Controlling format of PNG export?

Chipp Walters chipp at chipp.com
Wed Apr 30 05:09:01 EDT 2003


Ben,

I've got a small free screencapture utility built in Rev at

http://www.altuit.com/hemtools/dls/hemtools15setup.exe

and used it to test you supposition. Indeed, when i capture an image (WinXP)
with only a few colors (like this text message) and save it as a PNG, it
shows up as INDEXED color in Photoshop (256 colors), but when I capture
something with more than 256 colors, it shows up in Photoshop as a full
32-bit (with Alpha) image. HMMMMM....it seems you are correct.

Did you try and set the alphadata before exporting? Or...copying the
imageData and alphadata to a 'real 32-bit' image, then export? Just some
thoughts...

best of luck;-)

Chipp

> > Evidently, the MC engine, asked to export a PNG from a 32-bit +
> mask image,
> > is cunningly inspecting it and deciding that there are no more than 256
> > distinct colours, and therefore choosing to optimise the file.  I've no
> > reason to think that these aren't perfectly valid PNG files
> (PhotoShop at
> > least seems to see the transparency)




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