LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-11-10 13:00:29 +03:00
Code Issues Packages Projects Releases Wiki Activity

LibPDF: Support drawing images with 16 bits per channel

Browse Source 
This uses the tried-and-true "throw away the lower 8 bits" technique
for now. This lets us render  Tests/LibPDF/wide-gamut-only.pdf.
This commit is contained in:
Nico Weber 2024-01-12 09:02:50 -05:00 committed by Andrew Kaster
parent b47695c87e
commit f4ee9a2333
Notes: sideshowbarker 2024-07-17 17:06:59 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/f4ee9a2333
Pull-request: https://github.com/SerenityOS/serenity/pull/22718
Reviewed-by: https://github.com/ADKaster ✅
1 changed files with 16 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
Userland/Libraries/LibPDF/Renderer.cpp
View File

@ -1092,23 +1092,32 @@ PDFErrorOr<Renderer::LoadedImage> Renderer::load_image(NonnullRefPtr<StreamObjec
int const n_components = color_space->number_of_components();
Vector<u8> upsampled_storage;
Vector<u8> resampled_storage;
if (bits_per_component < 8) {
UpsampleMode mode = color_space->family() == ColorSpaceFamily::Indexed ? UpsampleMode::StoreValuesUnchanged : UpsampleMode::UpsampleTo8Bit;
upsampled_storage = upsample_to_8_bit(content, width * n_components, bits_per_component, mode);
content = upsampled_storage;
resampled_storage = upsample_to_8_bit(content, width * n_components, bits_per_component, mode);
content = resampled_storage;
bits_per_component = 8;
if (is_image_mask) {
// "a sample value of 0 marks the page with the current color, and a 1 leaves the previous contents unchanged."
// That's opposite of the normal alpha convention, and we're upsampling masks to 8 bit and use that as normal alpha.
for (u8& byte : upsampled_storage)
for (u8& byte : resampled_storage)
byte = ~byte;
}
}
} else if (bits_per_component == 16) {
if (color_space->family() == ColorSpaceFamily::Indexed)
return Error(Error::Type::RenderingUnsupported, "16 bpp indexed images not yet supported");
if (bits_per_component == 16) {
return Error(Error::Type::RenderingUnsupported, "16 bpp images not yet supported");
// PDF 1.7 spec, 4.8.2 Sample Representation:
// "units of 16 bits are given with the most significant byte first"
// FIXME: Eventually use all 16 bits instead of throwing away the lower 8 bits.
resampled_storage.ensure_capacity(content.size() / 2);
for (size_t i = 0; i < content.size(); i += 2)
resampled_storage.append(content[i]);
content = resampled_storage;
bits_per_component = 8;
}
Vector<float> decode_array;