QwtSplineInterpolating(3) Qwt User's Guide QwtSplineInterpolating(3)
NAME
QwtSplineInterpolating - Base class for a spline interpolation.
SYNOPSIS
#include
Inherits QwtSpline.
Inherited by QwtSplineG1.
Public Member Functions
QwtSplineInterpolating ()
Constructor.
virtual ~QwtSplineInterpolating ()
Destructor.
virtual QPolygonF equidistantPolygon (const QPolygonF &, double
distance, bool withNodes) const
Find an interpolated polygon with 'equidistant' points.
virtual QPolygonF polygon (const QPolygonF &, double tolerance) const
override
Interpolate a curve by a polygon.
virtual QPainterPath painterPath (const QPolygonF &) const override
Interpolate a curve with Bezier curves.
virtual QVector< QLineF > bezierControlLines (const QPolygonF &) const
=0
Interpolate a curve with Bezier curves.
Additional Inherited Members
Detailed Description
Base class for a spline interpolation.
Spline interpolation is the process of interpolating a set of points
piecewise with polynomials. The initial set of points is preserved.
Definition at line 193 of file qwt_spline.h.
Member Function Documentation
QVector< QLineF > QwtSplineInterpolating::bezierControlLines (const
QPolygonF & points) const [pure virtual]
Interpolate a curve with Bezier curves. Interpolates a polygon
piecewise with cubic Bezier curves and returns the 2 control points of
each curve as QLineF.
Parameters
points Control points
Returns
Control points of the interpolating Bezier curves
Implemented in QwtSplineCubic, QwtSplinePleasing, QwtSplineLocal,
QwtSplineC2, and QwtSplineC1.
QPolygonF QwtSplineInterpolating::equidistantPolygon (const QPolygonF &
points, double distance, bool withNodes) const [virtual]
Find an interpolated polygon with 'equidistant' points. When withNodes
is disabled all points of the resulting polygon will be equidistant
according to the parametrization.
When withNodes is enabled the resulting polygon will also include the
control points and the interpolated points are always aligned to the
control point before ( points[i] + i * distance ).
The implementation calculates bezier curves first and calculates the
interpolated points in a second run.
Parameters
points Control nodes of the spline
distance Distance between 2 points according to the parametrization
withNodes When true, also add the control nodes ( even if not being
equidistant )
Returns
Interpolating polygon
See also
bezierControlLines()
Reimplemented in QwtSplineC2, and QwtSplineC1.
Definition at line 863 of file qwt_spline.cpp.
QPainterPath QwtSplineInterpolating::painterPath (const QPolygonF & points)
const [override], [virtual]
Interpolate a curve with Bezier curves. Interpolates a polygon
piecewise with cubic Bezier curves and returns them as QPainterPath.
The implementation calculates the Bezier control lines first and
converts them into painter path elements in an additional loop.
Parameters
points Control points
Returns
Painter path, that can be rendered by QPainter
Note
Derived spline classes might overload painterPath() to avoid the
extra loops for converting results into a QPainterPath
See also
bezierControlLines()
Implements QwtSpline.
Reimplemented in QwtSplinePleasing, QwtSplineLocal, QwtSplineCubic,
QwtSplineC2, and QwtSplineC1.
Definition at line 748 of file qwt_spline.cpp.
QPolygonF QwtSplineInterpolating::polygon (const QPolygonF & points, double
tolerance) const [override], [virtual]
Interpolate a curve by a polygon. Interpolates a polygon piecewise with
Bezier curves approximating them by polygons.
The approximation is based on 'Piecewise Linear Approximation of Bezier
Curves' by Roger Willcocks ( http://www.rops.org )
Parameters
points Control points
tolerance Maximum for the accepted error of the approximation
Returns
polygon approximating the interpolating polynomials
See also
bezierControlLines(), QwtSplineBezier::toPolygon()
Reimplemented from QwtSpline.
Definition at line 805 of file qwt_spline.cpp.
Author
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Version 6.2.0 Sun Jul 18 2021 QwtSplineInterpolating(3)