Porter-Duff composite is wrong when tiled option is true
Description
Environment
OS X Yosemite, Ubuntu 14.04
Attachments
Activity
Jukka Rahkonen November 30, 2017 at 11:58 AM
Thank you for a working advice on how to make the issue to appear.
I do not quite know what is the desired result but I can get polygons to show also in single tile mode if BBOX does not contain any roads.
Andrea Aime June 26, 2016 at 9:00 AM
Hi sorry I did not see your comment. If you want to look into it, you can put a breakpoint here and then follow up from there:
https://github.com/geotools/geotools/blob/master/modules/library/render/src/main/java/org/geotools/renderer/style/SLDStyleFactory.java#L1531
Sebastien Ouellet June 2, 2016 at 5:06 PM
It would at least be helpful to know where to look in the source code, as we could fix the issue with a few helpful tips if no regular developer can commit to resolve it.
Sebastien Ouellet June 2, 2016 at 4:54 PM(edited)
1 - Create a layer group with tasmania_states and tasmania_roads.
(order as seen in the screenshot)
2 - Edit the simple_road default style for tasmania_roads and add <VendorOption name="composite">destination-in</VendorOption> (file provided)
3 - Use the preview. You'll see at first that it looks as expected. Now change from Single-tile to Tiled and you'll see polygons in tiles where no roads are present.
Andrea Aime June 2, 2016 at 4:30 PM
Please provide step by step instructions to reproduce:
Small datasets (eventually the demo ones included in the release, if suitable)
Style(s)
Request
The duff-porter composite through the SLD VendorOption doesn't work well when a tiled WMS getMap call is requested. Single-tile works as expected.
We have two FeatureStyles that we composite with a destination-in operation to color linestrings only when they are intersecting a polygon, but if we zoom in sufficiently where no linestrings are present, parts of the polygons appear (cut in a way that follows tiling).
This seems to lead to a bug in the way the tiling works.
The two screenshots show the same area (at different zoom levels), and you see the polygons appear on each side of the linestrings.