Hello,

a long time ago, Leonardo Alejandro Bustos Wallace wrote:

I work whith grx20 in DOS, and I create an image using Context and bitmap: GrImageBuild (2 ways, seperately). I don't know how put the image with the background of the image (black) without deleting the previous image. I think that's the problem itsn't big, but I try in all the ways.

I do not exactly understand your problem. Maybe you have an image with black background and you want to put all non-black parts to the current context (screen)?

There are probably better solutions, but the following should work: Let's call the picture you want to put on the screen "map". First, generate a bitmap "mask" with white pixels everywhere where "map" has black ones (which are intended to be transparent), and black pixels where "map" has the actual picture. Second, AND the screen with "mask", thus leaving a block hole of the shape of the picture in "map". Third, OR "map" onto the screen - voilà.

Hope this helps,

Peter