Add option to skip rects to drawImageLattice()

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 916 matching lines @@
      *  - The corners shrink proportionally
      *  - The sides (along the shrink axis) and center are not drawn
      */
     void drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center, const SkRect& dst,
                         const SkPaint* paint = NULL);
 
     /**
      *  Specifies coordinates to divide a bitmap into (xCount*yCount) rects.
      */
     struct Lattice {
+        enum Flags : uint8_t {
+            // If set, indicates that we should not draw corresponding rect.
+            kSkip_Flags = 1 << 0,
+        };
+
         // An array of x-coordinates that divide the bitmap vertically.
         // These must be unique, increasing, and in the set [0, width].
         // Does not have ownership.
-        const int* fXDivs;
+        const int*   fXDivs;
 
         // The number of fXDivs.
-        int        fXCount;
+        int          fXCount;
 
         // An array of y-coordinates that divide the bitmap horizontally.
         // These must be unique, increasing, and in the set [0, height].
         // Does not have ownership.
-        const int* fYDivs;
+        const int*   fYDivs;
 
         // The number of fYDivs.
-        int        fYCount;
+        int          fYCount;
+
+        // If non-null, the length of this array must be equal to the total
+        // number of rects specified in the lattice. The flags correspond
+        // to the rects in the lattice, first moving left to right and then
+        // top to bottom.
+        const Flags* fFlags;
+
+        // The number of fFlags.  Must be equal to the total number of rects
+        // specified in the lattice, or flags will be ignored.  If fFlags is
+        // null, this should be set to zero.
+        int          fFlagCount;

[reed1, 2016/09/01 14:15:23]

Lets try not having this, and just documenting that fFlags must be (xdivs +
1)*(ydivs + 1) long...?

[msarett, 2016/09/01 16:27:24]

SGTM

     };
 
     /**
      *  Draw the bitmap stretched or shrunk differentially to fit into dst.
      *
      *  Moving horizontally across the bitmap, alternating rects will be "scalable"
      *  (in the x-dimension) to fit into dst or must be left "fixed".  The first rect
      *  is treated as "fixed", but it's possible to specify an empty first rect by
      *  making lattice.fXDivs[0] = 0.
      *
@@ skipping 755 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif