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/*
* 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"
#include "Resources.h"
#include "SkGradientShader.h"
DEF_SIMPLE_GM(gamma, canvas, 500, 200) {
SkPaint p;
const SkScalar sz = 50.0f;
const int szInt = SkScalarTruncToInt(sz);
const SkScalar tx = sz + 5.0f;
const SkRect r = SkRect::MakeXYWH(0, 0, sz, sz);
SkShader::TileMode rpt = SkShader::kRepeat_TileMode;
SkBitmap ditherBmp;
ditherBmp.allocN32Pixels(2, 2);
SkPMColor* pixels = reinterpret_cast<SkPMColor*>(ditherBmp.getPixels());
pixels[0] = pixels[3] = SkPackARGB32(0xFF, 0xFF, 0xFF, 0xFF);
pixels[1] = pixels[2] = SkPackARGB32(0xFF, 0, 0, 0);
SkBitmap linearGreyBmp;
SkImageInfo linearGreyInfo = SkImageInfo::MakeN32(szInt, szInt, kOpaque_SkAlphaType,
kLinear_SkColorProfileType);
linearGreyBmp.allocPixels(linearGreyInfo);
linearGreyBmp.eraseARGB(0xFF, 0x7F, 0x7F, 0x7F);
SkBitmap srgbGreyBmp;
SkImageInfo srgbGreyInfo = SkImageInfo::MakeN32(szInt, szInt, kOpaque_SkAlphaType,
kSRGB_SkColorProfileType);
srgbGreyBmp.allocPixels(srgbGreyInfo);
srgbGreyBmp.eraseARGB(0xFF, 0xBC, 0xBC, 0xBC);
SkPaint textPaint;
textPaint.setColor(SK_ColorWHITE);
// Helpers:
auto advance = [&]() {
canvas->translate(tx, 0);
p.reset();
};
auto nextRect = [&](const char* label, const char* label2) {
canvas->drawRect(r, p);
canvas->drawText(label, strlen(label), 0, sz + textPaint.getFontSpacing(), textPaint);
if (label2) {
canvas->drawText(label2, strlen(label2), 0, sz + 2 * textPaint.getFontSpacing(),
textPaint);
}
advance();
};
auto nextBitmap = [&](const SkBitmap& bmp, const char* label) {
canvas->drawBitmap(bmp, 0, 0);
canvas->drawText(label, strlen(label), 0, sz + textPaint.getFontSpacing(), textPaint);
advance();
};
auto nextXferRect = [&](SkColor srcColor, SkXfermode::Mode mode, SkColor dstColor) {
p.setColor(dstColor);
canvas->drawRect(r, p);
p.setColor(srcColor);
p.setXfermodeMode(mode);
canvas->drawRect(r, p);
SkString srcText = SkStringPrintf("%08X", srcColor);
SkString dstText = SkStringPrintf("%08X", dstColor);
canvas->drawText(srcText.c_str(), srcText.size(), 0, sz + textPaint.getFontSpacing(),
textPaint);
const char* modeName = SkXfermode::ModeName(mode);
canvas->drawText(modeName, strlen(modeName), 0, sz + 2 * textPaint.getFontSpacing(),
textPaint);
canvas->drawText(dstText.c_str(), dstText.size(), 0, sz + 3 * textPaint.getFontSpacing(),
textPaint);
advance();
};
// Necessary for certain Xfermode tests to work (ie some of them output white @ 50% alpha):
canvas->clear(SK_ColorBLACK);
// *Everything* should be perceptually 50% grey. Only the first rectangle
// is guaranteed to draw that way, though.
canvas->save();
// Black/white dither, pixel perfect. This is ground truth.
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kNone_SkFilterQuality);
nextRect("Dither", "Reference");
// Black/white dither, sampled at half-texel offset. Tests bilerp.
// NOTE: We need to apply a non-identity scale and/or rotation to trick
// the raster pipeline into *not* snapping to nearest.
SkMatrix offsetMatrix = SkMatrix::Concat(
SkMatrix::MakeScale(-1.0f), SkMatrix::MakeTrans(0.5f, 0.0f));
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt, &offsetMatrix));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Dither", "Bilerp");
// Black/white dither, scaled down by 2x. Tests minification.
SkMatrix scaleMatrix = SkMatrix::MakeScale(0.5f);
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt, &scaleMatrix));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Dither", "Scale");
// 50% grey via paint color.
p.setColor(0xff7f7f7f);
nextRect("Color", 0);
// Black -> White gradient, scaled to sample just the middle.
// Tests gradient interpolation.
SkPoint points[2] = {
SkPoint::Make(0 - (sz * 10), 0),
SkPoint::Make(sz + (sz * 10), 0)
};
SkColor colors[2] = { SK_ColorBLACK, SK_ColorWHITE };
p.setShader(SkGradientShader::MakeLinear(points, colors, nullptr, 2,
SkShader::kClamp_TileMode));
nextRect("Gradient", 0);
// 50% grey from linear bitmap, with drawBitmap
nextBitmap(linearGreyBmp, "Lnr BMP");
// 50% grey from sRGB bitmap, with drawBitmap
nextBitmap(srgbGreyBmp, "sRGB BMP");
// Bitmap wrapped in a shader (linear):
p.setShader(SkShader::MakeBitmapShader(linearGreyBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Lnr BMP", "Shader");
// Bitmap wrapped in a shader (sRGB):
p.setShader(SkShader::MakeBitmapShader(srgbGreyBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("sRGB BMP", "Shader");
// Carriage return.
canvas->restore();
canvas->translate(0, 2 * sz);
const U8CPU sqrtHalf = 0xB4;
const SkColor sqrtHalfAlpha = SkColorSetARGB(sqrtHalf, 0, 0, 0);
const SkColor sqrtHalfWhite = SkColorSetARGB(0xFF, sqrtHalf, sqrtHalf, sqrtHalf);
// Xfermode tests, all done off-screen so certain modes work...
canvas->saveLayer(nullptr, nullptr);
nextXferRect(0x7fffffff, SkXfermode::kSrcOver_Mode, SK_ColorBLACK);
nextXferRect(0x7f000000, SkXfermode::kSrcOver_Mode, SK_ColorWHITE);
nextXferRect(SK_ColorBLACK, SkXfermode::kDstOver_Mode, 0x7fffffff);
nextXferRect(SK_ColorWHITE, SkXfermode::kSrcIn_Mode, 0x7fff00ff);
nextXferRect(0x7fff00ff, SkXfermode::kDstIn_Mode, SK_ColorWHITE);
nextXferRect(sqrtHalfWhite, SkXfermode::kSrcIn_Mode, sqrtHalfAlpha);
nextXferRect(sqrtHalfAlpha, SkXfermode::kDstIn_Mode, sqrtHalfWhite);
nextXferRect(0xff3f3f3f, SkXfermode::kPlus_Mode, 0xff3f3f3f);
nextXferRect(sqrtHalfWhite, SkXfermode::kModulate_Mode, sqrtHalfWhite);
canvas->restore();
canvas->restore();
}
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