skia2/gm/anisotropic.cpp
robertphillips f5ac972207 Add GM to exercise high quality anisotropic scaling
High quality anisotropic is an interesting edge case for the gpu backend. For scales that are both minimizing and maximizing Ganesh falls back to MipMaps which can turn out too blurry.

BUG=472864

Review URL: https://codereview.chromium.org/1058133003
2015-04-14 08:19:01 -07:00

115 lines
3.6 KiB
C++

/*
* Copyright 2015 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"
namespace skiagm {
// This GM exercises HighQuality anisotropic filtering.
class AnisotropicGM : public GM {
public:
AnisotropicGM() : fFilterQuality(kHigh_SkFilterQuality) {
this->setBGColor(0xFFCCCCCC);
}
protected:
SkString onShortName() override { return SkString("anisotropic_hq"); }
SkISize onISize() override {
return SkISize::Make(2*kImageSize + 3*kSpacer,
kNumVertImages*kImageSize + (kNumVertImages+1)*kSpacer);
}
// Create an image consisting of lines radiating from its center
void onOnceBeforeDraw() override {
static const int kNumLines = 100;
static const SkScalar kAngleStep = 360.0f / kNumLines;
static const int kInnerOffset = 10;
fBM.allocN32Pixels(kImageSize, kImageSize, true);
SkCanvas canvas(fBM);
canvas.clear(SK_ColorWHITE);
SkPaint p;
p.setAntiAlias(true);
SkScalar angle = 0.0f, sin, cos;
canvas.translate(kImageSize/2.0f, kImageSize/2.0f);
for (int i = 0; i < kNumLines; ++i, angle += kAngleStep) {
sin = SkScalarSinCos(angle, &cos);
canvas.drawLine(cos * kInnerOffset, sin * kInnerOffset,
cos * kImageSize/2, sin * kImageSize/2, p);
}
}
void draw(SkCanvas* canvas, int x, int y, int xSize, int ySize) {
SkRect r = SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
SkIntToScalar(xSize), SkIntToScalar(ySize));
SkPaint p;
p.setFilterQuality(fFilterQuality);
canvas->drawBitmapRect(fBM, r, &p);
}
void onDraw(SkCanvas* canvas) override {
SkScalar gScales[] = { 0.9f, 0.8f, 0.75f, 0.6f, 0.5f, 0.4f, 0.25f, 0.2f, 0.1f };
SkASSERT(kNumVertImages-1 == (int)SK_ARRAY_COUNT(gScales)/2);
// Minimize vertically
for (int i = 0; i < (int)SK_ARRAY_COUNT(gScales); ++i) {
int height = SkScalarFloorToInt(fBM.height() * gScales[i]);
int yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
yOff = kSpacer + i * (fBM.height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
yOff = (SK_ARRAY_COUNT(gScales) - i) * (fBM.height() + kSpacer) - height;
}
this->draw(canvas, kSpacer, yOff, fBM.width(), height);
}
// Minimize horizontally
for (int i = 0; i < (int)SK_ARRAY_COUNT(gScales); ++i) {
int width = SkScalarFloorToInt(fBM.width() * gScales[i]);
int xOff, yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
xOff = fBM.width() + 2*kSpacer;
yOff = kSpacer + i * (fBM.height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
xOff = fBM.width() + 2*kSpacer + fBM.width() - width;
yOff = kSpacer + (SK_ARRAY_COUNT(gScales) - i - 1) * (fBM.height() + kSpacer);
}
this->draw(canvas, xOff, yOff, width, fBM.height());
}
}
private:
static const int kImageSize = 256;
static const int kSpacer = 10;
static const int kNumVertImages = 5;
SkBitmap fBM;
SkFilterQuality fFilterQuality;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM( return SkNEW(AnisotropicGM); )
}