Make image scaling have floating point scales. Third attempt to land this

gm/filterindiabox.cpp

+/*
+ * 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"
+#include "SkStream.h"
+
+#include "SkImageEncoder.h"
+#include "SkBitmapScaler.h"
+#include "SkBitmapProcState.h"
+
+static SkSize computeSize(const SkBitmap& bm, const SkMatrix& mat) {
+    SkRect bounds = SkRect::MakeWH(SkIntToScalar(bm.width()),
+                                   SkIntToScalar(bm.height()));
+    mat.mapRect(&bounds);
+    return SkSize::Make(bounds.width(), bounds.height());
+}
+
+static void draw_row(SkCanvas* canvas, const SkBitmap& bm, const SkMatrix& mat, SkScalar dx) {
+    SkPaint paint;
+
+    SkAutoCanvasRestore acr(canvas, true);
+
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+
+    paint.setFilterLevel(SkPaint::kLow_FilterLevel);
+    canvas->translate(dx, 0);
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+
+    paint.setFilterLevel(SkPaint::kMedium_FilterLevel);
+    canvas->translate(dx, 0);
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+
+    paint.setFilterLevel(SkPaint::kHigh_FilterLevel);
+    canvas->translate(dx, 0);
+    canvas->drawBitmapMatrix(bm, mat, &paint);
+}
+
+class FilterIndiaBoxGM : public skiagm::GM {
+    void onOnceBeforeDraw() {
+
+        this->makeBitmap();
+
+        SkScalar cx = SkScalarHalf(fBM.width());
+        SkScalar cy = SkScalarHalf(fBM.height());
+
+        float vertScale = 30.0f/55.0f;
+        float horizScale = 150.0f/200.0f;
+
+        fMatrix[0].setScale(horizScale, vertScale);
+        fMatrix[1].setRotate(30, cx, cy); fMatrix[1].postScale(horizScale, vertScale);
+    }
+
+public:
+    SkBitmap    fBM;
+    SkMatrix    fMatrix[2];
+    SkString    fName;
+
+    FilterIndiaBoxGM()
+    {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+    FilterIndiaBoxGM(const char filename[])
+      : fFilename(filename)
+    {
+        fName.printf("filterindiabox");
+    }
+
+protected:
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return kSkipTiled_Flag;
+    }
+
+    virtual SkString onShortName() SK_OVERRIDE {
+        return fName;
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(1024, 768);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+
+        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_row(canvas, fBM, fMatrix[i], size.fWidth);
+            canvas->translate(0, size.fHeight);
+        }
+    }
+
+  protected:
+      SkString fFilename;
+      int fSize;
+
+      SkScalar getScale() {
+          return 192.f/fSize;
+      }
+
+      void makeBitmap() {
+          SkString path(skiagm::GM::gResourcePath);
+          path.append("/");
+          path.append(fFilename);
+
+          SkImageDecoder *codec = NULL;
+          SkFILEStream stream(path.c_str());
+          if (stream.isValid()) {
+              codec = SkImageDecoder::Factory(&stream);
+          }
+          if (codec) {
+              stream.rewind();
+              codec->decode(&stream, &fBM, SkBitmap::kARGB_8888_Config,
+                  SkImageDecoder::kDecodePixels_Mode);
+              SkDELETE(codec);
+          } else {
+              fBM.allocN32Pixels(1, 1);
+              *(fBM.getAddr32(0,0)) = 0xFF0000FF; // red == bad
+          }
+          fSize = fBM.height();
+      }
+  private:
+    typedef skiagm::GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+
+DEF_GM( return new FilterIndiaBoxGM("box.gif"); )