QgsClipper Class Reference

A class to trim lines and polygons to within a rectangular region. More...

#include <qgsclipper.h>

Public Types
enum	Boundary { XMax, XMin, YMax, YMin }

Static Public Member Functions
static void	trimFeature (QVector< double > &x, QVector< double > &y, bool shapeOpen)
static void	trimPolygon (QPolygonF &pts, const QgsRectangle &clipRect)
static const unsigned char *	clippedLineWKB (const unsigned char *wkb, const QgsRectangle &clipExtent, QPolygonF &line)
	Reads a polyline from WKB and clips it to clipExtent.

Static Public Attributes
static const double	MAX_X = 16000
static const double	MIN_X = -16000
static const double	MAX_Y = 16000
static const double	MIN_Y = -16000

Detailed Description

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).

Member Enumeration Documentation

enum QgsClipper::Boundary

Enumerator:

XMax
XMin
YMax
YMin

Member Function Documentation

const unsigned char * QgsClipper::clippedLineWKB ( const unsigned char *  wkb, const QgsRectangle &  clipExtent, QPolygonF &  line  )

static

Reads a polyline from WKB and clips it to clipExtent.

Parameters

wkb	pointer to the start of the line wkb
clipExtent	clipping bounds
line	out: clipped line coordinates

void QgsClipper::trimFeature ( QVector< double > &  x, QVector< double > &  y, bool  shapeOpen  )

inlinestatic

void QgsClipper::trimPolygon ( QPolygonF &  pts, const QgsRectangle &  clipRect  )

inlinestatic

Member Data Documentation

const double QgsClipper::MAX_X = 16000

static

const double QgsClipper::MAX_Y = 16000

static

const double QgsClipper::MIN_X = -16000

static

const double QgsClipper::MIN_Y = -16000

static

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The documentation for this class was generated from the following files:

• /tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsclipper.h
• /tmp/buildd/qgis-2.6.0+wheezy1/src/core/qgsclipper.cpp