toFloat hell

[erilem]

As now known toFloat represents a pretty high percentage of execution time when panning the map.

toFloat is used in two classes only: LonLat and Bounds. In LonLat it's used in the constructor, and in add. In Bounds it's used in the constructor, and in contains.

FireBug's profile tool reports that toFloat represents ~10% of execution time when panning the map.

I did some experiments, removing toFloat calls and doing profiles. The results:

• when removing toFloat from LonLat:init then toFloat == ~7%
• when also removing toFloat from LonLat:add then toFloat == ~7% (no effect)
• when also removing toFloat from the Bounds:init then toFloat == ~2%
• and when also removing toFloat Bounds:contains method then toFloat == 0%

This suggests that we'd better not call toFloat from LonLat and Bounds, and make LonLat and Bounds users responsible for providing floats.

[pgiraud]

See #2875.