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       1                 :            : /***************************************************************************
       2                 :            :   qgsmaprenderercustompainterjob.h
       3                 :            :   --------------------------------------
       4                 :            :   Date                 : December 2013
       5                 :            :   Copyright            : (C) 2013 by Martin Dobias
       6                 :            :   Email                : wonder dot sk at gmail dot com
       7                 :            :  ***************************************************************************
       8                 :            :  *                                                                         *
       9                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      10                 :            :  *   it under the terms of the GNU General Public License as published by  *
      11                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      12                 :            :  *   (at your option) any later version.                                   *
      13                 :            :  *                                                                         *
      14                 :            :  ***************************************************************************/
      15                 :            : 
      16                 :            : #ifndef QGSMAPRENDERERCUSTOMPAINTERJOB_H
      17                 :            : #define QGSMAPRENDERERCUSTOMPAINTERJOB_H
      18                 :            : 
      19                 :            : #include "qgis_core.h"
      20                 :            : #include "qgis_sip.h"
      21                 :            : #include "qgsmaprendererjob.h"
      22                 :            : 
      23                 :            : #include <QEventLoop>
      24                 :            : 
      25                 :            : /**
      26                 :            :  * \ingroup core
      27                 :            :  * \brief Abstract base class for map renderer jobs which use custom painters.
      28                 :            :  *
      29                 :            :  * \since QGIS 3.10
      30                 :            :  */
      31                 :          0 : class CORE_EXPORT QgsMapRendererAbstractCustomPainterJob : public QgsMapRendererJob
      32                 :            : {
      33                 :            :     Q_OBJECT
      34                 :            :   public:
      35                 :            : 
      36                 :            :     /**
      37                 :            :      * Constructor for QgsMapRendererAbstractCustomPainterJob, using the given
      38                 :            :      * map \a settings.
      39                 :            :      */
      40                 :            :     QgsMapRendererAbstractCustomPainterJob( const QgsMapSettings &settings );
      41                 :            : 
      42                 :            :   protected:
      43                 :            : 
      44                 :            :     /**
      45                 :            :      * Prepares the given \a painter ready for a map render.
      46                 :            :      *
      47                 :            :      * The \a backgroundColor argument specifies the color to use for the map's background.
      48                 :            :      */
      49                 :            :     void preparePainter( QPainter *painter, const QColor &backgroundColor = Qt::transparent );
      50                 :            : 
      51                 :            : };
      52                 :            : 
      53                 :            : /**
      54                 :            :  * \ingroup core
      55                 :            :  * \brief Job implementation that renders everything sequentially using a custom painter.
      56                 :            :  *
      57                 :            :  * Also supports synchronous rendering in main thread for cases when rendering in background
      58                 :            :  * is not an option because of some technical limitations (e.g. printing to printer on some
      59                 :            :  * platforms).
      60                 :            :  *
      61                 :            :  * \since QGIS 2.4
      62                 :            :  */
      63                 :            : class CORE_EXPORT QgsMapRendererCustomPainterJob : public QgsMapRendererAbstractCustomPainterJob
      64                 :            : {
      65                 :            :     Q_OBJECT
      66                 :            :   public:
      67                 :            :     QgsMapRendererCustomPainterJob( const QgsMapSettings &settings, QPainter *painter );
      68                 :            :     ~QgsMapRendererCustomPainterJob() override;
      69                 :            : 
      70                 :            :     void start() override;
      71                 :            :     void cancel() override;
      72                 :            :     void cancelWithoutBlocking() override;
      73                 :            :     void waitForFinished() override;
      74                 :            :     bool isActive() const override;
      75                 :            :     bool usedCachedLabels() const override;
      76                 :            :     QgsLabelingResults *takeLabelingResults() SIP_TRANSFER override;
      77                 :            : 
      78                 :            :     //! \note not available in Python bindings
      79                 :          0 :     const LayerRenderJobs &jobs() const { return mLayerJobs; } SIP_SKIP
      80                 :            : 
      81                 :            :     /**
      82                 :            :      * Wait for the job to be finished - and keep the thread's event loop running while waiting.
      83                 :            :      *
      84                 :            :      * With a call to waitForFinished(), the waiting is done with a synchronization primitive
      85                 :            :      * and does not involve processing of messages. That may cause issues to code which requires
      86                 :            :      * some events to be handled in the main thread. Some plugins hooking into the rendering
      87                 :            :      * pipeline may require this in order to work properly - for example, OpenLayers plugin
      88                 :            :      * which uses a QWebPage in the main thread.
      89                 :            :      *
      90                 :            :      * Ideally the "wait for finished" method should not be used at all. The code triggering
      91                 :            :      * rendering should not need to actively wait for rendering to finish.
      92                 :            :      */
      93                 :            :     void waitForFinishedWithEventLoop( QEventLoop::ProcessEventsFlags flags = QEventLoop::AllEvents );
      94                 :            : 
      95                 :            :     /**
      96                 :            :      * Render the map synchronously in this thread. The function does not return until the map
      97                 :            :      * is completely rendered.
      98                 :            :      *
      99                 :            :      * This is an alternative to ordinary API (using start() + waiting for finished() signal).
     100                 :            :      * Users are discouraged to use this method unless they have a strong reason for doing it.
     101                 :            :      * The synchronous rendering blocks the main thread, making the application unresponsive.
     102                 :            :      * Also, it is not possible to cancel rendering while it is in progress.
     103                 :            :      */
     104                 :            :     void renderSynchronously();
     105                 :            : 
     106                 :            :     /**
     107                 :            :      * Prepares the job for rendering synchronously in a background thread.
     108                 :            :      *
     109                 :            :      * Must be called from the main thread.
     110                 :            :      *
     111                 :            :      * This is an alternative to ordinary API (using start() + waiting for finished() signal),
     112                 :            :      * and an alternative to renderSynchronously() (which should only ever be called from the main thread).
     113                 :            :      *
     114                 :            :      * \see renderPrepared()
     115                 :            :      * \since QGIS 3.10
     116                 :            :      */
     117                 :            :     void prepare();
     118                 :            : 
     119                 :            :     /**
     120                 :            :      * Render a pre-prepared job. Can be safely called in a background thread.
     121                 :            :      *
     122                 :            :      * Must be preceded by a call to prepare()
     123                 :            :      *
     124                 :            :      * This is an alternative to ordinary API (using start() + waiting for finished() signal),
     125                 :            :      * and an alternative to renderSynchronously() (which should only ever be called from the main thread).
     126                 :            :      *
     127                 :            :      * \since QGIS 3.10
     128                 :            :      */
     129                 :            :     void renderPrepared();
     130                 :            : 
     131                 :            :   private slots:
     132                 :            :     void futureFinished();
     133                 :            : 
     134                 :            :   private:
     135                 :            :     static void staticRender( QgsMapRendererCustomPainterJob *self ); // function to be used within the thread
     136                 :            : 
     137                 :            :     // these methods are called within worker thread
     138                 :            :     void doRender();
     139                 :            : 
     140                 :            :     QPainter *mPainter = nullptr;
     141                 :            :     QFuture<void> mFuture;
     142                 :            :     QFutureWatcher<void> mFutureWatcher;
     143                 :            :     std::unique_ptr< QgsLabelingEngine > mLabelingEngineV2;
     144                 :            : 
     145                 :            :     bool mActive;
     146                 :            :     LayerRenderJobs mLayerJobs;
     147                 :            :     LabelRenderJob mLabelJob;
     148                 :            :     bool mRenderSynchronously = false;
     149                 :            :     bool mPrepared = false;
     150                 :            :     bool mPrepareOnly = false;
     151                 :            : 
     152                 :            :     LayerRenderJobs mSecondPassLayerJobs;
     153                 :            : };
     154                 :            : 
     155                 :            : 
     156                 :            : #endif // QGSMAPRENDERERCUSTOMPAINTERJOB_H