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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_HWUI_CANVAS_STATE_H
     18 #define ANDROID_HWUI_CANVAS_STATE_H
     19 
     20 #include "Snapshot.h"
     21 
     22 #include <SkMatrix.h>
     23 #include <SkPath.h>
     24 #include <SkRegion.h>
     25 
     26 namespace android {
     27 namespace uirenderer {
     28 
     29 /**
     30  * Abstract base class for any class containing CanvasState.
     31  * Defines three mandatory callbacks.
     32  */
     33 class CanvasStateClient {
     34 public:
     35     CanvasStateClient() { }
     36     virtual ~CanvasStateClient() { }
     37 
     38     /**
     39      * Callback allowing embedder to take actions in the middle of a
     40      * setViewport() call.
     41      */
     42     virtual void onViewportInitialized() = 0;
     43 
     44     /**
     45      * Callback allowing embedder to take actions in the middle of a
     46      * restore() call.  May be called several times sequentially.
     47      */
     48     virtual void onSnapshotRestored(const Snapshot& removed, const Snapshot& restored) = 0;
     49 
     50     /**
     51      * Allows subclasses to control what value is stored in snapshot's
     52      * fbo field in * initializeSaveStack.
     53      */
     54     virtual GLuint getTargetFbo() const = 0;
     55 
     56 }; // class CanvasStateClient
     57 
     58 /**
     59  * Implements Canvas state methods on behalf of Renderers.
     60  *
     61  * Manages the Snapshot stack, implementing matrix, save/restore, and clipping methods in the
     62  * Renderer interface. Drawing and recording classes that include a CanvasState will have
     63  * different use cases:
     64  *
     65  * Drawing code maintaining canvas state (i.e. OpenGLRenderer) can query attributes (such as
     66  * transform) or hook into changes (e.g. save/restore) with minimal surface area for manipulating
     67  * the stack itself.
     68  *
     69  * Recording code maintaining canvas state (i.e. DisplayListCanvas) can both record and pass
     70  * through state operations to CanvasState, so that not only will querying operations work
     71  * (getClip/Matrix), but so that quickRejection can also be used.
     72  */
     73 
     74 class CanvasState {
     75 public:
     76     CanvasState(CanvasStateClient& renderer);
     77     ~CanvasState();
     78 
     79     /**
     80      * Initializes the first snapshot, computing the projection matrix,
     81      * and stores the dimensions of the render target.
     82      */
     83     void initializeRecordingSaveStack(int viewportWidth, int viewportHeight);
     84 
     85     /**
     86      * Initializes the first snapshot, computing the projection matrix,
     87      * and stores the dimensions of the render target.
     88      */
     89     void initializeSaveStack(int viewportWidth, int viewportHeight,
     90             float clipLeft, float clipTop, float clipRight, float clipBottom,
     91             const Vector3& lightCenter);
     92 
     93     bool hasRectToRectTransform() const {
     94         return CC_LIKELY(currentTransform()->rectToRect());
     95     }
     96 
     97     // Save (layer)
     98     int getSaveCount() const { return mSaveCount; }
     99     int save(int flags);
    100     void restore();
    101     void restoreToCount(int saveCount);
    102 
    103     // Save/Restore without side-effects
    104     int saveSnapshot(int flags);
    105     void restoreSnapshot();
    106 
    107     // Matrix
    108     void getMatrix(SkMatrix* outMatrix) const;
    109     void translate(float dx, float dy, float dz = 0.0f);
    110     void rotate(float degrees);
    111     void scale(float sx, float sy);
    112     void skew(float sx, float sy);
    113 
    114     void setMatrix(const SkMatrix& matrix);
    115     void setMatrix(const Matrix4& matrix); // internal only convenience method
    116     void concatMatrix(const SkMatrix& matrix);
    117     void concatMatrix(const Matrix4& matrix); // internal only convenience method
    118 
    119     // Clip
    120     const Rect& getLocalClipBounds() const { return mSnapshot->getLocalClip(); }
    121     const Rect& getRenderTargetClipBounds() const { return mSnapshot->getRenderTargetClip(); }
    122 
    123     bool quickRejectConservative(float left, float top, float right, float bottom) const;
    124 
    125     bool clipRect(float left, float top, float right, float bottom, SkRegion::Op op);
    126     bool clipPath(const SkPath* path, SkRegion::Op op);
    127     bool clipRegion(const SkRegion* region, SkRegion::Op op);
    128 
    129     /**
    130      * Sets a "clipping outline", which is independent from the regular clip.
    131      * Currently only supports rectangles or rounded rectangles; passing in a
    132      * more complicated outline fails silently. Replaces any previous clipping
    133      * outline.
    134      */
    135     void setClippingOutline(LinearAllocator& allocator, const Outline* outline);
    136     void setClippingRoundRect(LinearAllocator& allocator,
    137             const Rect& rect, float radius, bool highPriority = true);
    138     void setProjectionPathMask(LinearAllocator& allocator, const SkPath* path);
    139 
    140     /**
    141      * Returns true if drawing in the rectangle (left, top, right, bottom)
    142      * will be clipped out. Is conservative: might return false when subpixel-
    143      * perfect tests would return true.
    144      */
    145     bool calculateQuickRejectForScissor(float left, float top, float right, float bottom,
    146             bool* clipRequired, bool* roundRectClipRequired, bool snapOut) const;
    147 
    148     void setDirtyClip(bool opaque) { mDirtyClip = opaque; }
    149     bool getDirtyClip() const { return mDirtyClip; }
    150 
    151     void scaleAlpha(float alpha) { mSnapshot->alpha *= alpha; }
    152     void setEmpty(bool value) { mSnapshot->empty = value; }
    153     void setInvisible(bool value) { mSnapshot->invisible = value; }
    154 
    155     inline const mat4* currentTransform() const { return currentSnapshot()->transform; }
    156     inline const Rect& currentRenderTargetClip() const { return currentSnapshot()->getRenderTargetClip(); }
    157     inline Region* currentRegion() const { return currentSnapshot()->region; }
    158     inline int currentFlags() const { return currentSnapshot()->flags; }
    159     const Vector3& currentLightCenter() const { return currentSnapshot()->getRelativeLightCenter(); }
    160     inline bool currentlyIgnored() const { return currentSnapshot()->isIgnored(); }
    161     int getViewportWidth() const { return currentSnapshot()->getViewportWidth(); }
    162     int getViewportHeight() const { return currentSnapshot()->getViewportHeight(); }
    163     int getWidth() const { return mWidth; }
    164     int getHeight() const { return mHeight; }
    165     bool clipIsSimple() const { return currentSnapshot()->clipIsSimple(); }
    166 
    167     inline const Snapshot* currentSnapshot() const { return mSnapshot; }
    168     inline Snapshot* writableSnapshot() { return mSnapshot; }
    169     inline const Snapshot* firstSnapshot() const { return &mFirstSnapshot; }
    170 
    171 private:
    172     Snapshot* allocSnapshot(Snapshot* previous, int savecount);
    173     void freeSnapshot(Snapshot* snapshot);
    174     void freeAllSnapshots();
    175 
    176     /// indicates that the clip has been changed since the last time it was consumed
    177     // TODO: delete when switching to HWUI_NEW_OPS
    178     bool mDirtyClip;
    179 
    180     /// Dimensions of the drawing surface
    181     int mWidth, mHeight;
    182 
    183     /// Number of saved states
    184     int mSaveCount;
    185 
    186     /// Base state
    187     Snapshot mFirstSnapshot;
    188 
    189     /// Host providing callbacks
    190     CanvasStateClient& mCanvas;
    191 
    192     /// Current state
    193     Snapshot* mSnapshot;
    194 
    195     // Pool of allocated snapshots to re-use
    196     // NOTE: The dtors have already been invoked!
    197     Snapshot* mSnapshotPool = nullptr;
    198     int mSnapshotPoolCount = 0;
    199 
    200 }; // class CanvasState
    201 
    202 }; // namespace uirenderer
    203 }; // namespace android
    204 
    205 #endif // ANDROID_HWUI_CANVAS_STATE_H
    206