commands and send it to the GPU.
	///
	/// See also the [PerformanceOverlayOption] enum in the rendering library.
	/// for more details.
	// Values above must match constants in //engine/src/sky/compositor/performance_overlay_layer.h
	void addPerformanceOverlay(int enabledOptions, Rect bounds) {
	_addPerformanceOverlay(enabledOptions,
	bounds.left,
	bounds.right,
	bounds.top,
	bounds.bottom);
	}
	void _addPerformanceOverlay(int enabledOptions,
	double left,
	double right,
	double top,
	double bottom) native "SceneBuilder_addPerformanceOverlay";

	/// Adds a [Picture] to the scene.
	///
	/// The picture is rasterized at the given offset.
	void addPicture(Offset offset, Picture picture, { bool isComplexHint: false, bool willChangeHint: false }) {
	int hints = 0;
	if (isComplexHint)
	hints \|= 1;
	if (willChangeHint)
	hints \|= 2;
	_addPicture(offset.dx, offset.dy, picture, hints);
	}
	void _addPicture(double dx, double dy, Picture picture, int hints) native "SceneBuilder_addPicture";

	/// (Fuchsia-only) Adds a scene rendered by another application to the scene
	/// for this application.
	///
	/// Applications typically obtain scene tokens when embedding other views via
	/// the Fuchsia view manager, but this function is agnostic as to the source
	/// of scene token.
	void addChildScene({
	Offset offset: Offset.zero,
	double devicePixelRatio: 1.0,
	int physicalWidth: 0,
	int physicalHeight: 0,
	int sceneToken,
	bool hitTestable: true
	}) {
	_addChildScene(offset.dx,
	offset.dy,
	devicePixelRatio,
	physicalWidth,
	physicalHeight,
	sceneToken,
	hitTestable);
	}
	void _addChildScene(double dx,
	double dy,
	double devicePixelRatio,
	int physicalWidth,
	int physicalHeight,
	int sceneToken,
	bool hitTestable) native "SceneBuilder_addChildScene";

	/// Sets a threshold after which additional debugging information should be recorded.
	///
	/// Currently this interface is difficult to use by end-developers. If you're
	/// interested in using this feature, please contact [flutter-dev](https://groups.google.com/forum/#!forum/flutter-dev).
	/// We'll hopefully be able to figure out how to make this feature more useful
	/// to you.
	void setRasterizerTracingThreshold(int frameInterval) native "SceneBuilder_setRasterizerTracingThreshold";

	/// Sets whether the raster cache should checkerboard cached entries. This is
	/// only useful for debugging purposes.
	///
	/// The compositor can sometimes decide to cache certain portions of the
	/// widget hierarchy. Such portions typically don't change often from frame to
	/// frame and are expensive to render. This can speed up overall rendering. However,
	/// there is certain upfront cost to constructing these cache entries. And, if
	/// the cache entries are not used very often, this cost may not be worth the
	/// speedup in rendering of subsequent frames. If the developer wants to be certain
	/// that populating the raster cache is not causing stutters, this option can be
	/// set. Depending on the observations made, hints can be provided to the compositor
	/// that aid it in making better decisions about caching.
	///
	/// Currently this interface is difficult to use by end-developers. If you're
	/// interested in using this feature, please contact [flutter-dev](https://groups.google.com/forum/#!forum/flutter-dev).
	void setCheckerboardRasterCacheImages(bool checkerboard) native "SceneBuilder_setCheckerboardRasterCacheImages";

	/// Finishes building the scene.
	///
	/// Returns a [Scene] containing the objects that have been added to
	/// this scene builder. The [Scene] can then be displayed on the
	/// screen with [Window.render].
	///
	/// After calling this function, the scene builder object is invalid and
	/// cannot be used further.
	Scene build() native "SceneBuilder_build";
	}