skia2/gm/anisotropic.cpp
Mike Reed f3ac2afbb6 Name common cubic resamplers
Useful in client code to document what we're doing as we switch away
from SkFilterQuality.

Change-Id: I05737beb99a567a46a3c3ec418b7f7da71b1ff62
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/366723
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
2021-02-05 19:21:04 +00:00

124 lines
4.1 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/gm.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkFilterQuality.h"
#include "include/core/SkImage.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRect.h"
#include "include/core/SkScalar.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkSurface.h"
namespace skiagm {
// This GM exercises HighQuality anisotropic filtering.
class AnisotropicGM : public GM {
public:
AnisotropicGM() : fSampling(SkCubicResampler::Mitchell()) {
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 {
constexpr int kNumLines = 100;
constexpr SkScalar kAngleStep = 360.0f / kNumLines;
constexpr int kInnerOffset = 10;
auto info = SkImageInfo::MakeN32(kImageSize, kImageSize, kOpaque_SkAlphaType);
auto surf = SkSurface::MakeRaster(info);
auto canvas = surf->getCanvas();
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 = SkScalarSin(angle);
cos = SkScalarCos(angle);
canvas->drawLine(cos * kInnerOffset, sin * kInnerOffset,
cos * kImageSize/2, sin * kImageSize/2, p);
}
fImage = surf->makeImageSnapshot();
}
void draw(SkCanvas* canvas, int x, int y, int xSize, int ySize) {
SkRect r = SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
SkIntToScalar(xSize), SkIntToScalar(ySize));
canvas->drawImageRect(fImage, r, fSampling);
}
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(fImage->height() * gScales[i]);
int yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
yOff = kSpacer + i * (fImage->height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
yOff = (SK_ARRAY_COUNT(gScales) - i) * (fImage->height() + kSpacer) - height;
}
this->draw(canvas, kSpacer, yOff, fImage->width(), height);
}
// Minimize horizontally
for (int i = 0; i < (int)SK_ARRAY_COUNT(gScales); ++i) {
int width = SkScalarFloorToInt(fImage->width() * gScales[i]);
int xOff, yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
xOff = fImage->width() + 2*kSpacer;
yOff = kSpacer + i * (fImage->height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
xOff = fImage->width() + 2*kSpacer + fImage->width() - width;
yOff = kSpacer + (SK_ARRAY_COUNT(gScales) - i - 1) * (fImage->height() + kSpacer);
}
this->draw(canvas, xOff, yOff, width, fImage->height());
}
}
private:
static constexpr int kImageSize = 256;
static constexpr int kSpacer = 10;
static constexpr int kNumVertImages = 5;
sk_sp<SkImage> fImage;
SkSamplingOptions fSampling;
using INHERITED = GM;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new AnisotropicGM;)
} // namespace skiagm