Add option to skip rects to drawImageLattice()

src/core/SkLatticeIter.cpp

Index: src/core/SkLatticeIter.cpp
diff --git a/src/core/SkLatticeIter.cpp b/src/core/SkLatticeIter.cpp
index ba6ac97a5b4395807a22c482b05e95ccc985eb0c..91f9ae960fc56c718fb6837fc7d72384a14988d7 100644
--- a/src/core/SkLatticeIter.cpp
+++ b/src/core/SkLatticeIter.cpp
@@ -158,8 +158,18 @@ SkLatticeIter::SkLatticeIter(int srcWidth, int srcHeight, const SkCanvas::Lattic
                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) {
@@ -205,12 +215,13 @@ SkLatticeIter::SkLatticeIter(int w, int h, const SkIRect& c, const SkRect& dst)
     }
 
     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;
     }
 
@@ -219,15 +230,17 @@ bool SkLatticeIter::next(SkRect* src, SkRect* dst) {
     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;
 }