I noticed some peculiarities to loading tilesets in my game in both text blitters & as backdrop objects (via the active picture object). I have both programmed to accomplish the same visual display, but there is a nonsubtle difference in the palette of the two, causing a distinct graphical boundary- the text blitter's image is discolored, whereas the active picture object looks exactly like the original image.
Yet, I found out that if I used an *uncompressed* PNG file as my tileset instead, it would have no discoloration at all. So what I am figuring from this is that theres some issue with the scheme the text blitter object is using to read from compressed PNG files (I'm using the standard compression on irfanview, set to 0 vs 1,2,3...9 for comparison).
Now please forgive the gigantic images, but they have to be this big to make the difference obvious. I've got a single band of backdrops running through a large rectangle of text blitter image.
Using a compressed (1 compression) PNG @ 13 KB:
Using a noncompressed PNG @ 130 KB:
Anyway, I gotta stress that both tiles are being loaded from the same tileset base image. There just appears to be some inconsistency on how the two object load the base files, yet when no compression is involved they appear virtually exactly the same. So while I try to figure out a workaround to this, I thought I'd just point it out in case its some kind of bug or whatever