display lib: support for curveto
|Reported by:||hamish||Owned by:|
it would be nice if the display library had a D_curve_abs() and D_curve_rel() functions to handle Bezier Curves. Among other things this would make displaying EPS/SVG/DXF graphics directly on the display monitor/canvas/whatever you want to call it now a whole lot easier. I am not sure if it is better to expose a variable to control the number of vertices along the line to be produced, or for the display lib to decide that dynamically. I assume the coord input needs would be 3 or more pairs of coords. Again, not sure if either be like D_polyline_*() and require a "int n" argument or just have it loop while coord != NULL.
In the short term it could immediately be added to d.graph as a new
curve instruction and as a demonstration/testbed. (See the LIMITATIONS section of the d.graph man page)
I expect the cairodriver and psdriver could use it directly, but not sure of GIS uses for it beyond decorations. Hmmm... new line drawing tool in wxVdigit?
thanks, Hamish (who has just spent more time than I care to calculating vertices by hand)