[mapguide-trac] #436: Stylization: Modify rotation calculation to use atan

[MapGuide Open Source]

#436: Stylization: Modify rotation calculation to use atan
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 Reporter:  louisewatson       |         Owner:  louisewatson
     Type:  defect             |        Status:  closed      
 Priority:  medium             |     Milestone:  2.1         
Component:  Rendering Service  |       Version:  2.0.0       
 Severity:  major              |    Resolution:  fixed       
 Keywords:                     |   External_id:  1041451     
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Changes (by louisewatson):

  * status:  assigned => closed
  * resolution:  => fixed

Comment:

 This problem was due to the fact that atan2 was being used to calculate
 the rotation of the line labels based on the slope of the line.  Atan2
 takes two parameters, dx and dy, and considers the sign of each to return
 values in any of the 4 quadrants.

 The fix was to calculate the slope as dy/dx and pass to atan. Atan only
 returns values in the first two quadrants.

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Ticket URL: <http://trac.osgeo.org/mapguide/ticket/436#comment:2>
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