Add option to skip rects to drawImageLattice()

src/core/SkLatticeIter.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLatticeIter.h"
 #include "SkRect.h"
 
@@ skipping 140 matching lines @@
     fDstX.reset(xCount + 2);
     set_points(fDstX.begin(), fSrcX.begin(), xDivs, xCount, xCountFixed, xCountScalable,
                dst.fLeft, dst.fRight, xIsScalable);
 
     fSrcY.reset(yCount + 2);
     fDstY.reset(yCount + 2);
     set_points(fDstY.begin(), fSrcY.begin(), yDivs, yCount, yCountFixed, yCountScalable,
                dst.fTop, dst.fBottom, yIsScalable);
 
     fCurrX = fCurrY = 0;
-    fDone = false;
-    fNumRects = (xCount + 1) * (yCount + 1);
+    fNumRectsInLattice = (xCount + 1) * (yCount + 1);
+    fNumRectsToDraw = fNumRectsInLattice;
+
+    if (lattice.fFlags && fNumRectsInLattice == lattice.fFlagCount) {
+        fFlags.push_back_n(lattice.fFlagCount, lattice.fFlags);
+
+        for (int i = 0; i < lattice.fFlagCount; i++) {
+            if (SkCanvas::Lattice::kSkip_Flags == fFlags[i]) {
+                fNumRectsToDraw--;
+            }
+        }
+    }
 }
 
 bool SkLatticeIter::Valid(int width, int height, const SkIRect& center) {
     return !center.isEmpty() && SkIRect::MakeWH(width, height).contains(center);
 }
 
 SkLatticeIter::SkLatticeIter(int w, int h, const SkIRect& c, const SkRect& dst) {
     SkASSERT(SkIRect::MakeWH(w, h).contains(c));
 
     fSrcX.reset(4);
@@ skipping 25 matching lines @@
         fDstX[1] = fDstX[0] + (fDstX[3] - fDstX[0]) * c.fLeft / (w - c.width());
         fDstX[2] = fDstX[1];
     }
 
     if (fDstY[1] > fDstY[2]) {
         fDstY[1] = fDstY[0] + (fDstY[3] - fDstY[0]) * c.fTop / (h - c.height());
         fDstY[2] = fDstY[1];
     }
 
     fCurrX = fCurrY = 0;
-    fDone = false;
-    fNumRects = 9;
+    fNumRectsInLattice = 9;
+    fNumRectsToDraw = 9;
 }
 
 bool SkLatticeIter::next(SkRect* src, SkRect* dst) {
-    if (fDone) {
+    int currRect = fCurrX + fCurrY * (fSrcX.count() - 1);
+    if (currRect == fNumRectsInLattice) {
         return false;
     }
 
     const int x = fCurrX;
     const int y = fCurrY;
     SkASSERT(x >= 0 && x < fSrcX.count() - 1);
     SkASSERT(y >= 0 && y < fSrcY.count() - 1);
 
-    src->set(fSrcX[x], fSrcY[y], fSrcX[x + 1], fSrcY[y + 1]);
-    dst->set(fDstX[x], fDstY[y], fDstX[x + 1], fDstY[y + 1]);
     if (fSrcX.count() - 1 == ++fCurrX) {
         fCurrX = 0;
         fCurrY += 1;
-        if (fCurrY >= fSrcY.count() - 1) {
-            fDone = true;
-        }
     }
+
+    if (fFlags.count() > 0 && SkToBool(SkCanvas::Lattice::kSkip_Flags & fFlags[currRect])) {
+        return this->next(src, dst);
+    }
+
+    src->set(fSrcX[x], fSrcY[y], fSrcX[x + 1], fSrcY[y + 1]);
+    dst->set(fDstX[x], fDstY[y], fDstX[x + 1], fDstY[y + 1]);
     return true;
 }
 
 void SkLatticeIter::mapDstScaleTranslate(const SkMatrix& matrix) {
     SkASSERT(matrix.isScaleTranslate());
     SkScalar tx = matrix.getTranslateX();
     SkScalar sx = matrix.getScaleX();
     for (int i = 0; i < fDstX.count(); i++) {
         fDstX[i] = fDstX[i] * sx + tx;
     }
 
     SkScalar ty = matrix.getTranslateY();
     SkScalar sy = matrix.getScaleY();
     for (int i = 0; i < fDstY.count(); i++) {
         fDstY[i] = fDstY[i] * sy + ty;
     }
 }