HATCH outside of polygon with 8 bit #4512

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rgreenwood opened this Issue Oct 25, 2012 · 2 comments

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@rgreenwood

The HATCH fill pattern extends beyond polygon boundaries in seemingly random directions. Depending on zoom and window size the "extra" hatching will appear in different areas. The problem occurs with 8 bit PC256 output but not RGB output formats, e.g. GIF but not PNG using default 6.03 outputformat options. The issue does not occur in MapServer 5.6. An example map file and shapefile are here:
http://www.greenwoodmap.com/hatch_bug.zip
Using the above files the following URL will illustrate the issue:
http://localhost/cgi-bin/mapserv?map=/temp/hatch_bug/hatch_bug.map&map_imagetype=gif&mode=map&mapext=1435458+1718624+1511913+1757913&map_size=792+407

And switching map_imagetype above to png will eliminate the problem.

Thanks,
Rich

@tbonfort
Member

Was able to reproduce, this is probably due to the GD coordinate transformer that is allowed to create degenerate polygons (i.e. a polygon with a single vertice is considered to be a single pixel) which don't play nicely with the clipper used to clip hatch lines.

@tbonfort tbonfort added a commit to tbonfort/mapserver that referenced this issue Aug 6, 2013
@tbonfort tbonfort refactor SDE detection in cmake files (#4512,#4700)
- add a specific plugin configuration
- checks for sde,sg and pe libs, adds pthread,socketi and dl if found
- adds #define SDE64 on 64 bit platforms
b677cf3
@tbonfort
Member

WONTFIXing this one as we're dropping support for GD entirely.

@tbonfort tbonfort closed this Aug 20, 2013
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