diff options
Diffstat (limited to 'gm')
| -rw-r--r-- | gm/gamma.cpp | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/gm/gamma.cpp b/gm/gamma.cpp new file mode 100644 index 0000000000..003061baeb --- /dev/null +++ b/gm/gamma.cpp @@ -0,0 +1,171 @@ +/* + * 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::CreateBitmapShader( + ditherBmp, rpt, rpt))->unref(); + 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::CreateBitmapShader( + ditherBmp, rpt, rpt, &offsetMatrix))->unref(); + 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::CreateBitmapShader( + ditherBmp, rpt, rpt, &scaleMatrix))->unref(); + 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::CreateLinear( + points, colors, nullptr, 2, SkShader::kClamp_TileMode))->unref(); + 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::CreateBitmapShader(linearGreyBmp, rpt, rpt))->unref(); + p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality); + nextRect("Lnr BMP", "Shader"); + + // Bitmap wrapped in a shader (sRGB): + p.setShader(SkShader::CreateBitmapShader(srgbGreyBmp, rpt, rpt))->unref(); + 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(); +} |