nanogui: pixmaps and transparency for gif file
Subject:
pixmaps and transparency for gif file
From:
tj ####@####.####
Date:
14 Oct 2005 17:47:21 +0100
Message-Id: <434FE15F.2080708@comcast.net>
I am having a problem I cannot understand dealing with images, pixmaps
and transparency.
I have simple gif image, a black arrow on a white background, saved with
background transparent.
In my code I load it into an image.
Now, as an image I can use GrDrawImageToFit() to a window and the
transparency behaves as I expect. What ever is already on the window
shows through where the image's white background was.
But, if I first draw the image to a pixmap instead of a window and then
use GrCopyArea() the pixmap to the window, the background of the target
does not show through the transparent areas. Instead, the background of
the GR_ROOT_WINDOW shows through!!!! Not what is contained in the target
window.
My ultimate goal is to have my image icon in a pixmap, then xor text to
the pixmap so the text runs through the icon and then copy yhe pixmap to
window. Now the text is visible as one color
on either side of the incon and visible on the icon. Black text xor'ed
with Black icon = WHITE. And, since it was done in a pixmap, the text
outside the icon is black, not possibly multicolored do to xor'ing with
the original window.
But, my main question is why is the GR_ROOT_WINDOW showing through the
transparency of the pixmap instead of the target window?
tj
