Add drawBitmapLattice() API

gm/lattice.cpp

Index: gm/lattice.cpp
diff --git a/gm/lattice.cpp b/gm/lattice.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..63de2a66b407d6d2d2adbf6d549a24d06d1930ea
--- /dev/null
+++ b/gm/lattice.cpp
@@ -0,0 +1,147 @@
+/*
+ * 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"
+
+static sk_sp<SkSurface> make_surface(SkCanvas* root, int N) {
+    SkImageInfo info = SkImageInfo::MakeN32Premul(N, N);
+    auto surface = root->makeSurface(info);
+    if (!surface) {
+        surface = SkSurface::MakeRaster(info);
+    }
+    return surface;
+}
+
+static sk_sp<SkImage> make_image(SkCanvas* root, int* xDivs, int* yDivs) {
+    const int kCap = 28;
+    const int kMid = 8;
+    const int kSize = 2*kCap + 3*kMid;
+
+    auto surface(make_surface(root, kSize));
+    SkCanvas* canvas = surface->getCanvas();
+
+    SkRect r = SkRect::MakeWH(SkIntToScalar(kSize), SkIntToScalar(kSize));
+    const SkScalar strokeWidth = SkIntToScalar(6);
+    const SkScalar radius = SkIntToScalar(kCap) - strokeWidth/2;
+
+    xDivs[0] = yDivs[0] = kCap;
+    xDivs[1] = yDivs[1] = kCap + kMid;
+    xDivs[2] = yDivs[2] = kCap + 2 * kMid;
+    xDivs[3] = yDivs[3] = kCap + 3 * kMid;
+
+    SkPaint paint;
+    paint.setAntiAlias(true);
+
+    paint.setColor(0xFFFFFF00);
+    canvas->drawRoundRect(r, radius, radius, paint);
+
+    r.setXYWH(SkIntToScalar(kCap), 0, SkIntToScalar(kMid), SkIntToScalar(kSize));
+    paint.setColor(0x8800FF00);
+    canvas->drawRect(r, paint);
+    r.setXYWH(SkIntToScalar(kCap + kMid), 0, SkIntToScalar(kMid), SkIntToScalar(kSize));
+    paint.setColor(0x880000FF);
+    canvas->drawRect(r, paint);
+    r.setXYWH(SkIntToScalar(kCap + 2*kMid), 0, SkIntToScalar(kMid), SkIntToScalar(kSize));
+    paint.setColor(0x88FF00FF);
+    canvas->drawRect(r, paint);
+
+    r.setXYWH(0, SkIntToScalar(kCap), SkIntToScalar(kSize), SkIntToScalar(kMid));
+    paint.setColor(0x8800FF00);
+    canvas->drawRect(r, paint);
+    r.setXYWH(0, SkIntToScalar(kCap + kMid), SkIntToScalar(kSize), SkIntToScalar(kMid));
+    paint.setColor(0x880000FF);
+    canvas->drawRect(r, paint);
+    r.setXYWH(0, SkIntToScalar(kCap + 2*kMid), SkIntToScalar(kSize), SkIntToScalar(kMid));
+    paint.setColor(0x88FF00FF);
+    canvas->drawRect(r, paint);
+
+    return surface->makeImageSnapshot();
+}
+
+static void image_to_bitmap(const SkImage* image, SkBitmap* bm) {
+    SkImageInfo info = SkImageInfo::MakeN32Premul(image->width(), image->height());
+    bm->allocPixels(info);
+    image->readPixels(info, bm->getPixels(), bm->rowBytes(), 0, 0);
+}
+
+/**
+ *  This is similar to NinePatchStretchGM, but it also tests "ninepatch" images with more
+ *  than nine patches.
+ */
+class LatticeGM : public skiagm::GM {
+public:
+    LatticeGM() {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("lattice");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(800, 400);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        int xDivs[5];
+        int yDivs[5];
+        xDivs[0] = 0;
+        yDivs[0] = 0;
+
+        SkBitmap bitmap;
+        sk_sp<SkImage> image = make_image(canvas, xDivs + 1, yDivs + 1);
+        image_to_bitmap(image.get(), &bitmap);
+
+        const SkTSize<SkScalar> size[] = {
+            {  50,  50, }, // shrink in both axes
+            {  50, 200, }, // shrink in X
+            { 200,  50, }, // shrink in Y
+            { 200, 200, },
+        };
+
+        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;
+
+        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;
+
+        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; )