add first cut at arithmetic mode

git-svn-id: http://skia.googlecode.com/svn/trunk@2849 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 139 insertions, 0 deletions

diff --git a/gm/arithmode.cpp b/gm/arithmode.cpp
new file mode 100644
index 0000000000..4a7bef269d
--- /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);