Implementation of GeometrySimplifier using the "MapToPixel" algorithm. More...

#include <qgsmaptopixelgeometrysimplifier.h>

Inheritance diagram for QgsMapToPixelSimplifier:

Public Types
enum	SimplifyAlgorithm { Distance = 0 , SnapToGrid = 1 , Visvalingam = 2 , SnappedToGridGlobal = 3 }
	Types of simplification algorithms that can be used. More...

enum	SimplifyFlag { NoFlags = 0 , SimplifyGeometry = 1 , SimplifyEnvelope = 2 }
	Applicable simplification flags. More...

Public Member Functions
	QgsMapToPixelSimplifier (int simplifyFlags, double tolerance, SimplifyAlgorithm simplifyAlgorithm=Distance)
	Constructor.

bool	isGeneralizableByMapBoundingBox (const QgsRectangle &envelope) const
	Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context.

void	setSimplifyAlgorithm (SimplifyAlgorithm simplifyAlgorithm)
	Sets the local simplification algorithm of the vector layer managed.

void	setSimplifyFlags (int simplifyFlags)
	Sets the simplification hints of the vector layer managed.

void	setTolerance (double value)
	Sets the tolerance of the vector layer managed.

QgsAbstractGeometry *	simplify (const QgsAbstractGeometry *geometry) const override
	Returns a simplified version the specified geometry.

QgsGeometry	simplify (const QgsGeometry &geometry) const override
	Returns a simplified version the specified geometry.

SimplifyAlgorithm	simplifyAlgorithm () const
	Gets the local simplification algorithm of the vector layer managed.

int	simplifyFlags () const
	Gets the simplification hints of the vector layer managed.

Public Member Functions inherited from QgsAbstractGeometrySimplifier
virtual	~QgsAbstractGeometrySimplifier ()=default

Static Public Member Functions
static bool	isGeneralizableByMapBoundingBox (const QgsRectangle &envelope, double map2pixelTol)
	Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context.

Static Public Member Functions inherited from QgsAbstractGeometrySimplifier
static bool	isGeneralizableByDeviceBoundingBox (const QgsRectangle &envelope, float mapToPixelTol=1.0f)
	Returns whether the device-envelope can be replaced by its BBOX when is applied the specified tolerance.

static bool	isGeneralizableByDeviceBoundingBox (const QVector< QPointF > &points, float mapToPixelTol=1.0f)
	Returns whether the device-geometry can be replaced by its BBOX when is applied the specified tolerance.

Static Protected Member Functions
static float	calculateLengthSquared2D (double x1, double y1, double x2, double y2)
	Returns the squared 2D-distance of the vector defined by the two points specified.

static bool	equalSnapToGrid (double x1, double y1, double x2, double y2, double gridOriginX, double gridOriginY, float gridInverseSizeXY)
	Returns whether the points belong to the same grid.

Protected Attributes
SimplifyAlgorithm	mSimplifyAlgorithm
	Current algorithm.

int	mSimplifyFlags
	Current simplification flags.

double	mTolerance
	Distance tolerance for the simplification.

Detailed Description

Implementation of GeometrySimplifier using the "MapToPixel" algorithm.

Simplifies a geometry removing points within of the maximum distance difference that defines the MapToPixel info of a RenderContext request. This class enables simplify the geometries to be rendered in a MapCanvas target to speed up the vector drawing.

Definition at line 38 of file qgsmaptopixelgeometrysimplifier.h.

Member Enumeration Documentation

◆ SimplifyAlgorithm

enum QgsMapToPixelSimplifier::SimplifyAlgorithm

Types of simplification algorithms that can be used.

Enumerator
Distance	The simplification uses the distance between points to remove duplicate points.
SnapToGrid	The simplification uses a grid (similar to ST_SnapToGrid) to remove duplicate points.
Visvalingam	The simplification gives each point in a line an importance weighting, so that least important points are removed first.
SnappedToGridGlobal	Snap to a global grid based on the tolerance. Good for consistent results for incoming vertices, regardless of their feature.

Definition at line 42 of file qgsmaptopixelgeometrysimplifier.h.

◆ SimplifyFlag

enum QgsMapToPixelSimplifier::SimplifyFlag

Applicable simplification flags.

Enumerator
NoFlags	No simplification can be applied.
SimplifyGeometry	The geometries can be simplified using the current map2pixel context state.
SimplifyEnvelope	The geometries can be fully simplified by its BoundingBox.

Definition at line 54 of file qgsmaptopixelgeometrysimplifier.h.