add first cut at arithmetic mode
git-svn-id: http://skia.googlecode.com/svn/trunk@2849 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/arithmode.cpp b/gm/arithmode.cpp
new file mode 100644
index 0000000..4a7bef2
--- /dev/null
+++ b/gm/arithmode.cpp
@@ -0,0 +1,139 @@
+/*
+ * 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"
+
+#include "SkArithmeticMode.h"
+#include "SkGradientShader.h"
+#define WW 100
+#define HH 32
+
+static SkBitmap make_bm() {
+ SkBitmap bm;
+ bm.setConfig(SkBitmap::kARGB_8888_Config, WW, HH);
+ bm.allocPixels();
+ bm.eraseColor(0);
+ return bm;
+}
+
+static SkBitmap make_src() {
+ SkBitmap bm = make_bm();
+ SkCanvas canvas(bm);
+ SkPaint paint;
+ SkPoint pts[] = { 0, 0, WW, HH };
+ SkColor colors[] = {
+ SK_ColorBLACK, SK_ColorGREEN, SK_ColorCYAN,
+ SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE
+ };
+ SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
+ SkShader::kClamp_TileMode);
+ paint.setShader(s)->unref();
+ canvas.drawPaint(paint);
+ return bm;
+}
+
+static SkBitmap make_dst() {
+ SkBitmap bm = make_bm();
+ SkCanvas canvas(bm);
+ SkPaint paint;
+ SkPoint pts[] = { 0, HH, WW, 0 };
+ SkColor colors[] = {
+ SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN, SK_ColorGRAY
+ };
+ SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
+ SkShader::kClamp_TileMode);
+ paint.setShader(s)->unref();
+ canvas.drawPaint(paint);
+ return bm;
+}
+
+static SkBitmap make_arith(const SkBitmap& src, const SkBitmap& dst,
+ const SkScalar k[]) {
+ SkBitmap bm = make_bm();
+ SkCanvas canvas(bm);
+ SkPaint paint;
+ canvas.drawBitmap(dst, 0, 0, NULL);
+ SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]);
+ paint.setXfermode(xfer)->unref();
+ canvas.drawBitmap(src, 0, 0, &paint);
+ return bm;
+}
+
+static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
+ SkPaint paint;
+ paint.setTextSize(24);
+ paint.setAntiAlias(true);
+ for (int i = 0; i < 4; ++i) {
+ SkString str;
+ str.appendScalar(k[i]);
+ SkScalar width = paint.measureText(str.c_str(), str.size());
+ canvas->drawText(str.c_str(), str.size(), x, y + 24, paint);
+ x += width + 10;
+ }
+}
+
+class ArithmodeGM : public skiagm::GM {
+public:
+ ArithmodeGM () {}
+
+protected:
+
+ virtual SkString onShortName() {
+ return SkString("arithmode");
+ }
+
+ virtual SkISize onISize() { return SkISize::Make(640, 480); }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ SkBitmap src = make_src();
+ SkBitmap dst = make_dst();
+
+ static const SkScalar K[] = {
+ 0, 0, 0, 0,
+ 0, 0, 0, 1,
+ 0, 1, 0, 0,
+ 0, 0, 1, 0,
+ 0, 1, 1, 0,
+ 0, 1, -1, 0,
+ 0, 0.5f, 0.5f, 0,
+ 0, 0.5f, 0.5f, 0.25f,
+ 0, 0.5f, 0.5f, -0.25f,
+ 0.25f, 0.5f, 0.5f, 0,
+ -0.25f, 0.5f, 0.5f, 0,
+ };
+
+ const SkScalar* k = K;
+ const SkScalar* stop = k + SK_ARRAY_COUNT(K);
+ SkScalar y = 0;
+ SkScalar x = 0;
+ SkScalar gap = src.width() + 20;
+ while (k < stop) {
+ SkScalar x = 0;
+ SkBitmap res = make_arith(src, dst, k);
+ canvas->drawBitmap(src, x, y, NULL);
+ x += gap;
+ canvas->drawBitmap(dst, x, y, NULL);
+ x += gap;
+ canvas->drawBitmap(res, x, y, NULL);
+ x += gap;
+ show_k_text(canvas, x, y, k);
+ k += 4;
+ y += src.height() + 12;
+ }
+ }
+
+private:
+ typedef GM INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static skiagm::GM* MyFactory(void*) { return new ArithmodeGM; }
+static skiagm::GMRegistry reg(MyFactory);