Hi Daniel,
I cannot reproduce the effect you mentioned.
I just tested it this way:
I imported 2 tif-images into director, one of them (img1) containing an
alpha channel, which I had created in Photoshop.
Then I went:
img1 = member("img1").image.duplicate()
img2 = member("img2).image.duplicate()
img1.useAlpha = TRUE
img2.copyPixels(img1, img2.rect, img1.rect)
x = new(#bitmap)
x.name = "result"
x.image = img2
The result in member "result" was a perfect blend of both.
I am on Dir 8.5.1 WIN, the color depth of my video card is set to 32.
Regards
Michael
-----Ursprungliche Nachricht-----
Von: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Auftrag von Daniel Nelson
Gesendet: Donnerstag, 25. September 2003 06:11
An: [EMAIL PROTECTED]
Betreff: Re: AW: <lingo-l> copyPixels and alpha channel
Hi Michael,
My experimentation with copyPixels() does not achieve a true alpha
composite. Using the example you have given, anywhere there is positive
alpha data in img1 completely overwrites the image data in img2. ie: if a
pixel in img1 was at 10% transparent, and the corresponding pixel
in img2 was at 100%, then the result of the copypixel was the img1 pixel at
10%, instead of what it should be, which is the img2 pixel tinted by the
img1 pixel.
I've posted an example of the difference in functionality between my
smartAlphaCopyPixels() and copyPixels() for your reference (click the
different sets of words to perform the corresponding composite):
http://www.bluejade.com/public_resources/director/copypixels.html
Regards,
Daniel
Michael von Aichberger wrote:
> > In my own experimentation, I was unable to use copyPixels to
> properly composite two bitmaps with alpha channels. Has
> anyone here used copyPixels successfully?
>
> yes, I have.
>
> To copy img1 with its alpha channel into img2 use
>
> img1.useAlpha = TRUE
> img2.copyPixels(img1, img2.rect, img1.rect)
>
> Does that help?
>
> Regards
> Michael
>
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