[mcclim-ticket] #6: gtkairo: cairo medium ellipse drawing and line styles

[mcclim]

#6: gtkairo: cairo medium ellipse drawing and line styles
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 Reporter:  dlichteblau  |       Owner:  somebody
     Type:  defect       |      Status:  new     
 Priority:  major        |   Milestone:          
Component:  component1   |     Version:          
 Keywords:               |  
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 Gtkairo Bug 22:

    The cairo version of medium-draw-ellipse* needs a rewrite.

 (The gdk medium can draw ellipses just fine, however.)

 The current implementation fills an ellipse, but completely fails when
 drawing its border:

 {{{
   ;; This one is tricky. Cairo doesn't know ellipses, it only knows
   ;; circles. But then it is fully capable to draw circles under affine
   ;; transformations only that the line style is transformed too. So
   ;; what we do: We setup an [additional] transformation to from our
   ;; ellipse to a circle and setup line style properly transformed. ---
   ;; This is not entirely correct in case of shearing or odd scaling
   ;; transformations.
 }}}

 Unless cairo starts supporting ellipses natively, I would suggest using
 bezier curves to approximate an ellipse.

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Ticket URL: <http://trac.common-lisp.net/mcclim/ticket/6>
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