add Method param to drawTextOnPath, supporting SVG spec

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 0ec167e1166e72870b90440ae31d4ca348a7cec4..55ff4f7ec8ddc554eda23e2dc321b2bd74ce3a1a 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -19,6 +19,17 @@
 #include "SkSurfaceProps.h"
 #include "SkXfermode.h"
 
+#ifdef SK_SUPPORT_LEGACY_DRAWTEXTONPATH
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_PARAM
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_ARG
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_DEFAULT_METHOD \
+        SkCanvas::TextOnPathMethod method = SkCanvas::kStretch_TextOnPathMethod;
+#else
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_PARAM          SkCanvas::TextOnPathMethod method,
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_ARG            method,
+    #define SK_SUPPORT_LEGACY_DRAWTEXTONPATH_DEFAULT_METHOD
+#endif
+
 class SkBaseDevice;
 class SkCanvasClipVisitor;
 class SkDraw;
@@ -909,20 +920,21 @@ public:
     void drawPosTextH(const void* text, size_t byteLength, const SkScalar xpos[], SkScalar constY,
                       const SkPaint& paint);
 
+#ifdef SK_SUPPORT_LEGACY_DRAWTEXTONPATH
     /** Draw the text, with origin at (x,y), using the specified paint, along
         the specified path. The paint's Align setting determins where along the
         path to start the text.
         @param text The text to be drawn
         @param byteLength   The number of bytes to read from the text parameter
         @param path         The path the text should follow for its baseline
-        @param hOffset      The distance along the path to add to the text's
+        @param trangentOffset The distance along the path to add to the text's
                             starting position
-        @param vOffset      The distance above(-) or below(+) the path to
+        @param normalOffset The distance above(-) or below(+) the path to
                             position the text
         @param paint        The paint used for the text
     */
-    void drawTextOnPathHV(const void* text, size_t byteLength, const SkPath& path, SkScalar hOffset,
-                          SkScalar vOffset, const SkPaint& paint);
+    void drawTextOnPathHV(const void* text, size_t byteLength, const SkPath& path,
+                          SkScalar trangentOffset, SkScalar normalOffset, const SkPaint& paint);
 
     /** Draw the text, with origin at (x,y), using the specified paint, along
         the specified path. The paint's Align setting determins where along the
@@ -936,6 +948,26 @@ public:
         */
     void drawTextOnPath(const void* text, size_t byteLength, const SkPath& path,
                         const SkMatrix* matrix, const SkPaint& paint);
+#endif
+
+    enum TextOnPathMethod {
+        kStretch_TextOnPathMethod,  //!< warp the shape of each glyph to match the path
+        kAlign_TextOnPathMethod     //!< rotate each glyph to align with the path's direction
+    };
+
+    /**
+     *  Draw the text, with origin at (x,y), using the specified paint, along
+     *  the specified path. The paint's Align setting determins where along the
+     *  path to start the text.
+     *  @param text The text to be drawn
+     *  @param byteLength   The number of bytes to read from the text parameter
+     *  @param path         The path the text should follow for its baseline
+     *  @param matrix       (may be null) Applied to the text before it is mapped onto the path
+     *  @param method       How to orient/warp each glyph along the path.
+     *  @param paint        The paint used for the text
+     */
+    void drawTextOnPath(const void* text, size_t byteLength, const SkPath& path,
+                        const SkMatrix* matrix, TextOnPathMethod, const SkPaint& paint);
 
     /** Draw the text blob, offset by (x,y), using the specified paint.
         @param blob     The text blob to be drawn
@@ -1188,6 +1220,7 @@ protected:
 
     virtual void onDrawTextOnPath(const void* text, size_t byteLength,
                                   const SkPath& path, const SkMatrix* matrix,
+                                  SK_SUPPORT_LEGACY_DRAWTEXTONPATH_PARAM
                                   const SkPaint& paint);
 
     virtual void onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,