[mapserver-dev] Request for review/comments on RFC 85 (Contour Layer Rendering)

Daniel Morissette dmorissette at mapgears.com
Tue Mar 26 12:04:49 PDT 2013

On 13-03-26 2:54 PM, Brent Fraser wrote:
> Hmmm.   How about:
>       - All other layers are to be ignored (rendered normally)
>      - generate (but don't yet render) the contour lines
>      - generate the labels (consider the labelcache?) using the contour
> lines, compute the label bounding boxes
>      - clip the contour lines to the bounding boxes, render the
> remaining line segments
>      - render the labels

This example is assuming that there are no labels in any of the layers 
that follow the contour layer in the rendering.

Unfortunately it's not that simple: the labelcache is Last-in First-out, 
so if you have labels in the layers that follow the contour layer they 
need to be considered as well and take precedence over the contour 
labels in the labelcache processing. Hence the comment in my last mail 
about requiring multiple passes on the data.

Daniel Morissette
Provider of Professional MapServer Support since 2000

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