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From: dsr@mir.mitre.org (Douglas S. Rand)
Newsgroups: comp.windows.x
Subject: Re: Draw color image
Message-ID: <1991Feb4.172202.27154@linus.mitre.org>
Date: 4 Feb 91 17:22:02 GMT
References: <1991Feb2.000128.5464@efi.com>
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Reply-To: dsr@mir.mitre.org (Douglas S. Rand)
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In article <1991Feb2.000128.5464@efi.com>, chiu@efi.com (Chan Chiu) writes:
> I am programming to display color image in X window (256 colors).
> 
> It looks like XDrawPointer doesn't support color (It doesn't have a parameter
> to input color value).
> 

Wrong.  The GC in XDrawPoint or XDrawPoints allows you to specify the foreground
color.  However this is an inefficient way to deal with images.

> I am aware of only two ways : (Correct me if I'm wrong)
> 
> 1, I use pixmap. Then I use XCopyArea. 
>    The trick here is that I cannot find any routine to modifies pixmap
>    data.

You can use pixmaps to buffer the image.  All the XDraw** routines take a 
drawable which is defined as either a window or a pixmap.  So...

> 2, I use XImage. Then XPutImage to window.
> 
Use XPutImage to put the image to a pixmap and make that pixmap the 
background pixmap of your display window.  Works great.  

> Any pointers ?
> 
> /Chan

O'Reilly books vI and vII have it all.  There are doubtlessly other
places as well.

-- 
Douglas S. Rand 
Internet:   <dsrand@mitre.org>
Snail:	    MITRE, Burlington Road, Bedford, MA 
Disclaimer: MITRE might agree with me - then again...
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