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

Brent Fraser bfraser at geoanalytic.com
Tue Mar 26 12:58:59 PDT 2013

I'm not really clear how the label cache works, but how about:
     1. set LABELCACHE OFF for contour layers to label no matter what 
(could get ugly)
     2. set LABEL PRIORITY to max for contour layers (harsh for the 
other layers as they may get bumped)

And what about rendering Major and Minor contour interval lines 
differently (major=thick)?

Best Regards,
Brent Fraser

On 3/26/2013 1:04 PM, Daniel Morissette wrote:
> 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.

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