ability to use alternative renderers

[assefa]

The first case would be able to use an agg renderer for raster layers in the kml driver.

[assefa]

As discussed off list, we could use a processing tag to use an alternative renderer. We could do that in mapdraw.c possible. Attached patch was tested with kml driver. Is this approach ok or another one needed?

[tbonfort]

Assefa,

The approach you are taking seems correct to me, although I have not tested this. It should be noted however that in the patch you attached, the opacity of the requested layer won't be honored.

[assefa]

Regarding opacity, I was not sure how it was working. In the case I am using it now, I set the opacity in the kml docuement (the groundoverlay color that contains the refernece to the png file). You are right the png file by itself does not honor the opacity, but the resulting kml layer is transparent.

Id the transparency done when the mergeRasterBuffer process?

[tbonfort]

There are two problems with the current behavior:

• potential problem with symbolset that can contain cached versions of the symbol, see #3834
• the first msSelectOutputFormat updates the map outputformat. it should be set back to what was used once the layer is finished.

[tbonfort]

my bad, msSelectOutputFormat does not update the map outputformat, but it does change the map image type.

both issues fixed in r11558