[cairo] Crash with very large image surface

[Laszlo Pandy]

On Tuesday 23 May 2006 7:29 am, Alexander Larsson wrote:
> Why do you have to allocate such a large cairo image? You never need a
> larger one than the width of the app window. Why don't you just allocate
> one of that width and set the cairo matrix to shift it to the current
> position.

How can we use a matrix so shift the image surface? We want to keep the 
waveform cached so we don't have to redraw it all the time. Is there any way 
we can show only part of the cached image without using 
cairo_set_source_surface() and cairo_paint() , which causes a crash?