QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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A class to trim lines and polygons to within a rectangular region. More...
#include <qgsclipper.h>
Public Types | |
enum | Boundary { XMax , XMin , YMax , YMin , ZMax , ZMin } |
A handy way to refer to the four boundaries. More... | |
Static Public Member Functions | |
static bool | clipLineSegment (double left, double right, double bottom, double top, double &x0, double &y0, double &x1, double &y1) |
Clips a line segment to a rectangle. | |
static void | clipped3dLine (const QVector< double > &xIn, const QVector< double > &yIn, const QVector< double > &zIn, QVector< double > &x, QVector< double > &y, QVector< double > &z, const QgsBox3D &clipExtent) |
Takes a line with 3D coordinates and clips it to clipExtent. | |
static QPolygonF | clippedLine (const QgsCurve &curve, const QgsRectangle &clipExtent) |
Takes a linestring and clips it to clipExtent. | |
static QPolygonF | clippedLine (const QPolygonF &curve, const QgsRectangle &clipExtent) |
Takes a 2D curve and clips it to clipExtent. | |
static void | trimFeature (QVector< double > &x, QVector< double > &y, bool shapeOpen) |
Trims the given feature to a rectangular box. | |
static void | trimPolygon (QPolygonF &pts, const QgsRectangle &clipRect) |
Trims the given polygon to a rectangular box, by modifying the given polygon in place. | |
static void | trimPolygon (QVector< double > &x, QVector< double > &y, QVector< double > &z, const QgsBox3D &clipRect) |
Trims a polygon consisting of the specified x, y and z values to a pseudo 3D box, by modifying the arrays in place. | |
Static Public Attributes | |
static const double | MAX_X = 16000 |
Maximum X-coordinate of the rectangular box used for clipping. | |
static const double | MAX_Y = 16000 |
Maximum Y-coordinate of the rectangular box used for clipping. | |
static const double | MIN_X = -16000 |
Minimum X-coordinate of the rectangular box used for clipping. | |
static const double | MIN_Y = -16000 |
Minimum Y-coordinate of the rectangular box used for clipping. | |
A class to trim lines and polygons to within a rectangular region.
The functions in this class are likely to be called from within a render loop and hence need to as CPU efficient as possible. The main purpose of the functions in this class are to trim lines and polygons to lie within a rectangular region. This is necessary for drawing items to an X11 display which have a limit on the magnitude of the screen coordinates (+/- 32768, i.e. 16 bit integer).
Definition at line 50 of file qgsclipper.h.
enum QgsClipper::Boundary |
A handy way to refer to the four boundaries.
Enumerator | |
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XMax | |
XMin | |
YMax | |
YMin | |
ZMax | Maximum Z.
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ZMin | Minimum Z.
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Definition at line 82 of file qgsclipper.h.
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inlinestatic |
Clips a line segment to a rectangle.
An implementation of the 'Fast clipping' algorithm (Sobkow et al. 1987, Computers & Graphics Vol.11, 4, p.459-467).
left | x-coordinate of left side of rectangle |
right | x-coordinate of right side of rectangle |
bottom | y-coordinate of bottom side of rectangle |
top | y-coordinate of top side of rectangle |
x0 | x-coordinate of start of line |
y0 | y-coordinate of start of line |
x1 | x-coordinate of end of line |
y1 | y-coordinate of end of line |
true
if line was clipped.Definition at line 776 of file qgsclipper.h.
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Takes a line with 3D coordinates and clips it to clipExtent.
Definition at line 40 of file qgsclipper.cpp.
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Takes a linestring and clips it to clipExtent.
curve | the linestring |
clipExtent | clipping bounds |
Definition at line 110 of file qgsclipper.cpp.
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Takes a 2D curve and clips it to clipExtent.
curve | the linestring |
clipExtent | clipping bounds |
Definition at line 115 of file qgsclipper.cpp.
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inlinestatic |
Trims the given feature to a rectangular box.
Returns the trimmed feature in x and y. The shapeOpen parameter determines whether the function treats the points as a closed shape (polygon), or as an open shape (linestring).
Definition at line 260 of file qgsclipper.h.
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inlinestatic |
Trims the given polygon to a rectangular box, by modifying the given polygon in place.
pts | polygon as 2D coordinates |
clipRect | clipping rectangle |
Definition at line 281 of file qgsclipper.h.
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inlinestatic |
Trims a polygon consisting of the specified x, y and z values to a pseudo 3D box, by modifying the arrays in place.
Definition at line 295 of file qgsclipper.h.
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Maximum X-coordinate of the rectangular box used for clipping.
Definition at line 72 of file qgsclipper.h.
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Maximum Y-coordinate of the rectangular box used for clipping.
Definition at line 76 of file qgsclipper.h.
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Minimum X-coordinate of the rectangular box used for clipping.
Definition at line 74 of file qgsclipper.h.
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Minimum Y-coordinate of the rectangular box used for clipping.
Definition at line 78 of file qgsclipper.h.