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LibGfx/JPEG: Add YCCK and CMYK to RGB color transformations

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It means that we now fully support JPEGs with four components :^).
This commit is contained in:
Lucas CHOLLET 2023-03-21 18:24:37 -04:00 • committed by Linus Groh
parent 9cbed7b359
commit 6bc30099f2
1 changed files with 98 additions and 8 deletions
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106
Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
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@ -1356,6 +1356,100 @@ static void ycbcr_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>&
}
}
static void invert_colors_for_adobe_images(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
{
if (!context.color_transform.has_value())
return;
// From libjpeg-turbo's libjpeg.txt:
// https://github.com/libjpeg-turbo/libjpeg-turbo/blob/main/libjpeg.txt
// CAUTION: it appears that Adobe Photoshop writes inverted data in CMYK JPEG
// files: 0 represents 100% ink coverage, rather than 0% ink as you'd expect.
// This is arguably a bug in Photoshop, but if you need to work with Photoshop
// CMYK files, you will have to deal with it in your application.
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
for (u8 vfactor_i = 0; vfactor_i < context.vsample_factor; ++vfactor_i) {
for (u8 hfactor_i = 0; hfactor_i < context.hsample_factor; ++hfactor_i) {
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
for (u8 i = 0; i < 8; ++i) {
for (u8 j = 0; j < 8; ++j) {
macroblocks[mb_index].r[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].r[i * 8 + j];
macroblocks[mb_index].g[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].g[i * 8 + j];
macroblocks[mb_index].b[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].b[i * 8 + j];
macroblocks[mb_index].k[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].k[i * 8 + j];
}
}
}
}
}
}
}
static void cmyk_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
{
invert_colors_for_adobe_images(context, macroblocks);
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) {
for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) {
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
i32* c = macroblocks[mb_index].y;
i32* m = macroblocks[mb_index].cb;
i32* y = macroblocks[mb_index].cr;
i32* k = macroblocks[mb_index].k;
for (u8 i = 0; i < 8; ++i) {
for (u8 j = 0; j < 8; ++j) {
u8 const pixel = i * 8 + j;
static constexpr auto max_value = NumericLimits<u8>::max();
auto const black_component = max_value - k[pixel];
int const r = ((max_value - c[pixel]) * black_component) / max_value;
int const g = ((max_value - m[pixel]) * black_component) / max_value;
int const b = ((max_value - y[pixel]) * black_component) / max_value;
c[pixel] = clamp(r, 0, max_value);
m[pixel] = clamp(g, 0, max_value);
y[pixel] = clamp(b, 0, max_value);
}
}
}
}
}
}
}
static void ycck_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
{
// 7 - Conversions between colour encodings
// YCCK is obtained from CMYK by converting the CMY channels to YCC channel.
// To convert back into RGB, we only need the 3 first components, which are baseline YCbCr
ycbcr_to_rgb(context, macroblocks);
// RGB to CMYK, as mentioned in https://www.smcm.iqfr.csic.es/docs/intel/ipp/ipp_manual/IPPI/ippi_ch15/functn_YCCKToCMYK_JPEG.htm#functn_YCCKToCMYK_JPEG
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
for (u8 vfactor_i = 0; vfactor_i < context.vsample_factor; ++vfactor_i) {
for (u8 hfactor_i = 0; hfactor_i < context.hsample_factor; ++hfactor_i) {
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
for (u8 i = 0; i < 8; ++i) {
for (u8 j = 0; j < 8; ++j) {
macroblocks[mb_index].r[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].r[i * 8 + j];
macroblocks[mb_index].g[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].g[i * 8 + j];
macroblocks[mb_index].b[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].b[i * 8 + j];
}
}
}
}
}
}
cmyk_to_rgb(context, macroblocks);
}
static ErrorOr<void> handle_color_transform(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
{
if (context.color_transform.has_value()) {
@ -1365,8 +1459,7 @@ static ErrorOr<void> handle_color_transform(JPEGLoadingContext const& context, V
switch (*context.color_transform) {
case ColorTransform::CmykOrRgb:
if (context.components.size() == 4) {
// FIXME: implement CMYK
dbgln("CMYK isn't supported yet");
cmyk_to_rgb(context, macroblocks);
} else if (context.components.size() == 3) {
// Note: components.size() == 3 means that we have an RGB image, so no color transformation is needed.
} else {
@ -1377,8 +1470,7 @@ static ErrorOr<void> handle_color_transform(JPEGLoadingContext const& context, V
ycbcr_to_rgb(context, macroblocks);
break;
case ColorTransform::YCCK:
// FIXME: implement YCCK
dbgln("YCCK isn't supported yet");
ycck_to_rgb(context, macroblocks);
break;
}
@ -1389,10 +1481,8 @@ static ErrorOr<void> handle_color_transform(JPEGLoadingContext const& context, V
// - 1 components means grayscale
// - 3 components means YCbCr
// - 4 components means CMYK
if (context.components.size() == 4) {
// FIXME: implement CMYK
dbgln("CMYK isn't supported yet");
}
if (context.components.size() == 4)
cmyk_to_rgb(context, macroblocks);
if (context.components.size() == 3)
ycbcr_to_rgb(context, macroblocks);