[Sdl4fp-users] blitting outside screen area

[Matthias <ma...@gm...>]

Hi there.

I have strange behaviour if I blit outside screen area. I used =
SDL_SETCLIPRECT to define the clipping area (the error described next =
occurs if I don't define clip area, too). The clip area is exactly the =
screen area (it returns TRUE).=20

I noticed that if I clipped an image outside the area and later try to =
blit it to the visible area the image won't be seen.=20

Next I tried to clip an image (200 x 200) at a position (for example =
x=3D 200, y=3D -100) so it would be partially in visible area and other =
part outside screen area. Then, as expected, the partial part inside =
screen area is shown. - But if I try to clip it to another part of the =
screen, so the whole image should be seen, only the partial part is =
seen.=20

Most curious thing about this: I blitted the image, after the clipping =
half outside the screen as described before, at position (0,0)... =
instead of an [200 x 200]-Image with the first part (200 x 100) cleared =
I just got the shown part at (0,0) so it seems as if the image got cut =
or shrinked by half. But if I check the value of width and height of =
image it stayed 200 x 200. I am really not sure how to explain this.=20

Any hints how to let images be blitable after blitting them to outside =
area? What is the reason why it does not work as described?

Thanks a lot!

Greets,
Matthias