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Index › Programming Questions & Help › Other Libraries › pasting transparent img
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pasting transparent img (Read 1619 times)
haliphax
pasting transparent img
Feb 22nd, 2007, 4:55am  
so.. it's obvious that i could just convert any images i need transparent sections in to .gif, but i'd rather keep a lot of them in other formats.

is there a way for me to use a function similar to image(...) that will paste the image using a color value as the transparent portion?

i would much rather use a function that exists instead of writing my own. if i have to write my own, i will probably wind up going with transparent .gifs instead. Tongue

thanks in advance,
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hx // curse
 
fjen
Re: pasting transparent img
Reply #1 - Feb 22nd, 2007, 8:32am  
just save the alpha as a seperate greyscale-image and use:

http://processing.org/reference/PImage_mask_.html

F
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haliphax
Re: pasting transparent img
Reply #2 - Feb 22nd, 2007, 6:53pm  
so maybe the mask would fill all "transparent" pixels in white, the "opaque" pixels in black?

or vice versa?
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haliphax
Re: pasting transparent img
Reply #3 - Feb 22nd, 2007, 6:58pm  
wait.. i just had an epiphany (or something like it). i believe i should be able to load the color value of the upper-left-hand corner of the image i wish to paste (coord 0,0) and dynamically generate a mask for the image.

any color value of the original matching the transparent color value will be pasted to the mask as a "transparent" pixel. any other color value will be pasted to the mask as an "opaque" pixel.

i'm going to try that out when i get back from class this afternoon, and post my results.

thank you for pointing out this function! i knew there had to be something out there. Smiley
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davbol
Re: pasting transparent img
Reply #4 - Feb 22nd, 2007, 8:38pm  
You could use a PNG with alpha.
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fjen
Re: pasting transparent img
Reply #5 - Feb 22nd, 2007, 8:45pm  
haliphax wrote on Feb 22nd, 2007, 6:53pm:
so maybe the mask would fill all "transparent" pixels in white, the "opaque" pixels in black

or vice versa


right, have the mask-image be greyscale and do something like:

PImage img = loadImage("myImage.jpg");
PImage imgMask = loadImage("myImageMask.jpg");
img.mask(imgMask);

but then you might just as well rethink your dont-want-to-change-type policy and use PNG for all images as dave pointed out ... Smiley

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haliphax
Re: pasting transparent img
Reply #6 - Feb 23rd, 2007, 2:57am  
i think i can pull it off by generating a pixel array on-the-fly for the mask based on the first pixel of the image to be displayed.

thx for the help!
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hx // curse
 
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