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Delphi & Greyscaling Alpha Blended PNG's

Posted: Tue Jan 31, 2006 7:19 pm
by mkeeley
Hello again,

I'm stuck with another problem. I'm trying to greyscale and then lighten using Gamma correction an alpha-blended PNG image. I then want to save it out as a greyscaled alpha-blended png.

I've tried using the LoadParam ColorModel := GFL_GREY, but the output is still coloured but lighter because of the Gammea correction.

I also tried loading it normally and grey scaling, setting it back to RGB. But the gey scaling kills the alpha channel and the output has a solid black background.

Anyone have any ideas?

Also is this group still being monitored by Pierre as there doesn't seem any replies since the end of Nov. Would I be better off e-mailing Pierre directly?

Thanks

Marc Keeley

Re: Delphi & Greyscaling Alpha Blended PNG's

Posted: Wed Feb 01, 2006 11:17 am
by xnview
mkeeley wrote:Hello again,

I'm stuck with another problem. I'm trying to greyscale and then lighten using Gamma correction an alpha-blended PNG image. I then want to save it out as a greyscaled alpha-blended png.

I've tried using the LoadParam ColorModel := GFL_GREY, but the output is still coloured but lighter because of the Gammea correction.
ColorModel is used for RAW loading
I also tried loading it normally and grey scaling, setting it back to RGB. But the gey scaling kills the alpha channel and the output has a solid black background.
Anyone have any ideas?
Yes, converting in greyscale delete alpha channel.
Your original file is in 32bits?
Also is this group still being monitored by Pierre as there doesn't seem any replies since the end of Nov. Would I be better off e-mailing Pierre directly?
Sorry i was very busy with next release of xnview...

Posted: Wed Feb 01, 2006 7:41 pm
by mkeeley
Hello Pierre


Yes the alpha-blended PNG is 32 bit, just want to grey scale it and lighten it with some Gamma correction whilst still keeping the alpha-blending.

Marc

Posted: Wed Feb 01, 2006 8:42 pm
by xnview
mkeeley wrote:Hello Pierre


Yes the alpha-blended PNG is 32 bit, just want to grey scale it and lighten it with some Gamma correction whilst still keeping the alpha-blending.
So you must make your own greyscale function to keep alpha... Sorry

Posted: Wed Feb 01, 2006 9:30 pm
by Guest
OK, thanks I'll have to do some investigation.

Marc