LibGfx/TIFF: Add support for tiled images

A tile is basically a strip with a user-defined width. With that in
mind, adding support for them is quite straightforward. As a lot the
common code was named after 'strips', to avoid future confusion I
renamed everything that interact with either strips or tiles to a
global term: 'segment'.

Note that tiled images are supposed to always have a 'TileOffsets' tag
instead of 'StripOffset'. However, this doesn't seem to be enforced by
encoders, so we support having either of them indifferently.

The test case was generated with the following Python script:

import pyvips

img = pyvips.Image.new_from_file('deflate.tiff')
img.write_to_file('tiled.tiff',
                  compression=pyvips.ForeignTiffCompression.DEFLATE,
                  tile=True, tile_width=64, tile_height=64)
This commit is contained in:
Lucas CHOLLET 2024-02-09 21:35:33 -05:00 committed by Jelle Raaijmakers
commit 8e21bbf7bf
Notes: sideshowbarker 2024-07-18 00:54:03 +09:00
3 changed files with 57 additions and 30 deletions

View file

@ -776,6 +776,18 @@ TEST_CASE(test_tiff_cmyk)
EXPECT_NE(frame.image->get_pixel(60, 75), Gfx::Color::NamedColor::White);
}
TEST_CASE(test_tiff_tiled)
{
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/tiled.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), Gfx::Color::NamedColor::White);
EXPECT_EQ(frame.image->get_pixel(60, 75), Gfx::Color::NamedColor::Red);
}
TEST_CASE(test_tiff_invalid_tag)
{
auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("tiff/invalid_tag.tiff"sv)));