pdfviewer: All NulCanvas (does not draw operations), TrackDevice (trackes what pixels have been cha…

experimental/PdfViewer/SkNulCanvas.h

+#ifndef EXPERIMENTAL_PDFVIEWER_SKNULCANVAS_H_
+#define EXPERIMENTAL_PDFVIEWER_SKNULCANVAS_H_
+
+#include "SkCanvas.h"
+
+class SK_API SkNulCanvas : public SkCanvas {
+public:
+    SK_DECLARE_INST_COUNT(SkNulCanvas);
+
+    SkNulCanvas() {}
+    explicit SkNulCanvas(SkDevice* device) : SkCanvas(device) {}
+
+    explicit SkNulCanvas(const SkBitmap& bitmap) : SkCanvas(bitmap) {}
+    virtual ~SkNulCanvas() {}
+
+    virtual int save(SaveFlags flags = kMatrixClip_SaveFlag) {return 0;}
+    virtual int saveLayer(const SkRect* bounds, const SkPaint* paint,
+                          SaveFlags flags = kARGB_ClipLayer_SaveFlag) {return 0;}
+    int saveLayerAlpha(const SkRect* bounds, U8CPU alpha,
+                       SaveFlags flags = kARGB_ClipLayer_SaveFlag) {return 0;}
+    virtual void restore() {}
+    int getSaveCount() const {return 0;}
+    virtual bool isDrawingToLayer() const {return false;}
+    virtual bool translate(SkScalar dx, SkScalar dy) {return true;}
+    virtual bool scale(SkScalar sx, SkScalar sy) {return true;}
+    virtual bool rotate(SkScalar degrees) {return true;}
+    virtual bool skew(SkScalar sx, SkScalar sy) {return true;}
+    virtual bool concat(const SkMatrix& matrix) {return true;}
+    virtual void setMatrix(const SkMatrix& matrix) {}
+    virtual bool clipRect(const SkRect& rect,
+                          SkRegion::Op op = SkRegion::kIntersect_Op,
+                          bool doAntiAlias = false) {return true;}
+    virtual bool clipRRect(const SkRRect& rrect,
+                           SkRegion::Op op = SkRegion::kIntersect_Op,
+                           bool doAntiAlias = false) {return true;}
+    virtual bool clipPath(const SkPath& path,
+                          SkRegion::Op op = SkRegion::kIntersect_Op,
+                          bool doAntiAlias = false) {return true;}
+    virtual bool clipRegion(const SkRegion& deviceRgn,
+                            SkRegion::Op op = SkRegion::kIntersect_Op) {return true;}
+    virtual void clear(SkColor) {}
+    virtual void drawPaint(const SkPaint& paint) {}
+    virtual void drawPoints(PointMode mode, size_t count, const SkPoint pts[],
+                            const SkPaint& paint) {}
+    virtual void drawRect(const SkRect& rect, const SkPaint& paint) {}
+    virtual void drawOval(const SkRect& oval, const SkPaint&) {}
+    virtual void drawRRect(const SkRRect& rrect, const SkPaint& paint) {}
+    virtual void drawPath(const SkPath& path, const SkPaint& paint) {}
+    virtual void drawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
+                            const SkPaint* paint = NULL) {}
+    virtual void drawBitmapRectToRect(const SkBitmap& bitmap, const SkRect* src,
+                                      const SkRect& dst,
+                                      const SkPaint* paint) {}
+    virtual void drawBitmapMatrix(const SkBitmap& bitmap, const SkMatrix& m,
+                                  const SkPaint* paint = NULL) {}
+    virtual void drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
+                                const SkRect& dst, const SkPaint* paint = NULL) {}
+    virtual void drawSprite(const SkBitmap& bitmap, int left, int top,
+                            const SkPaint* paint = NULL) {}
+    virtual void drawText(const void* text, size_t byteLength, SkScalar x,
+                          SkScalar y, const SkPaint& paint) {}
+    virtual void drawPosText(const void* text, size_t byteLength,
+                             const SkPoint pos[], const SkPaint& paint) {}
+    virtual void drawPosTextH(const void* text, size_t byteLength,
+                              const SkScalar xpos[], SkScalar constY,
+                              const SkPaint& paint) {}
+    virtual void drawTextOnPath(const void* text, size_t byteLength,
+                                const SkPath& path, const SkMatrix* matrix,
+                                const SkPaint& paint) {}
+    virtual void drawPicture(SkPicture& picture) {}
+    virtual void drawVertices(VertexMode vmode, int vertexCount,
+                              const SkPoint vertices[], const SkPoint texs[],
+                              const SkColor colors[], SkXfermode* xmode,
+                              const uint16_t indices[], int indexCount,
+                              const SkPaint& paint) {}
+    virtual void drawData(const void* data, size_t length) {}
+    virtual void beginCommentGroup(const char* description) {}
+    virtual void addComment(const char* kywd, const char* value) {}
+    virtual void endCommentGroup() {}
+    virtual SkBounder* setBounder(SkBounder* bounder) {return NULL;}
+    virtual SkDrawFilter* setDrawFilter(SkDrawFilter* filter) {return NULL;}
+
+protected:
+    virtual SkCanvas* canvasForDrawIter() {return NULL;}
+    virtual SkDevice* setDevice(SkDevice* device) {return NULL;}
+
+private:
+    typedef SkCanvas INHERITED;
+};
+
+#endif  // EXPERIMENTAL_PDFVIEWER_SKNULCANVAS_H_