[OSM-dev] speeding up tile rendering using a custom "convert -color 255" program.

SteveC steve at asklater.com
Thu Nov 23 11:08:09 GMT 2006


* @ 23/11/06 02:22:55 AM jburgess at uklinux.net wrote:
> While experimenting with the new tile renderer I noticed that the
> "convert -color 255" step of the tile generation was taking more CPU
> than anything else. To attempt to optimise this I hacked together a
> quick C program which uses the same ImageMagick library but with
> hardcoded options. For me this is several times faster than the stock
> convert command. 
> 
> I don't know the complete story behind why this custom version is so
> much faster. Perhaps it is because I've not provided any colour space
> correction or dithering parameters. Maybe i've lost some quality in the
> output, but the tiles I've generated with it so far look OK to me.

The important thing is the size, reducing the colour space reduces the
size of the tile. Are your things quicker _and_ smaller/same to the old
ones?

have fun,

SteveC steve at asklater.com http://www.asklater.com/steve/




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