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3b56b79f6d
In some cases canceling render jobs can take a long time. Eg when using database layers over a sloooooow connection, canceling a job can be blocked by minutes while waiting for the first batch of feature fetching to finish. (Since eg postgres features are fetched in batches of 2000 with no opportunity to abort mid-way through this). This meant that while the first render allows the GUI to remain responsive, any subsequent render operations which occured before the first render completes locks up the whole ui until the first render can finish cancellation. With this change, the render cancelation happens with blocking. It means that you can pan and zoom around a map over of slow connection without any ui locks.
111 lines
3.3 KiB
Plaintext
111 lines
3.3 KiB
Plaintext
class QgsMapRendererJob : QObject
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{
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%TypeHeaderCode
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#include <qgsmaprendererjob.h>
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%End
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public:
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QgsMapRendererJob( const QgsMapSettings& settings );
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virtual ~QgsMapRendererJob();
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//! Start the rendering job and immediately return.
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//! Does nothing if the rendering is already in progress.
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virtual void start() = 0;
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//! Stop the rendering job - does not return until the job has terminated.
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//! Does nothing if the rendering is not active.
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virtual void cancel() = 0;
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virtual void cancelWithoutBlocking() = 0;
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//! Block until the job has finished.
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virtual void waitForFinished() = 0;
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//! Tell whether the rendering job is currently running in background.
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virtual bool isActive() const = 0;
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virtual bool usedCachedLabels() const = 0;
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//! Get pointer to internal labeling engine (in order to get access to the results)
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virtual QgsLabelingResults* takeLabelingResults() = 0 /Transfer/;
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//! @note Added in QGIS 3.0
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//! Set the feature filter provider used by the QgsRenderContext of
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//! each LayerRenderJob.
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//! Ownership is not transferred and the provider must not be deleted
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//! before the render job.
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void setFeatureFilterProvider( const QgsFeatureFilterProvider *f );
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//! @note Added in QGIS 3.0
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//! Returns the feature filter provider used by the QgsRenderContext of
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//! each LayerRenderJob.
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const QgsFeatureFilterProvider* featureFilterProvider() const;
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struct Error
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{
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Error( const QString& lid, const QString& msg );
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QString layerID;
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QString message;
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};
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typedef QList<QgsMapRendererJob::Error> Errors;
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//! List of errors that happened during the rendering job - available when the rendering has been finished
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Errors errors() const;
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//! Assign a cache to be used for reading and storing rendered images of individual layers.
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//! Does not take ownership of the object.
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void setCache( QgsMapRendererCache* cache );
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//! Set which vector layers should be cached while rendering
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//! @note The way how geometries are cached is really suboptimal - this method may be removed in future releases
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void setRequestedGeometryCacheForLayers( const QStringList& layerIds );
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//! Find out how long it took to finish the job (in milliseconds)
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int renderingTime() const;
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/**
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* Return map settings with which this job was started.
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* @return A QgsMapSettings instance with render settings
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* @note added in 2.8
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*/
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const QgsMapSettings& mapSettings() const;
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signals:
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/**
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* Emitted when the layers are rendered.
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* Rendering labels is not yet done. If the fully rendered layer including labels is required use
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* finished() instead.
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*
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* @note Added in QGIS 3.0
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*/
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void renderingLayersFinished();
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//! emitted when asynchronous rendering is finished (or canceled).
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void finished();
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};
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/** Intermediate base class adding functionality that allows client to query the rendered image.
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* The image can be queried even while the rendering is still in progress to get intermediate result
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*
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* @note added in 2.4
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*/
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class QgsMapRendererQImageJob : QgsMapRendererJob
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{
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%TypeHeaderCode
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#include <qgsmaprendererjob.h>
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%End
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public:
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QgsMapRendererQImageJob( const QgsMapSettings& settings );
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//! Get a preview/resulting image
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virtual QImage renderedImage() = 0;
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};
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