Implement SkXfermode image filter. This required changing the signature of SkXfermode::asNewEffectOrCoeffs(), to add an optional background texture.
For the raster path, we do a straightforward 2-pass method: draw background, then composite the foreground over it.
For the GPU path, if the xfermode can be expressed as an effect, we build an effect with the background texture incorporated, then do a single-pass draw fetching both foreground and background textures, and compositing to the result. If the xfermode is expressed as src/dst coefficients, we do a 2-pass draw as in the raster path and use fixed-function blending.
R=bsalomon@google.com, reed@google.com
Review URL: https://codereview.chromium.org/16125008
git-svn-id: http://skia.googlecode.com/svn/trunk@9373 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/xfermodeimagefilter.cpp b/gm/xfermodeimagefilter.cpp
new file mode 100644
index 0000000..a6d395e
--- /dev/null
+++ b/gm/xfermodeimagefilter.cpp
@@ -0,0 +1,163 @@
+/*
+ * Copyright 2013 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 "SkArithmeticMode.h"
+#include "SkXfermodeImageFilter.h"
+#include "SkBitmapSource.h"
+
+#define WIDTH 600
+#define HEIGHT 600
+#define MARGIN 12
+
+namespace skiagm {
+
+class XfermodeImageFilterGM : public GM {
+public:
+ XfermodeImageFilterGM() : fInitialized(false) {
+ this->setBGColor(0xFF000000);
+ }
+
+protected:
+ virtual SkString onShortName() {
+ return SkString("xfermodeimagefilter");
+ }
+
+ void make_bitmap() {
+ fBitmap.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+ fBitmap.allocPixels();
+ SkDevice device(fBitmap);
+ SkCanvas canvas(&device);
+ canvas.clear(0x00000000);
+ SkPaint paint;
+ paint.setAntiAlias(true);
+ paint.setColor(0xD000D000);
+ paint.setTextSize(SkIntToScalar(96));
+ const char* str = "e";
+ canvas.drawText(str, strlen(str), SkIntToScalar(15), SkIntToScalar(65), paint);
+ }
+
+ void make_checkerboard() {
+ fCheckerboard.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+ fCheckerboard.allocPixels();
+ SkDevice device(fCheckerboard);
+ SkCanvas canvas(&device);
+ canvas.clear(0x00000000);
+ SkPaint darkPaint;
+ darkPaint.setColor(0xFF404040);
+ SkPaint lightPaint;
+ lightPaint.setColor(0xFFA0A0A0);
+ for (int y = 0; y < 80; y += 16) {
+ for (int x = 0; x < 80; x += 16) {
+ canvas.save();
+ canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
+ canvas.drawRect(SkRect::MakeXYWH(0, 0, 8, 8), darkPaint);
+ canvas.drawRect(SkRect::MakeXYWH(8, 0, 8, 8), lightPaint);
+ canvas.drawRect(SkRect::MakeXYWH(0, 8, 8, 8), lightPaint);
+ canvas.drawRect(SkRect::MakeXYWH(8, 8, 8, 8), darkPaint);
+ canvas.restore();
+ }
+ }
+ }
+
+ virtual SkISize onISize() {
+ return make_isize(WIDTH, HEIGHT);
+ }
+
+ void drawClippedBitmap(SkCanvas* canvas, const SkBitmap& bitmap, const SkPaint& paint, SkScalar x, SkScalar y) {
+ canvas->save();
+ canvas->clipRect(SkRect::MakeXYWH(x, y,
+ SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height())));
+ canvas->drawBitmap(bitmap, x, y, &paint);
+ canvas->restore();
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ if (!fInitialized) {
+ make_bitmap();
+ make_checkerboard();
+ fInitialized = true;
+ }
+ canvas->clear(0x00000000);
+ SkPaint paint;
+
+ 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" },
+
+ { SkXfermode::kPlus_Mode, "Plus" },
+ { SkXfermode::kModulate_Mode, "Modulate" },
+ { SkXfermode::kScreen_Mode, "Screen" },
+ { SkXfermode::kOverlay_Mode, "Overlay" },
+ { SkXfermode::kDarken_Mode, "Darken" },
+ { SkXfermode::kLighten_Mode, "Lighten" },
+ { SkXfermode::kColorDodge_Mode, "ColorDodge" },
+ { SkXfermode::kColorBurn_Mode, "ColorBurn" },
+ { SkXfermode::kHardLight_Mode, "HardLight" },
+ { SkXfermode::kSoftLight_Mode, "SoftLight" },
+ { SkXfermode::kDifference_Mode, "Difference" },
+ { SkXfermode::kExclusion_Mode, "Exclusion" },
+ { SkXfermode::kMultiply_Mode, "Multiply" },
+ { SkXfermode::kHue_Mode, "Hue" },
+ { SkXfermode::kSaturation_Mode, "Saturation" },
+ { SkXfermode::kColor_Mode, "Color" },
+ { SkXfermode::kLuminosity_Mode, "Luminosity" },
+ };
+
+ int x = 0, y = 0;
+ SkAutoTUnref<SkImageFilter> background(SkNEW_ARGS(SkBitmapSource, (fCheckerboard)));
+ for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); i++) {
+ SkAutoTUnref<SkXfermode> mode(SkXfermode::Create(gModes[i].fMode));
+ SkAutoTUnref<SkImageFilter> filter(SkNEW_ARGS(SkXfermodeImageFilter, (mode, background)));
+ paint.setImageFilter(filter);
+ drawClippedBitmap(canvas, fBitmap, paint, SkIntToScalar(x), SkIntToScalar(y));
+ x += fBitmap.width() + MARGIN;
+ if (x + fBitmap.width() > WIDTH) {
+ x = 0;
+ y += fBitmap.height() + MARGIN;
+ }
+ }
+ // Test arithmetic mode as image filter
+ SkAutoTUnref<SkXfermode> mode(SkArithmeticMode::Create(0, SK_Scalar1, SK_Scalar1, 0));
+ SkAutoTUnref<SkImageFilter> filter(SkNEW_ARGS(SkXfermodeImageFilter, (mode, background)));
+ paint.setImageFilter(filter);
+ drawClippedBitmap(canvas, fBitmap, paint, SkIntToScalar(x), SkIntToScalar(y));
+ x += fBitmap.width() + MARGIN;
+ if (x + fBitmap.width() > WIDTH) {
+ x = 0;
+ y += fBitmap.height() + MARGIN;
+ }
+ // Test NULL mode
+ filter.reset(SkNEW_ARGS(SkXfermodeImageFilter, (NULL, background)));
+ paint.setImageFilter(filter);
+ drawClippedBitmap(canvas, fBitmap, paint, SkIntToScalar(x), SkIntToScalar(y));
+ }
+private:
+ typedef GM INHERITED;
+ SkBitmap fBitmap, fCheckerboard;
+ bool fInitialized;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new XfermodeImageFilterGM; }
+static GMRegistry reg(MyFactory);
+
+}