At least the data format of the ARGB chunk is better documented than the data format of the IMAG chunk. Although IMAG is better understood now.
True.
There is some additional information provided by PeterK about the flags in the FACE chunk where bit 0 means frameless & bit 1 means ARGB data is present. Although searching for the 'ARGB' chunkID works just as well.
Yeah, I knew. Sorry for that. I should have linked to the post of PeterK at EAB
We have to be able to decode the ARGB chunk data for AROS ARGB Icons which are Classic Icons with IFF data with IMAG chunks & ARGB data chunks. Also for OS41 which are Classic Icons with IFF data with a FACE chunk but no IMAG chunks followed by ARGB data chunks.
The picture posted in my reply #45 is such ARGB icon.
The ARGB data can be exported as PNG images.
I'm still thinking about adding support for (optional) saving them as 32-bit ILBM as well.
Although I can fire up AROS and/or classic to verify a few things I had (perhaps still have?) a difficult time finding a viewer for Linux that is capable of viewing particular ILBM files. For now I settled with XNView but initially resorted to an online ILBM viewer. Most viewers do not support bitmap depth schemes other than 1,2,4 or 8 planes, not to mention crashing completely when not supplying a full CMAP (the IFF standard does allow it).
So I had to waste a few days figuring out whether or not my code was doing things wrong or the used viewer was in error
Next on the list is adding (RLE) compression but it is not the most important feature to me to add right now, I rather focus on something you wrote in your post that you wrote right below the one I quoted, namely being able to access all icon related image data in a way that makes the code a bit more bearable to read as it is currently a giant mess