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https://github.com/qgis/QGIS.git
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c49b5b777f
Rationale: - there was a lot of large objects passed by value, so potentially there's a speed bump from this - even for implicitly shared classes like QString/QList there's still a (small) cost for copying the objects when there's no reason to - it's the right thing to do!
63 lines
2.5 KiB
Plaintext
63 lines
2.5 KiB
Plaintext
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/** Job implementation that renders everything sequentially using a custom painter.
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*
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* Also supports synchronous rendering in main thread for cases when rendering in background
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* is not an option because of some technical limitations (e.g. printing to printer on some
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* platforms).
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*
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* @note added in 2.4
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*/
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class QgsMapRendererCustomPainterJob : QgsMapRendererJob
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{
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%TypeHeaderCode
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#include <qgsmaprenderercustompainterjob.h>
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%End
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public:
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QgsMapRendererCustomPainterJob( const QgsMapSettings& settings, QPainter* painter );
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~QgsMapRendererCustomPainterJob();
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virtual void start();
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virtual void cancel();
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virtual void waitForFinished();
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virtual bool isActive() const;
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virtual QgsLabelingResults* takeLabelingResults() /Transfer/;
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//! @note not available in python bindings
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// const LayerRenderJobs& jobs() const { return mLayerJobs; }
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/**
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* Wait for the job to be finished - and keep the thread's event loop running while waiting.
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*
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* With a call to waitForFinished(), the waiting is done with a synchronization primitive
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* and does not involve processing of messages. That may cause issues to code which requires
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* some events to be handled in the main thread. Some plugins hooking into the rendering
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* pipeline may require this in order to work properly - for example, OpenLayers plugin
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* which uses a QWebPage in the main thread.
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*
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* Ideally the "wait for finished" method should not be used at all. The code triggering
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* rendering should not need to actively wait for rendering to finish.
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*/
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void waitForFinishedWithEventLoop( const QEventLoop::ProcessEventsFlags& flags = QEventLoop::AllEvents );
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/**
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* Render the map synchronously in this thread. The function does not return until the map
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* is completely rendered.
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*
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* This is an alternative to ordinary API (using start() + waiting for finished() signal).
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* Users are discouraged to use this method unless they have a strong reason for doing it.
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* The synchronous rendering blocks the main thread, making the application unresponsive.
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* Also, it is not possible to cancel rendering while it is in progress.
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*/
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void renderSynchronously();
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protected slots:
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void futureFinished();
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protected:
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static void staticRender( QgsMapRendererCustomPainterJob* self ); // function to be used within the thread
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// these methods are called within worker thread
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void doRender();
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};
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