BMP files encode the direction of the rows with the sign of the height.
Our BMP decoder already makes all the proper checks, however when
constructing the Gfx::Bitmap, didn't actually make the height positive.
Boog neutralized :^)
This was the only remaining codec that produced IndexedN bitmaps.
By removing them, we'll be able to get rid of those formats and simplify
the Bitmap and Painter classes.
It is unlikely this is needed anymore, and as pointed out things should
now safely return OOM if the bitmap is too large to allocate.
Also, no recently added decoders respected this limit anyway.
Fixes#20872
IFF was a generic container fileformat that was popular on the Amiga
since it was the only file format supported by Deluxe Paint.
ILBM is an image format popular in the late eighties/nineties
that uses the IFF container.
This is a very first version of the decoder that only supports
(byterun) compressed files with bpp <= 8.
Only the minimal chunks are decoded: CMAP, BODY, BMHD.
I am planning to add support for the following variants:
- EHB (32 colours + lighter 32 colours)
- HAM6 / HAM8 (special mode that allowed to display the whole Amiga
4096 colours / 262 144 colours palette)
- TrueColor (24bit)
Things that could be fun to do:
- Still images could be animated using color cycle information
Due to the way JPEG XL encodes its lossless images, it is sometimes
interesting to embed a large image and crop the result at the end. This
patch adds the functionality to crop a frame.
Note that JPEG XL supports image composition (almost like layers in
image editing software programs) and I tried to make these changes be
a step toward image composing. It's a small step as we are still unable
to read multiple frames, and we only support the `kReplace` blending
mode.
The image was previously managed as an output parameter of the
`read_frame` function. This reorganisation also brings us closer to the
spec. As it is specified that each frame have its own image that will
later on compose a greater bitmap.
While being way less frequent than for classical JPEG images, JPEG XL
images can use the YCbCr color space. Supporting it makes us properly
decode the "The Smoke Machine" image on https://jpegxl.info/jxl-art.html
On top of the Brotli/ANS compression, the entropy stream can have
another compression layer, this time using LZ77. This patch adds support
for this last layer, which makes us decode the `lz77_flower` test. This
double-compression is also often used for ICC profiles.
