[cairo] newbie question - fill pre-existing png polygons?
dagoldman at yahoo.com
Sun Aug 15 17:36:40 PDT 2010
> I use GD to make maps with labels and color fills. To add pdf output, I've
> using cairo / pango. The pdf is looking great so far.
> To make it easier to keep label placement consistent between png and pdf,
> I'm working on switching the png maps to also use cairo.
> With GD, I would import a png outline of the map that has been generated
> and use gdImageFill () to fill a polygon. With cairo, it's easy to get the
> outline map
> in with cairo_image_surface_create_from_png (). But I'm getting the feeling
> is not a helpful step under cairo, that cairo does not fill existing png
Are you asking for a 'Flood Fill' tool in cairo? If so, I think
there's none and it's not going to happen.
May be you can turn to use cairoscript backend to record your polygons
into a file. Then load them and fill the path using cairo_fill().
*********** Response below
Thanks. No, I'm not looking for flood fill. I have no idea how cairo fills. But
the cairo fill seems to work very well. I sometimes ran into problems with
gdImageFill () when it would reach a narrow "bottleneck" and crap out and not
fill the entire polygon.
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