Job implementation that renders everything sequentially using a custom painter. More...

#include <qgsmaprenderercustompainterjob.h>

Inheritance diagram for QgsMapRendererCustomPainterJob:

Public Member Functions
	QgsMapRendererCustomPainterJob (const QgsMapSettings &settings, QPainter *painter)

	~QgsMapRendererCustomPainterJob () override

void	cancel () override
	Stop the rendering job - does not return until the job has terminated. More...

void	cancelWithoutBlocking () override
	Triggers cancellation of the rendering job without blocking. More...

bool	isActive () const override
	Tell whether the rendering job is currently running in background. More...

const LayerRenderJobs &	jobs () const

void	prepare ()
	Prepares the job for rendering synchronously in a background thread. More...

void	renderPrepared ()
	Render a pre-prepared job. More...

void	renderSynchronously ()
	Render the map synchronously in this thread. More...

void	start () override
	Start the rendering job and immediately return. More...

QgsLabelingResults *	takeLabelingResults () override
	Gets pointer to internal labeling engine (in order to get access to the results). More...

bool	usedCachedLabels () const override
	Returns `true` if the render job was able to use a cached labeling solution. More...

void	waitForFinished () override
	Block until the job has finished. More...

void	waitForFinishedWithEventLoop (QEventLoop::ProcessEventsFlags flags=QEventLoop::AllEvents)
	Wait for the job to be finished - and keep the thread's event loop running while waiting. More...

Public Member Functions inherited from QgsMapRendererAbstractCustomPainterJob
	QgsMapRendererAbstractCustomPainterJob (const QgsMapSettings &settings)
	Constructor for QgsMapRendererAbstractCustomPainterJob, using the given map settings. More...

Public Member Functions inherited from QgsMapRendererJob
	QgsMapRendererJob (const QgsMapSettings &settings)

Errors	errors () const
	List of errors that happened during the rendering job - available when the rendering has been finished. More...

const QgsFeatureFilterProvider *	featureFilterProvider () const
	Returns the feature filter provider used by the QgsRenderContext of each LayerRenderJob. More...

const QgsMapSettings &	mapSettings () const
	Returns map settings with which this job was started. More...

QHash< QgsMapLayer *, int >	perLayerRenderingTime () const
	Returns the render time (in ms) per layer. More...

int	renderingTime () const
	Returns the total time it took to finish the job (in milliseconds). More...

void	setCache (QgsMapRendererCache *cache)
	Assign a cache to be used for reading and storing rendered images of individual layers. More...

void	setFeatureFilterProvider (const QgsFeatureFilterProvider *f)
	Set the feature filter provider used by the QgsRenderContext of each LayerRenderJob. More...

void	setLayerRenderingTimeHints (const QHash< QString, int > &hints)
	Sets approximate render times (in ms) for map layers. More...

Additional Inherited Members
Public Types inherited from QgsMapRendererJob
typedef QList< QgsMapRendererJob::Error >	Errors

Signals inherited from QgsMapRendererJob
void	finished ()
	emitted when asynchronous rendering is finished (or canceled). More...

void	renderingLayersFinished ()
	Emitted when the layers are rendered. More...

Static Public Attributes inherited from QgsMapRendererJob
static const QString	LABEL_CACHE_ID
	QgsMapRendererCache ID string for cached label image. More...

static const QString	LABEL_PREVIEW_CACHE_ID
	QgsMapRendererCache ID string for cached label image during preview compositions only. More...

Protected Member Functions inherited from QgsMapRendererAbstractCustomPainterJob
void	preparePainter (QPainter *painter, const QColor &backgroundColor=Qt::transparent)
	Prepares the given painter ready for a map render. More...

Protected Member Functions inherited from QgsMapRendererJob
void	cleanupJobs (LayerRenderJobs &jobs)

void	cleanupLabelJob (LabelRenderJob &job)
	Handles clean up tasks for a label job, including deletion of images and storing cached label results. More...

void	cleanupSecondPassJobs (LayerRenderJobs &jobs)

void	logRenderingTime (const LayerRenderJobs &jobs, const LayerRenderJobs &secondPassJobs, const LabelRenderJob &labelJob)

LayerRenderJobs	prepareJobs (QPainter painter, QgsLabelingEngine labelingEngine2, bool deferredPainterSet=false)
	Creates a list of layer rendering jobs and prepares them for later render. More...

bool	prepareLabelCache () const
	Prepares the cache for storing the result of labeling. More...

LabelRenderJob	prepareLabelingJob (QPainter painter, QgsLabelingEngine labelingEngine2, bool canUseLabelCache=true)
	Prepares a labeling job. More...

LayerRenderJobs	prepareSecondPassJobs (LayerRenderJobs &firstPassJobs, LabelRenderJob &labelJob)
	Prepares jobs for a second pass, if selective masks exist (from labels or symbol layers). More...

Static Protected Member Functions inherited from QgsMapRendererJob
static QImage	composeImage (const QgsMapSettings &settings, const LayerRenderJobs &jobs, const LabelRenderJob &labelJob, const QgsMapRendererCache *cache=nullptr)

static void	composeSecondPass (LayerRenderJobs &secondPassJobs, LabelRenderJob &labelJob)
	Compose second pass images into first pass images. More...

static Q_DECL_DEPRECATED void	drawLabeling (const QgsMapSettings &settings, QgsRenderContext &renderContext, QgsLabelingEngine labelingEngine2, QPainter painter)

static void	drawLabeling (QgsRenderContext &renderContext, QgsLabelingEngine labelingEngine2, QPainter painter)

static QImage	layerImageToBeComposed (const QgsMapSettings &settings, const LayerRenderJob &job, const QgsMapRendererCache *cache)

Protected Attributes inherited from QgsMapRendererJob
QgsMapRendererCache *	mCache = nullptr

Errors	mErrors

QHash< QString, int >	mLayerRenderingTimeHints
	Approximate expected layer rendering time per layer, by layer ID. More...

QHash< QgsWeakMapLayerPointer, int >	mPerLayerRenderingTime
	Render time (in ms) per layer, by layer ID. More...

bool	mRecordRenderingTime = true
	`true` if layer rendering time should be recorded. More...

QElapsedTimer	mRenderingStart

int	mRenderingTime = 0

QgsMapSettings	mSettings

Detailed Description

Job implementation that renders everything sequentially using a custom painter.

Also supports synchronous rendering in main thread for cases when rendering in background is not an option because of some technical limitations (e.g. printing to printer on some platforms).

Since: QGIS 2.4

Definition at line 63 of file qgsmaprenderercustompainterjob.h.

Constructor & Destructor Documentation

◆ QgsMapRendererCustomPainterJob()

QgsMapRendererCustomPainterJob::QgsMapRendererCustomPainterJob	(	const QgsMapSettings &	settings,
		QPainter *	painter
	)

Definition at line 62 of file qgsmaprenderercustompainterjob.cpp.

◆ ~QgsMapRendererCustomPainterJob()

QgsMapRendererCustomPainterJob::~QgsMapRendererCustomPainterJob ( )

override

Definition at line 71 of file qgsmaprenderercustompainterjob.cpp.

Member Function Documentation

◆ cancel()

void QgsMapRendererCustomPainterJob::cancel ( )

overridevirtual

Stop the rendering job - does not return until the job has terminated.

Does nothing if the rendering is not active.

Implements QgsMapRendererJob.

Definition at line 131 of file qgsmaprenderercustompainterjob.cpp.

◆ cancelWithoutBlocking()

void QgsMapRendererCustomPainterJob::cancelWithoutBlocking ( )

overridevirtual

Triggers cancellation of the rendering job without blocking.

The render job will continue to operate until it is able to cancel, at which stage the finished() signal will be emitted. Does nothing if the rendering is not active.

Implements QgsMapRendererJob.

Definition at line 155 of file qgsmaprenderercustompainterjob.cpp.

◆ isActive()

bool QgsMapRendererCustomPainterJob::isActive ( ) const

overridevirtual

Tell whether the rendering job is currently running in background.

Implements QgsMapRendererJob.

Definition at line 189 of file qgsmaprenderercustompainterjob.cpp.

◆ jobs()

const LayerRenderJobs& QgsMapRendererCustomPainterJob::jobs ( ) const

inline

Note: not available in Python bindings

Definition at line 79 of file qgsmaprenderercustompainterjob.h.

◆ prepare()

void QgsMapRendererCustomPainterJob::prepare ( )

Prepares the job for rendering synchronously in a background thread.

Must be called from the main thread.

This is an alternative to ordinary API (using start() + waiting for finished() signal), and an alternative to renderSynchronously() (which should only ever be called from the main thread).

See also: renderPrepared()

Since: QGIS 3.10

Definition at line 224 of file qgsmaprenderercustompainterjob.cpp.

◆ renderPrepared()

void QgsMapRendererCustomPainterJob::renderPrepared ( )

Render a pre-prepared job.

Can be safely called in a background thread.

Must be preceded by a call to prepare()

This is an alternative to ordinary API (using start() + waiting for finished() signal), and an alternative to renderSynchronously() (which should only ever be called from the main thread).

Since: QGIS 3.10

Definition at line 232 of file qgsmaprenderercustompainterjob.cpp.

◆ renderSynchronously()

void QgsMapRendererCustomPainterJob::renderSynchronously ( )

Render the map synchronously in this thread.

The function does not return until the map is completely rendered.

This is an alternative to ordinary API (using start() + waiting for finished() signal). Users are discouraged to use this method unless they have a strong reason for doing it. The synchronous rendering blocks the main thread, making the application unresponsive. Also, it is not possible to cancel rendering while it is in progress.

Definition at line 216 of file qgsmaprenderercustompainterjob.cpp.

◆ start()

void QgsMapRendererCustomPainterJob::start ( )

overridevirtual

Start the rendering job and immediately return.

Does nothing if the rendering is already in progress.

Implements QgsMapRendererJob.

Definition at line 78 of file qgsmaprenderercustompainterjob.cpp.

◆ takeLabelingResults()

QgsLabelingResults * QgsMapRendererCustomPainterJob::takeLabelingResults ( )

overridevirtual

Gets pointer to internal labeling engine (in order to get access to the results).

This should not be used if cached labeling was redrawn - see usedCachedLabels().

See also: usedCachedLabels()

Implements QgsMapRendererJob.

Definition at line 199 of file qgsmaprenderercustompainterjob.cpp.

◆ usedCachedLabels()

bool QgsMapRendererCustomPainterJob::usedCachedLabels ( ) const

overridevirtual

Returns true if the render job was able to use a cached labeling solution.

If so, any previously stored labeling results (see takeLabelingResults()) should be retained.

See also: takeLabelingResults()

Since: QGIS 3.0

Implements QgsMapRendererJob.

Definition at line 194 of file qgsmaprenderercustompainterjob.cpp.

◆ waitForFinished()

void QgsMapRendererCustomPainterJob::waitForFinished ( )

overridevirtual

Block until the job has finished.

Implements QgsMapRendererJob.

Definition at line 172 of file qgsmaprenderercustompainterjob.cpp.

◆ waitForFinishedWithEventLoop()

void QgsMapRendererCustomPainterJob::waitForFinishedWithEventLoop ( QEventLoop::ProcessEventsFlags flags = QEventLoop::AllEvents )

Wait for the job to be finished - and keep the thread's event loop running while waiting.

With a call to waitForFinished(), the waiting is done with a synchronization primitive and does not involve processing of messages. That may cause issues to code which requires some events to be handled in the main thread. Some plugins hooking into the rendering pipeline may require this in order to work properly - for example, OpenLayers plugin which uses a QWebPage in the main thread.

Ideally the "wait for finished" method should not be used at all. The code triggering rendering should not need to actively wait for rendering to finish.

Definition at line 208 of file qgsmaprenderercustompainterjob.cpp.

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

/build/qgis-3.18.1+99unstable/src/core/qgsmaprenderercustompainterjob.h
/build/qgis-3.18.1+99unstable/src/core/qgsmaprenderercustompainterjob.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QgsMapRendererCustomPainterJob()

◆ ~QgsMapRendererCustomPainterJob()

Member Function Documentation

◆ cancel()

◆ cancelWithoutBlocking()

◆ isActive()

◆ jobs()

◆ prepare()

◆ renderPrepared()

◆ renderSynchronously()

◆ start()

◆ takeLabelingResults()

◆ usedCachedLabels()

◆ waitForFinished()

◆ waitForFinishedWithEventLoop()