Fit type of polyline

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A "Fit type" parameter determines how a polyline's curve fits to a polyline's vertices. In the examples below you see polylines with the same vertices coordinates but with different fit types.

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Fit type: LC_PLFIT_BULGE
Description: Direct lines or arcs between vertices.
Curve between vertices is defined by LC_PROP_VER_BULGE property, called "Bulge coefficient". It is calculated as CD/AD (see picture below), where A and B are consequtive vertices of a polyline. Value 0 (zero) means a linear segment. Negative coefficient means an arc's deviation to the left side, positive - to the right side, relative to AB direction.


Example: Polyline without bulges (parameter for all vertices = 0.0):


Bulge in vertex 0=-0.5, 1=-0.77, 4=0.2, others=0.0

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Fit type: LC_PLFIT_QUAD
Description: Quadratic B-spline.

Example:

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Fit type: LC_PLFIT_CUBIC
Description: Cubic B-spline.

Example:

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Fit type: LC_PLFIT_SPLINE
Description: Cubic spline goes through vertices. Spline direction at start point is controlled by the LC_PROP_PLINE_ANG0 and LC_PROP_PLINE_HASANG0 properties, direction at end point - by the LC_PROP_PLINE_ANG2 and LC_PROP_PLINE_HASANG2 properties.

Example:

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Fit type: LC_PLFIT_ROUND
Description: Polyline with rounded vertices.
The radius of vertex arc is defined by the LC_PROP_VER_RADIUS property.

Example: Vertices have the following parameters: 0=0.0, 1=3.0, 2=5.0, 3=5.0, 4=3.0, 5=10.0, 6=0.0

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Fit type: LC_PLFIT_LINQUAD
Description: Combination of linear segments and quadratic B-spline segments. These kinds of curves are used to code Windows TTF characters.
LC_PROP_VER_FIX property defines vertex behaviour: "False" means polyline goes offside of vertex, "True" means curve is fixed to vertex. Between offside vertices, LiteCAD generates spline segment.

Example: Vertices have the following parameters: 0=True, 1=False, 2=True, 3=True, 4=False, 5=False, 6=True


See Also

   lcBlockAddPolyline