use higher precision (64bit) fixed-point for matrix proc

Review URL: https://codereview.appspot.com/5772044

git-svn-id: http://skia.googlecode.com/svn/trunk@3336 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 103 insertions, 0 deletions

diff --git a/gm/giantbitmap.cpp b/gm/giantbitmap.cpp
new file mode 100644
index 0000000000..30f3af1e9e
--- /dev/null
+++ b/gm/giantbitmap.cpp
@@ -0,0 +1,103 @@
+/*
+ * 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"
+
+/*
+ *  Want to ensure that our bitmap sampler (in bitmap shader) keeps plenty of
+ *  precision when scaling very large images (where the dx might get very small.
+ */
+
+#define W   2560
+#define H   1600
+
+class GiantBitmapGM : public skiagm::GM {
+    SkBitmap* fBM;
+    SkShader::TileMode fMode;
+    
+    const SkBitmap& getBitmap() {
+        if (NULL == fBM) {
+            fBM = new SkBitmap;
+            fBM->setConfig(SkBitmap::kARGB_8888_Config, W, H);
+            fBM->allocPixels();
+            fBM->eraseColor(SK_ColorWHITE);
+
+            const SkColor colors[] = {
+                SK_ColorBLUE, SK_ColorRED, SK_ColorBLACK, SK_ColorGREEN
+            };
+
+            SkCanvas canvas(*fBM);
+            SkPaint paint;
+            paint.setAntiAlias(true);
+            paint.setStrokeWidth(SkIntToScalar(30));
+            for (int y = -H; y < H; y += 80) {
+                SkScalar yy = SkIntToScalar(y);
+                paint.setColor(colors[y/80 & 0x3]);
+                canvas.drawLine(0, yy, SkIntToScalar(W), yy + SkIntToScalar(W),
+                                paint);
+            }
+        }
+        return *fBM;
+    }
+
+public:
+    GiantBitmapGM(SkShader::TileMode mode) : fBM(NULL), fMode(mode) {}
+
+    virtual ~GiantBitmapGM() {
+        SkDELETE(fBM);
+    }
+
+protected:
+
+    virtual SkString onShortName() {
+        SkString str("giantbitmap_");
+        switch (fMode) {
+            case SkShader::kClamp_TileMode:
+                str.append("clamp");
+                break;
+            case SkShader::kRepeat_TileMode:
+                str.append("repeat");
+                break;
+            case SkShader::kMirror_TileMode:
+                str.append("mirror");
+                break;
+            default:
+                break;
+        }
+        return str;
+    }
+
+    virtual SkISize onISize() { return SkISize::Make(640, 480); }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        SkPaint paint;
+        SkShader* s = SkShader::CreateBitmapShader(getBitmap(), fMode, fMode);
+        SkMatrix m;
+        m.setScale(2*SK_Scalar1/3, 2*SK_Scalar1/3);
+        s->setLocalMatrix(m);
+        paint.setShader(s)->unref();
+
+        canvas->drawPaint(paint);
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static skiagm::GM* G0(void*) { return new GiantBitmapGM(SkShader::kClamp_TileMode); }
+static skiagm::GM* G1(void*) { return new GiantBitmapGM(SkShader::kRepeat_TileMode); }
+static skiagm::GM* G2(void*) { return new GiantBitmapGM(SkShader::kMirror_TileMode); }
+
+static skiagm::GMRegistry reg0(G0);
+static skiagm::GMRegistry reg1(G1);
+static skiagm::GMRegistry reg2(G2);
+