use integer math instead of float per-pixel. about a 2x speedup. not tested well, so this is just e…

gm/filterbitmap.cpp

Index: gm/filterbitmap.cpp
diff --git a/gm/filterbitmap.cpp b/gm/filterbitmap.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..efb3d1077ad884f3f4c6837b4b20ce2d61edbbd9
--- /dev/null
+++ b/gm/filterbitmap.cpp
@@ -0,0 +1,114 @@
+/*
+ * 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 "SkGradientShader.h"
+
+#include "SkTypeface.h"
+#include "SkImageDecoder.h"
+static void load_bm(SkBitmap* bm) {
+//    SkImageDecoder::DecodeFile("/skia/trunk/books.jpg", bm);
+
+    bm->setConfig(SkBitmap::kARGB_8888_Config, 160, 120);
+    bm->allocPixels();
+    SkCanvas canvas(*bm);
+    canvas.drawColor(SK_ColorWHITE);
+
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    paint.setSubpixelText(true);
+    paint.setTextSize(17);
+
+    paint.setTypeface(SkTypeface::CreateFromName("Times", SkTypeface::kNormal))->unref();
+    canvas.drawText("Hamburgefons", 12, 10, 25, paint);
+    paint.setTypeface(SkTypeface::CreateFromName("Times", SkTypeface::kItalic))->unref();
+    canvas.drawText("Hamburgefons", 12, 10, 50, paint);
+    paint.setTypeface(SkTypeface::CreateFromName("Times", SkTypeface::kBold))->unref();
+    canvas.drawText("Hamburgefons", 12, 10, 75, paint);
+    paint.setTypeface(SkTypeface::CreateFromName("Times", SkTypeface::kBoldItalic))->unref();
+    canvas.drawText("Hamburgefons", 12, 10, 100, paint);
+}
+
+static SkSize computeSize(const SkBitmap& bm, const SkMatrix& mat) {
+    SkRect bounds = { 0, 0, bm.width(), bm.height() };
+    mat.mapRect(&bounds);
+    return SkSize::Make(bounds.width(), bounds.height());
+}
+
+static void draw_col(SkCanvas* canvas, const SkBitmap& bm, const SkMatrix& mat,
+                     SkScalar dx) {
+    SkPaint paint;
+
+    SkAutoCanvasRestore acr(canvas, true);
+
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+
+    paint.setFilterBitmap(true);
+    canvas->translate(dx, 0);
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+
+    paint.setFlags(paint.getFlags() | SkPaint::kBicubicFilterBitmap_Flag);
+    canvas->translate(dx, 0);
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+}
+
+class FilterBitmapGM : public skiagm::GM {
+    bool fOnce;
+    void init() {
+        if (fOnce) {
+            return;
+        }
+        fOnce = true;
+        load_bm(&fBM);
+
+        SkScalar cx = SkScalarHalf(fBM.width());
+        SkScalar cy = SkScalarHalf(fBM.height());
+        SkScalar scale = 1.6f;
+
+        fMatrix[0].setScale(scale, scale);
+        fMatrix[1].setRotate(30, cx, cy); fMatrix[1].postScale(scale, scale);
+    }
+
+public:
+    SkBitmap    fBM;
+    SkMatrix    fMatrix[2];
+
+    FilterBitmapGM() : fOnce(false) {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("filterbitmap");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(920, 480);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        this->init();
+
+        canvas->translate(10, 10);
+        for (size_t i = 0; i < SK_ARRAY_COUNT(fMatrix); ++i) {
+            SkSize size = computeSize(fBM, fMatrix[i]);
+            size.fWidth += 20;
+            size.fHeight += 20;
+
+            draw_col(canvas, fBM, fMatrix[i], size.fWidth);
+            canvas->translate(0, size.fHeight);
+        }
+    }
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return new FilterBitmapGM; )
+