Add per-vertex coverage field, use in AA rects when alpha tweak is not valid, add relevant sample/gm
Review URL: http://codereview.appspot.com/5181044/
git-svn-id: http://skia.googlecode.com/svn/trunk@2440 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/aarectmodes.cpp b/gm/aarectmodes.cpp
new file mode 100644
index 0000000..ffb267d
--- /dev/null
+++ b/gm/aarectmodes.cpp
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2011 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 "SkCanvas.h"
+#include "SkColorPriv.h"
+#include "SkShader.h"
+
+static SkCanvas* create_canvas(int w, int h) {
+ SkBitmap bm;
+ bm.setConfig(SkBitmap::kARGB_8888_Config, w, h);
+ bm.allocPixels();
+ bm.eraseColor(0);
+ return new SkCanvas(bm);
+}
+
+static const SkBitmap& extract_bitmap(SkCanvas* canvas) {
+ return canvas->getDevice()->accessBitmap(false);
+}
+
+static const struct {
+ SkXfermode::Mode fMode;
+ const char* fLabel;
+} gModes[] = {
+ { SkXfermode::kClear_Mode, "Clear" },
+ { SkXfermode::kSrc_Mode, "Src" },
+ { SkXfermode::kDst_Mode, "Dst" },
+ { SkXfermode::kSrcOver_Mode, "SrcOver" },
+ { SkXfermode::kDstOver_Mode, "DstOver" },
+ { SkXfermode::kSrcIn_Mode, "SrcIn" },
+ { SkXfermode::kDstIn_Mode, "DstIn" },
+ { SkXfermode::kSrcOut_Mode, "SrcOut" },
+ { SkXfermode::kDstOut_Mode, "DstOut" },
+ { SkXfermode::kSrcATop_Mode, "SrcATop" },
+ { SkXfermode::kDstATop_Mode, "DstATop" },
+ { SkXfermode::kXor_Mode, "Xor" },
+};
+
+const int gWidth = 64;
+const int gHeight = 64;
+const SkScalar W = SkIntToScalar(gWidth);
+const SkScalar H = SkIntToScalar(gHeight);
+
+static SkScalar drawCell(SkCanvas* canvas, SkXfermode* mode,
+ SkAlpha a0, SkAlpha a1) {
+
+ SkPaint paint;
+ paint.setAntiAlias(true);
+
+ SkRect r = SkRect::MakeWH(W, H);
+ r.inset(W/10, H/10);
+
+ paint.setColor(SK_ColorBLUE);
+ paint.setAlpha(a0);
+ canvas->drawOval(r, paint);
+
+ paint.setColor(SK_ColorRED);
+ paint.setAlpha(a1);
+ paint.setXfermode(mode);
+
+ SkScalar offset = SK_Scalar1 / 3;
+ SkRect rect = SkRect::MakeXYWH(W / 4 + offset,
+ H / 4 + offset,
+ W / 2, H / 2);
+ canvas->drawRect(rect, paint);
+
+ return H;
+}
+
+static SkShader* make_bg_shader() {
+ SkBitmap bm;
+ bm.setConfig(SkBitmap::kARGB_8888_Config, 2, 2);
+ bm.allocPixels();
+ *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
+ *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = SkPackARGB32(0xFF, 0xCC,
+ 0xCC, 0xCC);
+
+ SkShader* s = SkShader::CreateBitmapShader(bm,
+ SkShader::kRepeat_TileMode,
+ SkShader::kRepeat_TileMode);
+
+ SkMatrix m;
+ m.setScale(SkIntToScalar(6), SkIntToScalar(6));
+ s->setLocalMatrix(m);
+ return s;
+}
+
+namespace skiagm {
+
+ class AARectModesGM : public GM {
+ SkPaint fBGPaint;
+ public:
+ AARectModesGM () {
+ fBGPaint.setShader(make_bg_shader())->unref();
+ }
+
+ protected:
+
+ virtual SkString onShortName() {
+ return SkString("aarectmodes");
+ }
+
+ virtual SkISize onISize() { return make_isize(640, 480); }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ canvas->drawColor(SK_ColorWHITE);
+
+ const SkRect bounds = SkRect::MakeWH(W, H);
+ static const SkAlpha gAlphaValue[] = { 0xFF, 0x88, 0x88 };
+
+ canvas->translate(SkIntToScalar(4), SkIntToScalar(4));
+
+ for (int alpha = 0; alpha < 4; ++alpha) {
+ canvas->save();
+ canvas->save();
+ for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); ++i) {
+ if (6 == i) {
+ canvas->restore();
+ canvas->translate(W * 5, 0);
+ canvas->save();
+ }
+ SkXfermode* mode = SkXfermode::Create(gModes[i].fMode);
+
+ canvas->drawRect(bounds, fBGPaint);
+ canvas->saveLayer(&bounds, NULL);
+ SkScalar dy = drawCell(canvas, mode,
+ gAlphaValue[alpha & 1],
+ gAlphaValue[alpha & 2]);
+ canvas->restore();
+
+ canvas->translate(0, dy * 5 / 4);
+ SkSafeUnref(mode);
+ }
+ canvas->restore();
+ canvas->restore();
+ canvas->translate(W * 5 / 4, 0);
+ }
+ }
+
+ // disable pdf for now, since it crashes on mac
+ virtual uint32_t onGetFlags() const { return kSkipPDF_Flag; }
+
+ private:
+ typedef GM INHERITED;
+ };
+
+//////////////////////////////////////////////////////////////////////////////
+
+ static GM* MyFactory(void*) { return new AARectModesGM; }
+ static GMRegistry reg(MyFactory);
+
+}
+