evgabb@sdrc.UUCP (Rob Gabbard) (05/28/90)
I've noticed some strange behavior on my Turbo SRX when running X in combined mode with the following X0screens configuration: /dev/o4crt /dev/crt depth 16 depth 24 doublebuffer Some times when this comes up I have a default colormap of 16 colors (expected) and other times I get one that has 15 entries (?). I thought maybe one was saved for the transparent color but when I run xseethru it can't get a transparent color so that's not it. Anybody know why this occurs ? -- Rob Gabbard (uunet!sdrc!evgabb) Technical Development Engineer Structural Dynamics Research Corp
kam@hpcvlx.cv.hp.com (Keith Marchington) (05/30/90)
> I've noticed some strange behavior on my Turbo SRX when running X in combined > mode with the following X0screens configuration: > /dev/o4crt /dev/crt depth 16 depth 24 doublebuffer > Some times when this comes up I have a default colormap of 16 colors (expected) > and other times I get one that has 15 entries (?). I thought maybe one was > saved for the transparent color but when I run xseethru it can't get a > transparent color so that's not it. > Anybody know why this occurs ? > Rob Gabbard (uunet!sdrc!evgabb) Well, you will get 16 colors in OVERLAY mode, and 15 colors in COMBINED mode, but I think it would be well nigh impossible to get 16 in COMBINED mode. Now for the reason. In combined mode, we treat both sets of planes (both image and overlay) as a single screen. The overlay planes are the default visual type and is where the root window is painted. To see the image planes, the overlays must be made transparent. So we allocate the colormap so that the client can use the first fifteen, and we keep the sixteenth to assure ourselves that we will have a pixel value that we can paint that will be transparent. Keith Marchington HP Corvallis, Oregon