[cairo] Blitting and sprites in Cairo
chris at chris-wilson.co.uk
Wed May 15 02:07:17 PDT 2013
On Wed, May 15, 2013 at 10:47:31AM +0200, Donn wrote:
> How would you move a sprite across a background?
> The sprite could be:
> draw rectangle 32x32
> draw sprite with cairo functions
> But now:
> Draw background once
> loop start
> Copy rect of bg where sprite is gonna go //How do you do this?
> translate() //move sprite
> paint() //Draw the sprite
> //Replace the backdrop
> ?? //Some kind of set_source + paint again?
> That kind of jazz.
Assuming you've disposed off the background layer and only have the
frontbuffer left - yes, you would need to make a copy of the area to be
damaged (after undoing the old sprite and before applying the new).
However, since you will want to double-buffer the expose event at least,
you can use that as a composition step and not burn the sprites into the
Chris Wilson, Intel Open Source Technology Centre
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