[thuban-Patches][670] Clipping the points avoids wx's scale limitations

[thuban-patches@wald.intevation.org]

Patches item #670, was opened at 2008-07-10 11:35
Status: Open
Priority: 3
Submitted By: Anthony Lenton (elachuni)
Assigned to: Nobody (None)
Summary: Clipping the points avoids wx's scale limitations 
Version: None
Category: None


Initial Comment:
Attached is a patch that allows you to lift the max_scale limit, by clipping points within wx's limits before drawing.

 * Optimized renderers are disabled in the patch as clipping is only implemented in the Python default renderers.  As clipping is done after projecting the points, if the idea seems sound we'd have to implement clipping in the C wxproj renderers too, or pass the points back to Python to be clipped after projecting.

 * in Thuban.UI.viewport.ViewPort's calc_min_max_scales, max_scale is now set arbitrarily to 500000.  We can instead choose a different maximum scale policy, as now we're not restricted by wx's limitations.

 * I've added quite a bit of testing but quite likely a couple of cases are still not handled correctly.  Failing test cases are welcome. 

 * I haven't tried clipping with ExportRenderer or PrinterRenderer, I don't know if those will be trouble.

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