Does not change testing on other files, but fixes a case which previously made PIL collapse.
The Bitmap was a 1x1 RGBA and provoked an exception in PIL, but every Image viewer can load it.
Fixed code with comparison of header size, compression type and loading type of masks and fixed it.
Error happening in Python 3.x with P images:
in original code, palette data was created from a list of bytestrings. Changed to a full bytestring.
- `b"".join(list of bytestrings)` works in python 2.7 and 3.x
- `b"".join(bytestring)` works in python 2.7 but fails in python 3.x
No need to `join` anymore. Works in 3.x
Fixed loading of all types of provided images (+rgba). Added edge case where the header is reported as 40 bytes long with BITFIELDS (they start past the 40 bytes of the header). Loading fails for RLE, but IIRC, they're unsupported so it's normal.
It appears that
{{{
The handling of 1bpp bitmaps is a little complicated.
When reading 1bpp bitmaps, the palette is ignored.
1's are considered foreground, and they are considered black.
0's are considered background, and they are considered white.
}}}
so the raw mode has to be `1;I`
PIL choked on perfectly valid BMP files (32 bits with Alpha). It could not handle valid RGBA masks to determine the raw format.
To clarify things, I:
- Rewrote the `BmpImagePlugin.BmpImageFile` class to be far more readable
- Made error messages more explicit (e.g. say that RLE bitmaps are unsupported)
- Made a readable dict to contain BMP header information
- Kept the existing security checks
- Instead of reading palette info by chunks of 3/4 bytes, read the whole palette info at once and parse the data.
- Now works with BMPv4/5 with Alpha (and can be exported to alpha PNG for example)
- Tested load and save with RGB24, RGB8, RGB8L, RGB32 and RGBA32.
- Tested with one bogus file. File not accepted, as expected.
I wanted to test more BMP formats, but I could not find that many images.
But for all the types I tested, it worked flawlessly.
