When using the BMP encoding, ICO images are expected to contain a 1-bit
mask for transparency. Regardless an alpha channel is already included
in the image, the mask is always required. As stated here[1], the
mask is used to provide shadow around the image.
Unfortunately, it seems that some encoder do not include that second
transparency mask. So let's read that mask only if some data is still
remaining after decoding the image.
The test case has been generated by truncating the 64 last bytes
(originally dedicated to the mask) from the `serenity.ico` file and
changing the declared size of the image in the ICO header. The size
value is stored at the offset 0x0E in the file and I changed the value
from 0x0468 to 0x0428.
[1]: https://devblogs.microsoft.com/oldnewthing/20101021-00/?p=12483
This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).
This commit is auto-generated:
$ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
Meta Ports Ladybird Tests Kernel)
$ perl -pie 's/\bDeprecatedString\b/ByteString/g;
s/deprecated_string/byte_string/g' $xs
$ clang-format --style=file -i \
$(git diff --name-only | grep \.cpp\|\.h)
$ gn format $(git ls-files '*.gn' '*.gni')
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
The ideal size is the size the user will display the image. Raster
formats should ignore this parameter, but vector formats can use
it to generate a bitmap of the ideal size.
There was a TODO questioning whether breaking on >4bpp images
was the correct behaviour when RLE4 was detected. There is no
indication in the spec that RLE4 can be used with anything >4bpp,
so I believe this doesn't require additional follow-up.
MS Spec:
https://learn.microsoft.com/en-us/windows/win32/gdi/bitmap-compression
