Add drawImageLattice() and drawBitmapLattice() APIs
The specified image/bitmap is divided into rects, which
can be draw stretched, shrunk, or at a fixed size. Will be
used by Android to draw 9patch (which are acutally N-patch)
images.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1992283002
Review-Url: https://codereview.chromium.org/1992283002
diff --git a/src/core/SkLatticeIter.cpp b/src/core/SkLatticeIter.cpp
new file mode 100644
index 0000000..24ab3f1
--- /dev/null
+++ b/src/core/SkLatticeIter.cpp
@@ -0,0 +1,230 @@
+/*
+ * 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"
+
+/**
+ * Divs must be in increasing order with no duplicates.
+ */
+static bool valid_divs(const int* divs, int count, int len) {
+ if (count <= 0) {
+ return false;
+ }
+
+ int prev = -1;
+ for (int i = 0; i < count; i++) {
+ if (prev >= divs[i] || divs[i] > len) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+bool SkLatticeIter::Valid(int width, int height, const SkCanvas::Lattice& lattice) {
+ return valid_divs(lattice.fXDivs, lattice.fXCount, width) &&
+ valid_divs(lattice.fYDivs, lattice.fYCount, height);
+}
+
+/**
+ * Count the number of pixels that are in "scalable" patches.
+ */
+static int count_scalable_pixels(const int32_t* divs, int numDivs, bool firstIsScalable,
+ int length) {
+ if (0 == numDivs) {
+ return firstIsScalable ? length : 0;
+ }
+
+ int i;
+ int count;
+ if (firstIsScalable) {
+ count = divs[0];
+ i = 1;
+ } else {
+ count = 0;
+ i = 0;
+ }
+
+ for (; i < numDivs; i += 2) {
+ // Alternatively, we could use |top| and |bottom| as variable names, instead of
+ // |left| and |right|.
+ int left = divs[i];
+ int right = (i + 1 < numDivs) ? divs[i + 1] : length;
+ count += right - left;
+ }
+
+ return count;
+}
+
+/**
+ * Set points for the src and dst rects on subsequent draw calls.
+ */
+static void set_points(float* dst, float* src, const int* divs, int divCount, int srcFixed,
+ int srcScalable, float dstStart, float dstStop, bool isScalable) {
+
+ float dstLen = dstStop - dstStart;
+ int srcLen = srcFixed + srcScalable;
+ float scale;
+ if (srcFixed <= dstLen) {
+ // This is the "normal" case, where we scale the "scalable" patches and leave
+ // the other patches fixed.
+ scale = (dstLen - ((float) srcFixed)) / ((float) srcScalable);
+ } else {
+ // In this case, we eliminate the "scalable" patches and scale the "fixed" patches.
+ scale = dstLen / ((float) srcFixed);
+ }
+
+ src[0] = 0.0f;
+ dst[0] = dstStart;
+ for (int i = 0; i < divCount; i++) {
+ src[i + 1] = (float) (divs[i]);
+ float srcDelta = src[i + 1] - src[i];
+ float dstDelta;
+ if (srcFixed <= dstLen) {
+ dstDelta = isScalable ? scale * srcDelta : srcDelta;
+ } else {
+ dstDelta = isScalable ? 0.0f : scale * srcDelta;
+ }
+ dst[i + 1] = dst[i] + dstDelta;
+
+ // Alternate between "scalable" and "fixed" patches.
+ isScalable = !isScalable;
+ }
+
+ src[divCount + 1] = (float) srcLen;
+ dst[divCount + 1] = dstStop;
+}
+
+SkLatticeIter::SkLatticeIter(int srcWidth, int srcHeight, const SkCanvas::Lattice& lattice,
+ const SkRect& dst)
+{
+ const int* xDivs = lattice.fXDivs;
+ int xCount = lattice.fXCount;
+ const int* yDivs = lattice.fYDivs;
+ int yCount = lattice.fYCount;
+
+ // In the x-dimension, the first rectangle always starts at x = 0 and is "scalable".
+ // If xDiv[0] is 0, it indicates that the first rectangle is degenerate, so the
+ // first real rectangle "scalable" in the x-direction.
+ //
+ // The same interpretation applies to the y-dimension.
+ //
+ // As we move left to right across the image, alternating patches will be "fixed" or
+ // "scalable" in the x-direction. Similarly, as move top to bottom, alternating
+ // patches will be "fixed" or "scalable" in the y-direction.
+ SkASSERT(xCount > 0 && yCount > 0);
+ bool xIsScalable = (0 == xDivs[0]);
+ if (xIsScalable) {
+ // Once we've decided that the first patch is "scalable", we don't need the
+ // xDiv. It is always implied that we start at zero.
+ xDivs++;
+ xCount--;
+ }
+ bool yIsScalable = (0 == yDivs[0]);
+ if (yIsScalable) {
+ // Once we've decided that the first patch is "scalable", we don't need the
+ // yDiv. It is always implied that we start at zero.
+ yDivs++;
+ yCount--;
+ }
+
+ // We never need the final xDiv/yDiv if it is equal to the width/height. This is implied.
+ if (xCount > 0 && srcWidth == xDivs[xCount - 1]) {
+ xCount--;
+ }
+ if (yCount > 0 && srcHeight == yDivs[yCount - 1]) {
+ yCount--;
+ }
+
+ // Count "scalable" and "fixed" pixels in each dimension.
+ int xCountScalable = count_scalable_pixels(xDivs, xCount, xIsScalable, srcWidth);
+ int xCountFixed = srcWidth - xCountScalable;
+ int yCountScalable = count_scalable_pixels(yDivs, yCount, yIsScalable, srcHeight);
+ int yCountFixed = srcHeight - yCountScalable;
+
+ fSrcX.reset(xCount + 2);
+ 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;
+}
+
+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);
+ fSrcY.reset(4);
+ fDstX.reset(4);
+ fDstY.reset(4);
+
+ fSrcX[0] = 0;
+ fSrcX[1] = SkIntToScalar(c.fLeft);
+ fSrcX[2] = SkIntToScalar(c.fRight);
+ fSrcX[3] = SkIntToScalar(w);
+
+ fSrcY[0] = 0;
+ fSrcY[1] = SkIntToScalar(c.fTop);
+ fSrcY[2] = SkIntToScalar(c.fBottom);
+ fSrcY[3] = SkIntToScalar(h);
+
+ fDstX[0] = dst.fLeft;
+ fDstX[1] = dst.fLeft + SkIntToScalar(c.fLeft);
+ fDstX[2] = dst.fRight - SkIntToScalar(w - c.fRight);
+ fDstX[3] = dst.fRight;
+
+ fDstY[0] = dst.fTop;
+ fDstY[1] = dst.fTop + SkIntToScalar(c.fTop);
+ fDstY[2] = dst.fBottom - SkIntToScalar(h - c.fBottom);
+ fDstY[3] = dst.fBottom;
+
+ if (fDstX[1] > fDstX[2]) {
+ 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;
+}
+
+bool SkLatticeIter::next(SkRect* src, SkRect* dst) {
+ if (fDone) {
+ 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;
+ }
+ }
+ return true;
+}