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* Copyright (C) 2014 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <SkMatrix.h>
#include <SkPath.h>
#include <SkRegion.h>
#include "Snapshot.h"
namespace android {
namespace uirenderer {
* Abstract base class for any class containing CanvasState.
* Defines three mandatory callbacks.
class CanvasStateClient {
CanvasStateClient() { }
virtual ~CanvasStateClient() { }
* Callback allowing embedder to take actions in the middle of a
* setViewport() call.
virtual void onViewportInitialized() = 0;
* Callback allowing embedder to take actions in the middle of a
* restore() call. May be called several times sequentially.
virtual void onSnapshotRestored(const Snapshot& removed, const Snapshot& restored) = 0;
* Allows subclasses to control what value is stored in snapshot's
* fbo field in * initializeSaveStack.
virtual GLuint getTargetFbo() const = 0;
}; // class CanvasStateClient
* Implements Canvas state methods on behalf of Renderers.
* Manages the Snapshot stack, implementing matrix, save/restore, and clipping methods in the
* Renderer interface. Drawing and recording classes that include a CanvasState will have
* different use cases:
* Drawing code maintaining canvas state (i.e. OpenGLRenderer) can query attributes (such as
* transform) or hook into changes (e.g. save/restore) with minimal surface area for manipulating
* the stack itself.
* Recording code maintaining canvas state (i.e. DisplayListCanvas) can both record and pass
* through state operations to CanvasState, so that not only will querying operations work
* (getClip/Matrix), but so that quickRejection can also be used.
class CanvasState {
CanvasState(CanvasStateClient& renderer);
* Initializes the first snapshot, computing the projection matrix,
* and stores the dimensions of the render target.
void initializeSaveStack(int viewportWidth, int viewportHeight,
float clipLeft, float clipTop, float clipRight, float clipBottom,
const Vector3& lightCenter);
bool hasRectToRectTransform() const {
return CC_LIKELY(currentTransform()->rectToRect());
// Save (layer)
int getSaveCount() const { return mSaveCount; }
int save(int flags);
void restore();
void restoreToCount(int saveCount);
// Save/Restore without side-effects
int saveSnapshot(int flags);
void restoreSnapshot();
// Matrix
void getMatrix(SkMatrix* outMatrix) const;
void translate(float dx, float dy, float dz = 0.0f);
void rotate(float degrees);
void scale(float sx, float sy);
void skew(float sx, float sy);
void setMatrix(const SkMatrix& matrix);
void setMatrix(const Matrix4& matrix); // internal only convenience method
void concatMatrix(const SkMatrix& matrix);
void concatMatrix(const Matrix4& matrix); // internal only convenience method
// Clip
const Rect& getLocalClipBounds() const { return mSnapshot->getLocalClip(); }
const Rect& getRenderTargetClipBounds() const { return mSnapshot->getRenderTargetClip(); }
bool quickRejectConservative(float left, float top, float right, float bottom) const;
bool clipRect(float left, float top, float right, float bottom, SkRegion::Op op);
bool clipPath(const SkPath* path, SkRegion::Op op);
bool clipRegion(const SkRegion* region, SkRegion::Op op);
* Sets a "clipping outline", which is independent from the regular clip.
* Currently only supports rectangles or rounded rectangles; passing in a
* more complicated outline fails silently. Replaces any previous clipping
* outline.
void setClippingOutline(LinearAllocator& allocator, const Outline* outline);
void setClippingRoundRect(LinearAllocator& allocator,
const Rect& rect, float radius, bool highPriority = true);
void setProjectionPathMask(LinearAllocator& allocator, const SkPath* path);
* Returns true if drawing in the rectangle (left, top, right, bottom)
* will be clipped out. Is conservative: might return false when subpixel-
* perfect tests would return true.
bool calculateQuickRejectForScissor(float left, float top, float right, float bottom,
bool* clipRequired, bool* roundRectClipRequired, bool snapOut) const;
void setDirtyClip(bool opaque) { mDirtyClip = opaque; }
bool getDirtyClip() const { return mDirtyClip; }
void scaleAlpha(float alpha) { mSnapshot->alpha *= alpha; }
void setEmpty(bool value) { mSnapshot->empty = value; }
void setInvisible(bool value) { mSnapshot->invisible = value; }
inline const mat4* currentTransform() const { return currentSnapshot()->transform; }
inline const Rect& currentClipRect() const { return currentSnapshot()->getClipRect(); }
inline Region* currentRegion() const { return currentSnapshot()->region; }
inline int currentFlags() const { return currentSnapshot()->flags; }
const Vector3& currentLightCenter() const { return currentSnapshot()->getRelativeLightCenter(); }
inline bool currentlyIgnored() const { return currentSnapshot()->isIgnored(); }
int getViewportWidth() const { return currentSnapshot()->getViewportWidth(); }
int getViewportHeight() const { return currentSnapshot()->getViewportHeight(); }
int getWidth() const { return mWidth; }
int getHeight() const { return mHeight; }
bool clipIsSimple() const { return currentSnapshot()->clipIsSimple(); }
inline const Snapshot* currentSnapshot() const { return mSnapshot.get(); }
inline Snapshot* writableSnapshot() { return mSnapshot.get(); }
inline const Snapshot* firstSnapshot() const { return mFirstSnapshot.get(); }
/// indicates that the clip has been changed since the last time it was consumed
bool mDirtyClip;
/// Dimensions of the drawing surface
int mWidth, mHeight;
/// Number of saved states
int mSaveCount;
/// Base state
sp<Snapshot> mFirstSnapshot;
/// Host providing callbacks
CanvasStateClient& mCanvas;
/// Current state
sp<Snapshot> mSnapshot;
}; // class CanvasState
}; // namespace uirenderer
}; // namespace android