Initial support for turning Skia draws into a JSON document and vice versa.

tools/json/SkJSONCanvas.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkJSONCanvas_DEFINED
+#define SkJSONCanvas_DEFINED
+
+#include "SkCanvas.h"
+#include "SkStream.h"
+
+#define SKJSONCANVAS_VERSION                     "version"
+#define SKJSONCANVAS_COMMANDS                    "commands"
+#define SKJSONCANVAS_COMMAND                     "command"
+
+#define SKJSONCANVAS_COMMAND_MATRIX              "Matrix"
+#define SKJSONCANVAS_COMMAND_PAINT               "Paint"
+#define SKJSONCANVAS_COMMAND_RECT                "Rect"
+#define SKJSONCANVAS_COMMAND_OVAL                "Oval"
+#define SKJSONCANVAS_COMMAND_RRECT               "RRect"
+#define SKJSONCANVAS_COMMAND_DRRECT              "DRRect"
+#define SKJSONCANVAS_COMMAND_POINTS              "Points"
+#define SKJSONCANVAS_COMMAND_VERTICES            "Vertices"
+#define SKJSONCANVAS_COMMAND_ATLAS               "Atlas"
+#define SKJSONCANVAS_COMMAND_PATH                "Path"
+#define SKJSONCANVAS_COMMAND_IMAGE               "Image"
+#define SKJSONCANVAS_COMMAND_IMAGERECT           "ImageRect"
+#define SKJSONCANVAS_COMMAND_IMAGENINE           "ImageNine"
+#define SKJSONCANVAS_COMMAND_BITMAP              "Bitmap"
+#define SKJSONCANVAS_COMMAND_BITMAPRECT          "BitmapRect"
+#define SKJSONCANVAS_COMMAND_BITMAPNINE          "BitmapNine"
+#define SKJSONCANVAS_COMMAND_TEXT                "Text"
+#define SKJSONCANVAS_COMMAND_POSTEXT             "PosText"
+#define SKJSONCANVAS_COMMAND_POSTEXTH            "PosTextH"
+#define SKJSONCANVAS_COMMAND_TEXTONPATH          "TextOnPath"
+#define SKJSONCANVAS_COMMAND_TEXTBLOB            "TextBlob"
+#define SKJSONCANVAS_COMMAND_PATCH               "Patch"
+#define SKJSONCANVAS_COMMAND_DRAWABLE            "Drawable"
+#define SKJSONCANVAS_COMMAND_CLIPRECT            "ClipRect"
+#define SKJSONCANVAS_COMMAND_CLIPRRECT           "ClipRRect"
+#define SKJSONCANVAS_COMMAND_CLIPPATH            "ClipPath"
+#define SKJSONCANVAS_COMMAND_CLIPREGION          "ClipRegion"
+#define SKJSONCANVAS_COMMAND_SAVE                "Save"
+#define SKJSONCANVAS_COMMAND_RESTORE             "Restore"
+
+#define SKJSONCANVAS_ATTRIBUTE_MATRIX            "matrix"
+#define SKJSONCANVAS_ATTRIBUTE_COORDS            "coords"
+#define SKJSONCANVAS_ATTRIBUTE_PAINT             "paint"
+#define SKJSONCANVAS_ATTRIBUTE_OUTER             "outer"
+#define SKJSONCANVAS_ATTRIBUTE_INNER             "inner"
+#define SKJSONCANVAS_ATTRIBUTE_MODE              "mode"
+#define SKJSONCANVAS_ATTRIBUTE_POINTS            "points"
+#define SKJSONCANVAS_ATTRIBUTE_PATH              "path"
+#define SKJSONCANVAS_ATTRIBUTE_TEXT              "text"
+#define SKJSONCANVAS_ATTRIBUTE_COLOR             "color"
+#define SKJSONCANVAS_ATTRIBUTE_STYLE             "style"
+#define SKJSONCANVAS_ATTRIBUTE_STROKEWIDTH       "strokeWidth"
+#define SKJSONCANVAS_ATTRIBUTE_ANTIALIAS         "antiAlias"
+#define SKJSONCANVAS_ATTRIBUTE_REGIONOP          "op"
+#define SKJSONCANVAS_ATTRIBUTE_EDGESTYLE         "edgeStyle"
+#define SKJSONCANVAS_ATTRIBUTE_DEVICEREGION      "deviceRegion"
+
+#define SKJSONCANVAS_VERB_MOVE                   "move"
+#define SKJSONCANVAS_VERB_LINE                   "line"
+#define SKJSONCANVAS_VERB_QUAD                   "quad"
+#define SKJSONCANVAS_VERB_CUBIC                  "cubic"
+#define SKJSONCANVAS_VERB_CONIC                  "conic"
+#define SKJSONCANVAS_VERB_CLOSE                  "close"
+
+#define SKJSONCANVAS_STYLE_FILL                  "fill"
+#define SKJSONCANVAS_STYLE_STROKE                "stroke"
+#define SKJSONCANVAS_STYLE_STROKEANDFILL         "strokeAndFill"
+
+#define SKJSONCANVAS_EDGESTYLE_HARD              "hard"
+#define SKJSONCANVAS_EDGESTYLE_SOFT              "soft"
+
+#define SKJSONCANVAS_POINTMODE_POINTS            "points"
+#define SKJSONCANVAS_POINTMODE_LINES             "lines"
+#define SKJSONCANVAS_POINTMODE_POLYGON           "polygon"
+
+#define SKJSONCANVAS_REGIONOP_DIFFERENCE         "difference"
+#define SKJSONCANVAS_REGIONOP_INTERSECT          "intersect"
+#define SKJSONCANVAS_REGIONOP_UNION              "union"
+#define SKJSONCANVAS_REGIONOP_XOR                "xor"
+#define SKJSONCANVAS_REGIONOP_REVERSE_DIFFERENCE "reverseDifference"
+#define SKJSONCANVAS_REGIONOP_REPLACE            "replace"
+
+/* 
+ * Implementation of SkCanvas which writes JSON when drawn to. The JSON describes all of the draw
+ * commands issued to the canvas, and can later be turned back into draw commands using 
+ * SkJSONRenderer. Be sure to call finish() when you are done drawing.
+ */
+class SkJSONCanvas : public SkCanvas {
+public:
+    /* Create a canvas which writes to the specified output stream. */
+    SkJSONCanvas(int width, int height, SkWStream& out);
+
+    /* Complete the JSON document. */
+    void finish();
+
+    // overridden SkCanvas API
+
+    void onDrawPaint(const SkPaint&) override;
+
+    void onDrawRect(const SkRect&, const SkPaint&) override;
+
+    void onDrawOval(const SkRect&, const SkPaint&) override;
+
+    void onDrawRRect(const SkRRect&, const SkPaint&) override;
+
+    void onDrawDRRect(const SkRRect&, const SkRRect&, const SkPaint&) override;
+
+    void onDrawPoints(SkCanvas::PointMode, size_t count, const SkPoint pts[], 
+                      const SkPaint&) override;
+
+    void onDrawVertices(SkCanvas::VertexMode, int vertexCount, const SkPoint vertices[],
+                        const SkPoint texs[], const SkColor colors[], SkXfermode*,
+                        const uint16_t indices[], int indexCount, const SkPaint&) override;
+
+    void onDrawAtlas(const SkImage*, const SkRSXform[], const SkRect[], const SkColor[],
+                     int count, SkXfermode::Mode, const SkRect* cull, const SkPaint*) override;
+
+    void onDrawPath(const SkPath&, const SkPaint&) override;
+
+    void onDrawImage(const SkImage*, SkScalar dx, SkScalar dy, const SkPaint*) override;
+
+    void onDrawImageRect(const SkImage*, const SkRect*, const SkRect&, const SkPaint*,
+                         SrcRectConstraint) override;
+
+    void onDrawImageNine(const SkImage*, const SkIRect& center, const SkRect& dst,
+                         const SkPaint*) override;
+
+    void onDrawBitmap(const SkBitmap&, SkScalar dx, SkScalar dy, const SkPaint*) override;
+
+    void onDrawBitmapRect(const SkBitmap&, const SkRect*, const SkRect&, const SkPaint*,
+                          SkCanvas::SrcRectConstraint) override;
+
+    void onDrawBitmapNine(const SkBitmap&, const SkIRect& center, const SkRect& dst,
+                          const SkPaint*) override;
+
+    void onDrawText(const void* text, size_t byteLength, SkScalar x,
+                    SkScalar y, const SkPaint& paint) override;
+
+    void onDrawPosText(const void* text, size_t byteLength,
+                       const SkPoint pos[], const SkPaint& paint) override;
+
+    void onDrawPosTextH(const void* text, size_t byteLength,
+                        const SkScalar xpos[], SkScalar constY,
+                        const SkPaint& paint) override;
+
+    void onDrawTextOnPath(const void* text, size_t byteLength,
+                          const SkPath& path, const SkMatrix* matrix,
+                          const SkPaint& paint) override;
+
+    void onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
+                        const SkPaint& paint) override;
+
+    void onDrawPatch(const SkPoint cubics[12], const SkColor colors[4],
+                     const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint) override;
+
+    void onDrawDrawable(SkDrawable*, const SkMatrix*) override;    
+
+    void onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle edgeStyle) override;
+
+    void onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle) override;
+
+    void onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle) override;
+
+    void onClipRegion(const SkRegion& deviceRgn, SkRegion::Op op) override;
+
+    void willSave() override;
+
+    void willRestore() override;
+
+private:
+    void writef(const char* fmt, ...);
+
+    void open(const char* name);
+
+    void close();
+
+    void writeString(const char* name, const char* text);
+
+    void writeString(const char* name, const void* text, size_t length);
+
+    void writePoint(const char* name, const SkPoint& point);
+
+    void writeRect(const char* name, const SkRect& rect);
+
+    void writeRRect(const char* name, const SkRRect& rrect);
+
+    void writePath(const char* name, const SkPath& path);
+
+    void writeRegion(const char* name, const SkRegion& region);
+  
+    void writePaint(const SkPaint& paint);
+  
+    void writeRegionOp(const char* name, SkRegion::Op op);
+  
+    void writeEdgeStyle(const char* name, SkCanvas::ClipEdgeStyle edgeStyle);
+  
+    void writePointMode(const char* name, SkCanvas::PointMode mode);
+  
+    void writeMatrix(const char* name, const SkMatrix& matrix);
+  
+    void updateMatrix();
+
+    SkWStream& fOut;
+    SkMatrix   fLastMatrix;
+    bool       fFirstCommand;
+
+    typedef SkCanvas INHERITED;
+};
+
+#endif