Add option to skip rects to drawImageLattice()

gm/lattice.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkSurface.h"
 
@@ skipping 95 matching lines @@
         canvas->drawImage(image, 10, 10, nullptr);
 
         SkScalar x = SkIntToScalar(100);
         SkScalar y = SkIntToScalar(100);
 
         SkCanvas::Lattice lattice;
         lattice.fXCount = 4;
         lattice.fXDivs = xDivs + 1;
         lattice.fYCount = 4;
         lattice.fYDivs = yDivs + 1;
+        lattice.fFlags = nullptr;
 
         for (int iy = 0; iy < 2; ++iy) {
             for (int ix = 0; ix < 2; ++ix) {
                 int i = ix * 2 + iy;
                 SkRect r = SkRect::MakeXYWH(x + ix * 60, y + iy * 60,
                                             size[i].width(), size[i].height());
                 canvas->drawBitmapLattice(bitmap, lattice, r);
             }
         }
 
         // Include the degenerate first div.  While normally the first patch is "scalable",
         // this will mean that the first non-degenerate patch is "fixed".
         lattice.fXCount = 5;
         lattice.fXDivs = xDivs;
         lattice.fYCount = 5;
         lattice.fYDivs = yDivs;
 
+        // Let's skip a few rects.
+        SkCanvas::Lattice::Flags flags[36];
+        sk_bzero(flags, 36 * sizeof(SkCanvas::Lattice::Flags));
+        flags[4] = SkCanvas::Lattice::kTransparent_Flags;
+        flags[9] = SkCanvas::Lattice::kTransparent_Flags;
+        flags[12] = SkCanvas::Lattice::kTransparent_Flags;
+        flags[19] = SkCanvas::Lattice::kTransparent_Flags;
+        lattice.fFlags = flags;
+
         canvas->translate(400, 0);
         for (int iy = 0; iy < 2; ++iy) {
             for (int ix = 0; ix < 2; ++ix) {
                 int i = ix * 2 + iy;
                 SkRect r = SkRect::MakeXYWH(x + ix * 60, y + iy * 60,
                                             size[i].width(), size[i].height());
                 canvas->drawImageLattice(image.get(), lattice, r);
             }
         }
     }
 
 private:
     typedef skiagm::GM INHERITED;
 };
 DEF_GM( return new LatticeGM; )