[ka-Map-dev] [Bug 1457] New: [ka-Map] tile source redraw optimizations

bugzilla-daemon at bugzilla.maptools.org bugzilla-daemon at bugzilla.maptools.org
Tue May 9 10:27:25 EDT 2006


           Summary: [ka-Map] tile source redraw optimizations
           Product: ka-Map
           Version: 0.2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: core
        AssignedTo: ka-map-dev at lists.maptools.org
        ReportedBy: pspencer at dmsolutions.ca

when using tile_source redraw, tile.php re-renders the meta-tile for every tile
request, causing huge server load and very poor performance.  I will enhance it
to include a timestamp feature that allows the server to cache the tiles at
least temporarily to avoid this problem.

In addition, I will add the capability to have a layer automatically refresh
itself in the client on a specific interval.

Proposed changes are:

1) add new metadata to layer for "redraw_interval".  This is the amount of time
(in seconds) after a meta-tile is rendered that the tile is considered
'current'.  kaMap clients passing a timestamp newer than the metatile timestamp
plus the interval will cause the metatile (and tiles) to be re-rendered.

2) add new metadata to layer for "refresh_interval".  This is the interval at
which to refresh a layer's tiles in the client

3) modify init.php to pass both redraw_interval and refresh_interval to the
client when creating layers

4) modify tile.php to check for an incoming timestamp and force tile rendering
if necessary.  Also create a timestamp in the meta directories when creating tiles.

5) modify _layer in kaMap.js to pass layer-wide timestamp if tile_source is set
to redraw.

6) modify _layer in kaMap.js to add a redraw method that resets the timestamp
for a layer.  The redraw method can be called manually or automatically at some
interval.  Passing an argument to redraw will set the redraw interval to the
specified value (in seconds) or remove it if <=0 is passed.

7) modify _layer in kaMap.js to trigger redrawing of a layer on an interval if
refresh_interval is passed to the constructor.

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