Base class for a spline interpolation. More...
#include <qwt_spline.h>
Public Member Functions | |
| virtual QVector< QLineF > | bezierControlLines (const QPolygonF &points) const =0 |
| Interpolate a curve with Bezier curves. | |
| virtual QPolygonF | equidistantPolygon (const QPolygonF &, double distance, bool withNodes) const |
| Find an interpolated polygon with "equidistant" points. | |
| virtual QPainterPath | painterPath (const QPolygonF &) const |
| Interpolate a curve with Bezier curves. | |
| virtual QPolygonF | polygon (const QPolygonF &, double tolerance) const |
| Interpolate a curve by a polygon. | |
| QwtSplineInterpolating () | |
| Constructor. | |
| virtual | ~QwtSplineInterpolating () |
| Destructor. | |
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 189 of file qwt_spline.h.
Constructor & Destructor Documentation
Constructor.
Definition at line 709 of file qwt_spline.cpp.
| QwtSplineInterpolating::~QwtSplineInterpolating | ( | ) | [virtual] |
Destructor.
Definition at line 714 of file qwt_spline.cpp.
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 QwtSplineC2, QwtSplineC1, QwtSplineLocal, QwtSplineCubic, and QwtSplinePleasing.
| 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 861 of file qwt_spline.cpp.
| QPainterPath QwtSplineInterpolating::painterPath | ( | const QPolygonF & | points | ) | const [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 QwtSplineC2, QwtSplineC1, QwtSplineLocal, QwtSplineCubic, and QwtSplinePleasing.
Definition at line 746 of file qwt_spline.cpp.
| QPolygonF QwtSplineInterpolating::polygon | ( | const QPolygonF & | points, |
| double | tolerance | ||
| ) | const [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 Bézier 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 803 of file qwt_spline.cpp.
The documentation for this class was generated from the following files: