[mapguide-trac] #1585: Zoom Rectange doesn't work properly in Ajax viewer

[MapGuide Open Source]

#1585: Zoom Rectange doesn't work properly in Ajax viewer
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   Reporter:  wuma         |       Owner:  Mars Wu
       Type:  defect       |      Status:  new    
   Priority:  low          |   Milestone:  2.2    
  Component:  AJAX Viewer  |     Version:  2.2.0  
   Severity:  trivial      |    Keywords:         
External_id:               |  
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Comment(by wuma):

 The reason is: in function ExecuteRectangleTool, the scale calculation and
 zoom is done this way:

 {{{
     if(tool == 3)
     {
         if((x2 - x1 <= 2) && (y2 - y1 <= 2))
             return;

         pt1 = ScreenToMapUnits(x1, y1);
         pt2 = ScreenToMapUnits(x2, y2);

         mcsW = pt2.X - pt1.X;
         mcsH = pt2.Y - pt1.Y;
         scale = CalculateScale1(mcsW, mcsH, mapDevW, mapDevH);
         scale = finscale? GetNearestFiniteScale(scale):
 NormalizeScale(scale);
         HideMapImage();
         GotoView(pt1.X + mcsW/2, pt1.Y + mcsH/2, scale, true, false);
     }
 }}}

 In screen space, coordinates increase from top-left corner to bottom-right
 corner, while in map CS space, the coordinates increase from bottom-left
 corner to top-right corner. As a result, mcsH will be a negative number.
 While in above function, it is used as a positive number. Then the
 calculated scale is wrong.

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Ticket URL: <http://trac.osgeo.org/mapguide/ticket/1585#comment:1>
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