We did not load the alpha channel when loading Photoshop patterns.
The Photoshop pattern format doesn't tell you whether a pattern has
an alpha channel. You can only find out by reading the color channels
first and then checking if there is enough room for another channel.
In addition to that there is also an 88-byte empty space before the
alpha channel.
To fix this, we now always add an alpha channel to the pattern and
then check if there is enough room. We separated the code inside the
channel reading loop into a separate function, which is now also
called if an alpha channel is detected. If none is detected, we
initialize that channel to 255 (fully opaque).
Besides this a few minor error checking improvements were made:
- Only show the unsupported color mode text once per pattern file.
- Only accept 8-bit color channels, other values will print a console
warning.
a8339021f8