Image surface problem when showing portion of artwork?

[Ray at Daylon]

Sorry, my bad. My renderer was doing knockout fills as part of rendering 
only the outer portion of strokes and was doing unnecessary extra work 
which when left out, renders the paths correctly.

The other problems with stroked paths still remain; afaik it looks like 
a stroke is terminated too early when it meets a clip boundary (in this 
case the edge of the image surface).

Ray



On 9/1/2024 2:18 PM, Ray at Daylon wrote:
> Hi everyone,
> 
> There seems to be a rendering issue in Cairo 1.18.0 where drawing paths 
> in an image surface that shows only a subset of the artwork causes some 
> paths to fill incorrectly.
> 
> The attached file tiger_okay.jpg shows a portion of the standard Tiger 
> image rendered on a 512 x 512 px image surface, and everything's fine.
> 
> The file tiger_error.jpg, however, is a closer zoom also 512 x 512 px in 
> size but the dark orange paths below and to the left of the eye cover 
> more area than normal.
> 
> No clipping is done either by the app or by telling Cairo to set a clip 
> rectangle; an image surface is created and all the paths are drawn. I 
> imagine there is a default clip rectangle matching the surface extent 
> that Cairo initially defines.
> 
> There are other problems with stroked paths in other areas at closer 
> zooms, but I'll treat that as a separate issue.
> 
> Ray Gardener
> Daylon Graphics Ltd.