QgsTask task which draws a map to an image file or a painter as a background task. More...

#include <qgsmaprenderertask.h>

Inheritance diagram for QgsMapRendererTask:

Public Types
enum	ErrorType { ImageAllocationFail = 1 , ImageSaveFail , ImageUnsupportedFormat }
	Error type. More...

Public Types inherited from QgsTask
enum	Flag { CanCancel = 1 << 1 , CancelWithoutPrompt = 1 << 2 , Hidden = 1 << 3 , Silent = 1 << 4 , AllFlags = CanCancel }
	Task flags. More...

enum	SubTaskDependency { SubTaskIndependent = 0 , ParentDependsOnSubTask }
	Controls how subtasks relate to their parent task. More...

enum	TaskStatus { Queued , OnHold , Running , Complete , Terminated }
	Status of tasks. More...

Signals
void	errorOccurred (int error)
	Emitted when map rendering failed.

void	renderingComplete ()
	Emitted when the map rendering is successfully completed.

Signals inherited from QgsTask
void	begun ()
	Will be emitted by task to indicate its commencement.

void	progressChanged (double progress)
	Will be emitted by task when its progress changes.

void	statusChanged (int status)
	Will be emitted by task when its status changes.

void	taskCompleted ()
	Will be emitted by task to indicate its successful completion.

void	taskTerminated ()
	Will be emitted by task if it has terminated for any reason other then completion (e.g., when a task has been canceled or encountered an internal error).

Public Member Functions
	QgsMapRendererTask (const QgsMapSettings &ms, const QString &fileName, const QString &fileFormat=QString("PNG"), bool forceRaster=false, QgsTask::Flags flags=QgsTask::CanCancel, bool geoPdf=false, const QgsAbstractGeoPdfExporter::ExportDetails &geoPdfExportDetails=QgsAbstractGeoPdfExporter::ExportDetails())
	Constructor for QgsMapRendererTask to render a map to an image file.

	QgsMapRendererTask (const QgsMapSettings &ms, QPainter *p)
	Constructor for QgsMapRendererTask to render a map to a QPainter object.

	~QgsMapRendererTask () override

void	addAnnotations (const QList< QgsAnnotation * > &annotations)
	Adds annotations to be rendered on the map.

void	addDecorations (const QList< QgsMapDecoration * > &decorations)
	Adds decorations to be rendered on the map.

void	cancel () override
	Notifies the task that it should terminate.

void	setExportMetadata (bool exportMetadata)
	Sets whether metadata such as title and subject will be exported whenever possible.

void	setSaveWorldFile (bool save)
	Sets whether the image file will be georeferenced (embedded or via a world file).

Public Member Functions inherited from QgsTask
	QgsTask (const QString &description=QString(), QgsTask::Flags flags=AllFlags)
	Constructor for QgsTask.

	~QgsTask () override

void	addSubTask (QgsTask *subTask, const QgsTaskList &dependencies=QgsTaskList(), SubTaskDependency subTaskDependency=SubTaskIndependent)
	Adds a subtask to this task.

bool	canCancel () const
	Returns `true` if the task can be canceled.

QList< QgsMapLayer * >	dependentLayers () const
	Returns the list of layers on which the task depends.

QString	description () const
	Returns the task's description.

qint64	elapsedTime () const
	Returns the elapsed time since the task commenced, in milliseconds.

Flags	flags () const
	Returns the flags associated with the task.

void	hold ()
	Places the task on hold.

bool	isActive () const
	Returns `true` if the task is active, ie it is not complete and has not been canceled.

double	progress () const
	Returns the task's progress (between 0.0 and 100.0)

void	setDependentLayers (const QList< QgsMapLayer * > &dependentLayers)
	Sets a list of layers on which the task depends.

void	setDescription (const QString &description)
	Sets the task's description.

TaskStatus	status () const
	Returns the current task status.

void	unhold ()
	Releases the task from being held.

bool	waitForFinished (int timeout=30000)
	Blocks the current thread until the task finishes or a maximum of timeout milliseconds.

Protected Member Functions
void	finished (bool result) override
	If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination).

bool	run () override
	Performs the task's operation.

Protected Member Functions inherited from QgsTask
bool	isCanceled () const
	Will return `true` if task should terminate ASAP.

Additional Inherited Members
Protected Slots inherited from QgsTask
void	setProgress (double progress)
	Sets the task's current progress.

Detailed Description

QgsTask task which draws a map to an image file or a painter as a background task.

This can be used to draw maps without blocking the QGIS interface.

Since: QGIS 3.0

Definition at line 44 of file qgsmaprenderertask.h.

Member Enumeration Documentation

◆ ErrorType

enum QgsMapRendererTask::ErrorType

Error type.

Enumerator

ImageAllocationFail

Image allocation failure.

ImageSaveFail

Image save failure.

ImageUnsupportedFormat

Format is unsupported on the platform.

Since: QGIS 3.4

Definition at line 51 of file qgsmaprenderertask.h.

Constructor & Destructor Documentation

◆ QgsMapRendererTask() [1/2]

QgsMapRendererTask::QgsMapRendererTask	(	const QgsMapSettings &	ms,
		const QString &	fileName,
		const QString &	fileFormat = `QString( "PNG" )`,
		bool	forceRaster = `false`,
		QgsTask::Flags	flags = `QgsTask::CanCancel`,
		bool	geoPdf = `false`,
		const QgsAbstractGeoPdfExporter::ExportDetails &	geoPdfExportDetails = `QgsAbstractGeoPdfExporter::ExportDetails()`
	)

Constructor for QgsMapRendererTask to render a map to an image file.

If the output fileFormat is set to PDF, the geoPdf argument controls whether a GeoPDF file is created. See QgsAbstractGeoPdfExporter::geoPDFCreationAvailable() for conditions on GeoPDF creation availability.

Since QGIS 3.26 the optional flags argument can be used to control the task flags.

Definition at line 119 of file qgsmaprenderertask.cpp.

◆ QgsMapRendererTask() [2/2]

QgsMapRendererTask::QgsMapRendererTask	(	const QgsMapSettings &	ms,
		QPainter *	p
	)

Constructor for QgsMapRendererTask to render a map to a QPainter object.

Definition at line 132 of file qgsmaprenderertask.cpp.

◆ ~QgsMapRendererTask()

QgsMapRendererTask::~QgsMapRendererTask ( )

overridedefault

Member Function Documentation

◆ addAnnotations()

void QgsMapRendererTask::addAnnotations ( const QList< QgsAnnotation * > & annotations )

Adds annotations to be rendered on the map.

Definition at line 142 of file qgsmaprenderertask.cpp.

◆ addDecorations()

void QgsMapRendererTask::addDecorations ( const QList< QgsMapDecoration * > & decorations )

Adds decorations to be rendered on the map.

Definition at line 154 of file qgsmaprenderertask.cpp.

◆ cancel()

void QgsMapRendererTask::cancel ( )

overridevirtual

Notifies the task that it should terminate.

Calling this is not guaranteed to immediately end the task, rather it sets the isCanceled() flag which task subclasses can check and terminate their operations at an appropriate time. Any subtasks owned by this task will also be canceled. Derived classes must ensure that the base class implementation is called from any overridden version.

See also: isCanceled()

Reimplemented from QgsTask.

Definition at line 160 of file qgsmaprenderertask.cpp.

◆ errorOccurred

void QgsMapRendererTask::errorOccurred ( int error )

signal

Emitted when map rendering failed.

◆ finished()

void QgsMapRendererTask::finished ( bool result )

overrideprotectedvirtual

If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination).

The result argument reflects whether the task was successfully completed or not. This method is always called from the main thread, so it is safe to create widgets and perform other operations which require the main thread. However, the GUI will be blocked for the duration of this method so tasks should avoid performing any lengthy operations here.

Reimplemented from QgsTask.

Definition at line 426 of file qgsmaprenderertask.cpp.

◆ renderingComplete

void QgsMapRendererTask::renderingComplete ( )

signal

Emitted when the map rendering is successfully completed.

◆ run()

bool QgsMapRendererTask::run ( )

overrideprotectedvirtual

Performs the task's operation.

This method will be called when the task commences (ie via calling start() ), and subclasses should implement the operation they wish to perform in the background within this method.

A task must return a boolean value to indicate whether the task was completed successfully or terminated before completion.

Implements QgsTask.

Definition at line 170 of file qgsmaprenderertask.cpp.

◆ setExportMetadata()

void QgsMapRendererTask::setExportMetadata ( bool exportMetadata )

inline

Sets whether metadata such as title and subject will be exported whenever possible.

Definition at line 114 of file qgsmaprenderertask.h.

◆ setSaveWorldFile()

void QgsMapRendererTask::setSaveWorldFile ( bool save )

inline

Sets whether the image file will be georeferenced (embedded or via a world file).

Definition at line 109 of file qgsmaprenderertask.h.

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

/build/qgis-3.34.0+99sid/src/core/maprenderer/qgsmaprenderertask.h
/build/qgis-3.34.0+99sid/src/core/maprenderer/qgsmaprenderertask.cpp

Public Types

Signals

Public Member Functions

Protected Member Functions

Additional Inherited Members