RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 20:57:35 +00:00
Code Issues Activity Actions

LibGfx/TIFF: Apply the HorizontalDifferencing on the alpha channel

Browse source 
When present, the alpha channel is also affected by the horizontal
differencing predictor.

The test case was generated with GIMP with the following steps:
 - Open an RGB image
 - Add a transparency layer
 - Export as TIFF with the LZW compression scheme
This commit is contained in:
Lucas CHOLLET 2024-01-22 21:19:42 -05:00 • committed by Andrew Kaster
parent 0e6d87fe83
commit 1faf9bb44f
3 changed files with 14 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

12
Tests/LibGfx/TestImageDecoder.cpp
View file

@ -676,6 +676,18 @@ TEST_CASE(test_tiff_palette_alpha)
EXPECT_EQ(frame.image->get_pixel(60, 75), Gfx::Color::NamedColor::Red);
}
TEST_CASE(test_tiff_alpha_predictor)
{
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/alpha_predictor.tiff"sv)));
EXPECT(Gfx::TIFFImageDecoderPlugin::sniff(file->bytes()));
auto plugin_decoder = TRY_OR_FAIL(Gfx::TIFFImageDecoderPlugin::create(file->bytes()));
auto frame = TRY_OR_FAIL(expect_single_frame_of_size(*plugin_decoder, { 400, 300 }));
EXPECT_EQ(frame.image->get_pixel(0, 0).alpha(), 255);
EXPECT_EQ(frame.image->get_pixel(60, 75), Gfx::Color::NamedColor::Red);
}
TEST_CASE(test_tiff_16_bits)
{
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/16_bits.tiff"sv)));