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From: etaylor@wilkins.iaims.bcm.tmc.edu (Eric Taylor)
Newsgroups: comp.windows.x
Subject: Re:
Message-ID: <3099@gazette.bcm.tmc.edu>
Date: 6 Dec 90 18:38:04 GMT
References: <9012061432.AA08997@expo.lcs.mit.edu>
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Reply-To: etaylor@wilkins.iaims.bcm.tmc.edu (Eric Taylor)
Organization: Baylor College of Medicine, Houston, Tx
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In article <9012061432.AA08997@expo.lcs.mit.edu>, PATERNO@ICNUCEVM.CNUCE.CNR.IT writes:
|> The Xlib - C Language X Interface states that the function
|> XCreateImage "allocates the memory needed for an XImage structure"....
|> ..."but doesn't allocate space for the image itself."
|> How can we determine the amount of space to be allocated for image
|> data in the various formats (XY* or Z*)?
|> i.e. if I have to display an image in a say 600x600 pixels window
|> how many bytes I need to allocate?

When you create the image, use NULL for the data argument.
After it is created fill in data field with:
	image->data = malloc(image->height * image->bytes_per_line) ;

I believe that this is the easiest and safest method.

It was unfortunate that X did not provide a function that allocated the data
for you.
--
					Eric Taylor
					Baylor College of Medicine
					etaylor@wilkins.bcm.tmc.edu
					(713) 798-3776