LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-09-20 01:37:39 +03:00
Code Issues Packages Projects Releases Wiki Activity

LibGfx/WebPLossless: Make width_bits reading look more like in the spec

Browse Source 
No behavior change.
This commit is contained in:
Nico Weber 2024-05-07 07:30:05 -04:00 committed by Tim Flynn
parent c1b289c144
commit 26b3e31f2e
Notes: sideshowbarker 2024-07-16 22:58:46 +09:00 
Author: https://github.com/nico
Commit: https://github.com/SerenityOS/serenity/commit/26b3e31f2e
Pull-request: https://github.com/SerenityOS/serenity/pull/24249
1 changed files with 7 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
Userland/Libraries/LibGfx/ImageFormats/WebPLoaderLossless.cpp
View File

@ -875,13 +875,16 @@ ErrorOr<NonnullOwnPtr<ColorIndexingTransform>> ColorIndexingTransform::read(Litt
auto palette_bitmap = TRY(decode_webp_chunk_VP8L_image(ImageKind::EntropyCoded, BitmapFormat::BGRA8888, palette_image_size, bit_stream));
// "When the color table is small (equal to or less than 16 colors), several pixels are bundled into a single pixel..."
int pixels_per_pixel = 1;
int width_bits;
if (color_table_size <= 2)
pixels_per_pixel = 8;
width_bits = 3;
else if (color_table_size <= 4)
pixels_per_pixel = 4;
width_bits = 2;
else if (color_table_size <= 16)
pixels_per_pixel = 2;
width_bits = 1;
else
width_bits = 0;
int pixels_per_pixel = 1 << width_bits;
// "The color table is always subtraction-coded to reduce image entropy. [...] In decoding, every final color in the color table
// can be obtained by adding the previous color component values by each ARGB component separately,