QGIS API Documentation  3.21.0-Master (5b68dc587e)
qgsmaplayerrenderer.h
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1 /***************************************************************************
2  qgsmaplayerrenderer.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 QGSMAPLAYERRENDERER_H
17 #define QGSMAPLAYERRENDERER_H
18 
19 #include <QStringList>
20 
21 #include "qgis_core.h"
22 #include "qgis_sip.h"
23 
24 class QgsFeedback;
25 class QgsRenderContext;
27 
54 class CORE_EXPORT QgsMapLayerRenderer
55 {
56  public:
57 
61  QgsMapLayerRenderer( const QString &layerID, QgsRenderContext *context = nullptr )
62  : mLayerID( layerID )
63  , mContext( context )
64  {}
65 
67 
74  virtual bool render() = 0;
75 
92  virtual bool forceRasterRender() const { return false; }
93 
98  virtual QgsFeedback *feedback() const { return nullptr; }
99 
101  QStringList errors() const { return mErrors; }
102 
104  QString layerId() const { return mLayerID; }
105 
111  QgsRenderContext *renderContext() { return mContext; }
112 
119  const QgsRenderContext *renderContext() const SIP_SKIP { return mContext; }
120 
127  bool isReadyToCompose() const { return mReadyToCompose; }
128 
139  virtual void setLayerRenderingTimeHint( int time ) SIP_SKIP { Q_UNUSED( time ) }
140 
149  QList< QgsRenderedItemDetails * > takeRenderedItemDetails() SIP_TRANSFERBACK;
150 
151  protected:
152  QStringList mErrors;
153  QString mLayerID;
154 
155  // TODO QGIS 4.0 - make false as default
156 
171  bool mReadyToCompose = true;
172 
181  static constexpr int MAX_TIME_TO_USE_CACHED_PREVIEW_IMAGE = 3000 SIP_SKIP;
182 
193  void appendRenderedItemDetails( QgsRenderedItemDetails *details SIP_TRANSFER );
194 
195  private:
196 
197  // TODO QGIS 4.0 - make reference instead of pointer!
198 
204  QgsRenderContext *mContext = nullptr;
205 
206  QList<QgsRenderedItemDetails *> mRenderedItemDetails;
207 };
208 
209 #endif // QGSMAPLAYERRENDERER_H
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition: qgsfeedback.h:45
Base class for utility classes that encapsulate information necessary for rendering of map layers.
virtual bool render()=0
Do the rendering (based on data stored in the class).
bool isReadyToCompose() const
Returns whether the renderer has already drawn (at least partially) some data.
QString layerId() const
Gets access to the ID of the layer rendered by this class.
virtual QgsFeedback * feedback() const
Access to feedback object of the layer renderer (may be nullptr)
virtual bool forceRasterRender() const
Returns true if the renderer must be rendered to a raster paint device (e.g.
virtual ~QgsMapLayerRenderer()
QStringList errors() const
Returns list of errors (problems) that happened during the rendering.
QgsRenderContext * renderContext()
Returns the render context associated with the renderer.
QgsMapLayerRenderer(const QString &layerID, QgsRenderContext *context=nullptr)
Constructor for QgsMapLayerRenderer, with the associated layerID and render context.
const QgsRenderContext * renderContext() const
Returns the render context associated with the renderer.
virtual void setLayerRenderingTimeHint(int time)
Sets approximate render time (in ms) for the layer to render.
Contains information about the context of a rendering operation.
Base class for detailed information about a rendered item.
#define SIP_SKIP
Definition: qgis_sip.h:126
#define SIP_TRANSFER
Definition: qgis_sip.h:36
#define SIP_TRANSFERBACK
Definition: qgis_sip.h:48