[Xastir] Linear scaling for OSM - ANNOUNCEMENT

[Jerry Dunmire]

The CVS archive has been updated to include code that will scale the
OSM bitmap images. This restores the default linear scaling used by
Xastir and 'fixes' the area zoom (no changes to area zoom were needed
and that part of the code has not been changed).

Support for binned zoom levels remains. The scaling mode is selected
by choosing map files with .geo (linear) or .osm (OSM binned zoom
levels) extensions.

I have also added support for additional OSM map styles and provided
.geo/.osm files for the styles I know of. For an example of the styles
try this URL:

http://ojw.dev.openstreetmap.org/StaticMap/?lat=37.3464045507&lon=-121.942749023&z=13&mode=Style&

mapnick is the default OpenStreetMap style
osmarendar is the default Tiles at Home style
cloudmade* styles are from Cloudmade: http://www.cloudmade.com

Known issues:
  - Area zooms do not work well for binned OSM levels (.osm files)
    This could probably be fixed, but for now I am making it a low priority.

  - Text and lines on OSM maps will be aliased (blocky, blurred,
missing bits, jagged, ...) to one degree or another for most linear
zoom levels. The artifacts will be minimized with the linear zoom
level is closest to the OSM level.
    It may be possible to improve the scaling and reduce the artifacts.

Future plans:
I am going to shift my work a bit and try to make direct use of the
OSM tiled images. This should improve caching, allow off line
operation, and provide flexibility for choosing tile servers and/or
using custom tiles.

I expect that the change to tiled images will take me a while. In the
mean time I hope you enjoy the static image OSM version.

73,
...jerry
KA6HLD