msClipPolygonRect() / msClipPolylineRect()

[Steve Lime]

Correct. Filtering based purely on bboxes is done very early in the
process. msLayerWhichShapes (in the case of shapefiles) sets up a bit
array (ideally from a quadtree index) of shapes *in* the rendering
window and processing (via msLayerNextShape) list limited to those
shapes.

>>> Daniel Morissette <dmorissette at DMSOLUTIONS.CA> 3/24/2005 12:44:02
PM >>>
Frank Warmerdam wrote:
>
> Looking at this code, I can't help but wonder if we couldn't avoid
reading
> all the geometry for shapes that are ourside our current rendering
window
> if we did slightly closer integration between the mapshape.c shape
reading
> code and the higher level layer logic for shapes.   However, this is
outside
> the scope of my current optimization efforts focused on S-57 input.
>

I think the prefiltering based on map extents that you suggest is
already done by msLayerWhichShapes(), prior to reading shapes from the
file. Steve should be able to comment on that.

Daniel
--
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  Daniel Morissette               dmorissette at dmsolutions.ca
  DM Solutions Group              http://www.dmsolutions.ca/
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