float Float16ToFloat(const uint16_t& f16) { union FloatUIntUnion { uint32_t fUInt; float fFloat; }; FloatUIntUnion magic = {126 << 23}; FloatUIntUnion o; if (((f16 >> 10) & 0x001f) == 0) { o.fUInt = magic.fUInt + (f16 & 0x03ff); o.fFloat -= magic.fFloat; } else { o.fUInt = (f16 & 0x03ff) << 13; if (((f16 >> 10) & 0x001f) == 0x1f) o.fUInt |= (255 << 23); else o.fUInt |= ((127 - 15 + ((f16 >> 10) & 0x001f)) << 23); } o.fUInt |= ((f16 >> 15) << 31); return o.fFloat; } SkString printSkImage(sk_sp input) { // find out the color space SkColorSpace* color_space = input->colorSpace(); SkString str; if (input->alphaType() == kPremul_SkAlphaType) str.append("Premul"); else str.append("Unpremul"); SkColorType color_type = kRGBA_8888_SkColorType; SkImageInfo info = SkImageInfo::Make(input->width(), input->height(), color_type, input->alphaType(), input->refColorSpace()); if (info.bytesPerPixel() == 4) { std::unique_ptr read_pixels( new uint8_t[input->width() * input->height() * info.bytesPerPixel()]()); input->readPixels(info, read_pixels.get(), input->width() * info.bytesPerPixel(), 0, 0); for (int i = 0; i < input->width() * input->height(); i++) { if (i > 0 && i % input->width() == 0) str.append("\n"); str.append("["); for (int j = 0; j < info.bytesPerPixel(); j++) str.appendf(" %3d", (int)(read_pixels[i * info.bytesPerPixel() + j])); str.append(" ]"); } } else { std::unique_ptr read_pixels( new uint16_t[input->width() * input->height() * 4]()); input->readPixels(info, read_pixels.get(), input->width() * info.bytesPerPixel(), 0, 0); for (int i = 0; i < input->width() * input->height(); i++) { str.append("\n"); str.append("["); for (int j = 0; j < 4; j++) str.appendf("%1.5f%s", Float16ToFloat(read_pixels[i * 4 + j]), j == 3 ? "" : ", "); str.append("]"); } } return str; } #define DRAW(x, y, c) do { SkPaint pc; pc.setColor(c); offscreen->getCanvas()->drawRect(SkRect::MakeXYWH(x, y, 1, 1), pc); } while (0) void draw(SkCanvas* canvas) { SkImageInfo info = SkImageInfo::Make( 4, 4, SkColorType::kN32_SkColorType, SkAlphaType::kUnpremul_SkAlphaType, SkColorSpace::MakeSRGB()); sk_sp offscreen = SkSurface::MakeRaster(info); DRAW(0, 0, SkPackARGB32(255, 50, 100, 150)); /* DRAW(1, 0, SkPackARGB32(255, 0, 255, 0)); DRAW(2, 0, SkPackARGB32(255, 0, 0, 255)); DRAW(3, 0, SkPackARGB32(255, 0, 0, 0)); DRAW(0, 1, SkPackARGB32(255, 155, 27, 27)); DRAW(1, 1, SkPackARGB32(255, 27, 155, 27)); DRAW(2, 1, SkPackARGB32(255, 27, 27, 155)); DRAW(3, 1, SkPackARGB32(255, 27, 27, 27)); DRAW(0, 2, SkPackARGB32(128, 155, 27, 27)); DRAW(1, 2, SkPackARGB32(128, 27, 155, 27)); DRAW(2, 2, SkPackARGB32(128, 27, 27, 155)); DRAW(3, 2, SkPackARGB32(128, 27, 27, 27)); DRAW(0, 3, SkPackARGB32(128, 226, 31, 31)); DRAW(1, 3, SkPackARGB32(128, 31, 226, 31)); DRAW(2, 3, SkPackARGB32(128, 31, 31, 226)); DRAW(3, 3, SkPackARGB32(128, 31, 31, 31)); */ sk_sp img1 = offscreen->makeImageSnapshot(); sk_sp srgb = SkColorSpace::MakeSRGB(); sk_sp p3 = SkColorSpace::MakeRGB( SkNamedTransferFn::kSRGB, SkNamedGamut::kDisplayP3); static constexpr skcms_TransferFunction k2Dot4 = { 2.4f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f }; sk_sp rec2020 = SkColorSpace::MakeRGB( k2Dot4, SkNamedGamut::kRec2020); SkDebugf("Input: \n%s\n", printSkImage(img1).c_str()); SkDebugf("srgb: \n%s\n", printSkImage(img1->makeColorSpace(srgb)).c_str()); SkDebugf("p3: \n%s\n", printSkImage(img1->makeColorSpace(p3)).c_str()); SkDebugf("rec2020:\n%s\n", printSkImage(img1->makeColorSpace(rec2020)).c_str()); }