Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!sunset.cis.ufl.edu!kml
From: kml@sunset.cis.ufl.edu (Kevin Lahey)
Newsgroups: comp.windows.x
Subject: XPutImage monochrome image to color screen
Summary: Why does it do strange things?
Message-ID: <20170@uflorida.cis.ufl.EDU>
Date: 25 Apr 89 17:27:10 GMT
Sender: news@uflorida.cis.ufl.EDU
Reply-To: kml@mosquito.cis.ufl.edu (Kevin Lahey)
Organization: UF Center for Computer Vision Research
Lines: 31

XPutImage appears to do some strange things when attempting to 
display monochrome images of the XYBitmap format on a display of 
depth greater than one.

I'm running X11R3 with the Purdue speedups on various Sun3s running SunOS 4.0.
I'm using twm, and trying to use the Athena widgets and the toolkit.

I create a core widget inside a viewport widget.  I set up to get Expose
events.  When I increase the size of the window or scroll it using the
scroll bars, I get the expose event, which is the correct size,
and I call XPutImage with the x, y, width and height values from the event.
The image gets updated correctly, then a vertical white band is drawn on the
image, generally near the edges of the image which have just been re-drawn.
This only happens on the color screens; the program works perfectly
on screens of depth one.  It also works fine when I am refreshing the entire
image;  for instance, if I iconify the window, then de-iconify it, the
image looks fine.  It only screws up when it is trying to update only a part
of the image.

I have a work-around -- namely, I create a pixmap, XPutImage to the
pixmap, and then do an XCopyPlane to the window.  However, this doesn't
strike me as elegant or clever;  I should like to be able to use XPutImage
to write to either color or monochrome screens.

Thanks,
Kevin
--
Kevin Lahey                  UUCP: ...gatech!uflorida!beach.cis.ufl.edu!kml
University of Florida, CIS   Internet: kml@beach.cis.ufl.edu
Whenever you find that you are on the side of the majority,
it is time to reform.  -- Mark Twain