QGIS API Documentation  2.99.0-Master (08ee180)
qgsmaprendererjob.cpp
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1 /***************************************************************************
2  qgsmaprendererjob.cpp
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 #include "qgsmaprendererjob.h"
17 
18 #include <QPainter>
19 #include <QTime>
20 #include <QTimer>
21 #include <QtConcurrentMap>
22 #include <QSettings>
23 
24 #include "qgslogger.h"
25 #include "qgsrendercontext.h"
26 #include "qgsmaplayer.h"
27 #include "qgsmaplayerregistry.h"
28 #include "qgsmaplayerrenderer.h"
30 #include "qgsmaprenderercache.h"
31 #include "qgsmessagelog.h"
32 #include "qgspallabeling.h"
33 #include "qgsvectorlayerrenderer.h"
34 #include "qgsvectorlayer.h"
35 #include "qgscsexception.h"
36 
38  : mSettings( settings )
39  , mCache( nullptr )
40  , mRenderingTime( 0 )
41 {
42 }
43 
44 
46  : QgsMapRendererJob( settings )
47 {
48 }
49 
50 
52 {
53  return mErrors;
54 }
55 
57 {
58  mCache = cache;
59 }
60 
62 {
63  return mSettings;
64 }
65 
66 
68 {
69  bool split = false;
70 
71  try
72  {
73 #ifdef QGISDEBUG
74  // QgsLogger::debug<QgsRectangle>("Getting extent of canvas in layers CS. Canvas is ", extent, __FILE__, __FUNCTION__, __LINE__);
75 #endif
76  // Split the extent into two if the source CRS is
77  // geographic and the extent crosses the split in
78  // geographic coordinates (usually +/- 180 degrees,
79  // and is assumed to be so here), and draw each
80  // extent separately.
81  static const double splitCoord = 180.0;
82 
83  if ( ml->crs().isGeographic() )
84  {
85  if ( ml->type() == QgsMapLayer::VectorLayer && !ct.destinationCrs().isGeographic() )
86  {
87  // if we transform from a projected coordinate system check
88  // check if transforming back roughly returns the input
89  // extend - otherwise render the world.
92 
93  QgsDebugMsgLevel( QString( "\n0:%1 %2x%3\n1:%4\n2:%5 %6x%7 (w:%8 h:%9)" )
94  .arg( extent.toString() ).arg( extent.width() ).arg( extent.height() )
95  .arg( extent1.toString(), extent2.toString() ).arg( extent2.width() ).arg( extent2.height() )
96  .arg( fabs( 1.0 - extent2.width() / extent.width() ) )
97  .arg( fabs( 1.0 - extent2.height() / extent.height() ) )
98  , 3 );
99 
100  if ( fabs( 1.0 - extent2.width() / extent.width() ) < 0.5 &&
101  fabs( 1.0 - extent2.height() / extent.height() ) < 0.5 )
102  {
103  extent = extent1;
104  }
105  else
106  {
107  extent = QgsRectangle( -180.0, -90.0, 180.0, 90.0 );
108  }
109  }
110  else
111  {
112  // Note: ll = lower left point
113  QgsPoint ll = ct.transform( extent.xMinimum(), extent.yMinimum(),
115 
116  // and ur = upper right point
117  QgsPoint ur = ct.transform( extent.xMaximum(), extent.yMaximum(),
119 
120  QgsDebugMsg( QString( "in:%1 (ll:%2 ur:%3)" ).arg( extent.toString(), ll.toString(), ur.toString() ) );
121 
123 
124  QgsDebugMsg( QString( "out:%1 (w:%2 h:%3)" ).arg( extent.toString() ).arg( extent.width() ).arg( extent.height() ) );
125 
126  if ( ll.x() > ur.x() )
127  {
128  // the coordinates projected in reverse order than what one would expect.
129  // we are probably looking at an area that includes longitude of 180 degrees.
130  // we need to take into account coordinates from two intervals: (-180,x1) and (x2,180)
131  // so let's use (-180,180). This hopefully does not add too much overhead. It is
132  // more straightforward than rendering with two separate extents and more consistent
133  // for rendering, labeling and caching as everything is rendered just in one go
134  extent.setXMinimum( -splitCoord );
135  extent.setXMaximum( splitCoord );
136  }
137  }
138 
139  // TODO: the above rule still does not help if using a projection that covers the whole
140  // world. E.g. with EPSG:3857 the longitude spectrum -180 to +180 is mapped to approx.
141  // -2e7 to +2e7. Converting extent from -5e7 to +5e7 is transformed as -90 to +90,
142  // but in fact the extent should cover the whole world.
143  }
144  else // can't cross 180
145  {
146  if ( ct.destinationCrs().isGeographic() &&
147  ( extent.xMinimum() <= -180 || extent.xMaximum() >= 180 ||
148  extent.yMinimum() <= -90 || extent.yMaximum() >= 90 ) )
149  // Use unlimited rectangle because otherwise we may end up transforming wrong coordinates.
150  // E.g. longitude -200 to +160 would be understood as +40 to +160 due to periodicity.
151  // We could try to clamp coords to (-180,180) for lon resp. (-90,90) for lat,
152  // but this seems like a safer choice.
153  extent = QgsRectangle( -DBL_MAX, -DBL_MAX, DBL_MAX, DBL_MAX );
154  else
156  }
157  }
158  catch ( QgsCsException &cse )
159  {
160  Q_UNUSED( cse );
161  QgsDebugMsg( "Transform error caught" );
162  extent = QgsRectangle( -DBL_MAX, -DBL_MAX, DBL_MAX, DBL_MAX );
163  r2 = QgsRectangle( -DBL_MAX, -DBL_MAX, DBL_MAX, DBL_MAX );
164  }
165 
166  return split;
167 }
168 
169 
170 
172 {
173  LayerRenderJobs layerJobs;
174 
175  // render all layers in the stack, starting at the base
176  QListIterator<QString> li( mSettings.layers() );
177  li.toBack();
178 
179  if ( mCache )
180  {
181  bool cacheValid = mCache->init( mSettings.visibleExtent(), mSettings.scale() );
182  QgsDebugMsg( QString( "CACHE VALID: %1" ).arg( cacheValid ) );
183  Q_UNUSED( cacheValid );
184  }
185 
186  mGeometryCaches.clear();
187 
188  while ( li.hasPrevious() )
189  {
190  QString layerId = li.previous();
191 
192  QgsDebugMsgLevel( "Rendering at layer item " + layerId, 2 );
193 
195 
196  if ( !ml )
197  {
198  mErrors.append( Error( layerId, tr( "Layer not found in registry." ) ) );
199  continue;
200  }
201 
202  QgsDebugMsgLevel( QString( "layer %1: minscale:%2 maxscale:%3 scaledepvis:%4 blendmode:%5" )
203  .arg( ml->name() )
204  .arg( ml->minimumScale() )
205  .arg( ml->maximumScale() )
206  .arg( ml->hasScaleBasedVisibility() )
207  .arg( ml->blendMode() )
208  , 3 );
209 
210  if ( !ml->isInScaleRange( mSettings.scale() ) ) //|| mOverview )
211  {
212  QgsDebugMsgLevel( "Layer not rendered because it is not within the defined visibility scale range", 3 );
213  continue;
214  }
215 
218 
220  {
221  ct = mSettings.layerTransform( ml );
222  if ( ct.isValid() )
223  {
224  reprojectToLayerExtent( ml, ct, r1, r2 );
225  }
226  QgsDebugMsgLevel( "extent: " + r1.toString(), 3 );
227  if ( !r1.isFinite() || !r2.isFinite() )
228  {
229  mErrors.append( Error( layerId, tr( "There was a problem transforming the layer's extent. Layer skipped." ) ) );
230  continue;
231  }
232  }
233 
234  // Force render of layers that are being edited
235  // or if there's a labeling engine that needs the layer to register features
236  if ( mCache && ml->type() == QgsMapLayer::VectorLayer )
237  {
238  QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
239  if ( vl->isEditable() || ( labelingEngine2 && QgsPalLabeling::staticWillUseLayer( vl ) ) )
240  mCache->clearCacheImage( ml->id() );
241  }
242 
243  layerJobs.append( LayerRenderJob() );
244  LayerRenderJob& job = layerJobs.last();
245  job.cached = false;
246  job.img = nullptr;
247  job.blendMode = ml->blendMode();
248  job.opacity = 1.0;
249  if ( QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml ) )
250  {
251  job.opacity = 1.0 - vl->layerTransparency() / 100.0;
252  }
253  job.layerId = ml->id();
254  job.renderingTime = -1;
255 
257  job.context.setPainter( painter );
258  job.context.setLabelingEngineV2( labelingEngine2 );
260  job.context.setExtent( r1 );
261 
262  // if we can use the cache, let's do it and avoid rendering!
263  if ( mCache && !mCache->cacheImage( ml->id() ).isNull() )
264  {
265  job.cached = true;
266  job.img = new QImage( mCache->cacheImage( ml->id() ) );
267  job.renderer = nullptr;
268  job.context.setPainter( nullptr );
269  continue;
270  }
271 
272  // If we are drawing with an alternative blending mode then we need to render to a separate image
273  // before compositing this on the map. This effectively flattens the layer and prevents
274  // blending occurring between objects on the layer
275  if ( mCache || !painter || needTemporaryImage( ml ) )
276  {
277  // Flattened image for drawing when a blending mode is set
278  QImage * mypFlattenedImage = nullptr;
279  mypFlattenedImage = new QImage( mSettings.outputSize().width(),
280  mSettings.outputSize().height(),
282  if ( mypFlattenedImage->isNull() )
283  {
284  mErrors.append( Error( layerId, tr( "Insufficient memory for image %1x%2" ).arg( mSettings.outputSize().width() ).arg( mSettings.outputSize().height() ) ) );
285  delete mypFlattenedImage;
286  layerJobs.removeLast();
287  continue;
288  }
289 
290  job.img = mypFlattenedImage;
291  QPainter* mypPainter = new QPainter( job.img );
292  mypPainter->setRenderHint( QPainter::Antialiasing, mSettings.testFlag( QgsMapSettings::Antialiasing ) );
293  job.context.setPainter( mypPainter );
294  }
295 
296  bool hasStyleOverride = mSettings.layerStyleOverrides().contains( ml->id() );
297  if ( hasStyleOverride )
298  ml->styleManager()->setOverrideStyle( mSettings.layerStyleOverrides().value( ml->id() ) );
299 
300  job.renderer = ml->createMapRenderer( job.context );
301 
302  if ( hasStyleOverride )
304 
305  if ( mRequestedGeomCacheForLayers.contains( ml->id() ) )
306  {
307  if ( QgsVectorLayerRenderer* vlr = dynamic_cast<QgsVectorLayerRenderer*>( job.renderer ) )
308  {
309  vlr->setGeometryCachePointer( &mGeometryCaches[ ml->id()] );
310  }
311  }
312 
313  } // while (li.hasPrevious())
314 
315  return layerJobs;
316 }
317 
318 
320 {
321  for ( LayerRenderJobs::iterator it = jobs.begin(); it != jobs.end(); ++it )
322  {
323  LayerRenderJob& job = *it;
324  if ( job.img )
325  {
326  delete job.context.painter();
327  job.context.setPainter( nullptr );
328 
329  if ( mCache && !job.cached && !job.context.renderingStopped() )
330  {
331  QgsDebugMsg( "caching image for " + job.layerId );
332  mCache->setCacheImage( job.layerId, *job.img );
333  }
334 
335  delete job.img;
336  job.img = nullptr;
337  }
338 
339  if ( job.renderer )
340  {
341  Q_FOREACH ( const QString& message, job.renderer->errors() )
342  mErrors.append( Error( job.renderer->layerId(), message ) );
343 
344  delete job.renderer;
345  job.renderer = nullptr;
346  }
347  }
348 
349  jobs.clear();
350 
352 }
353 
354 
355 QImage QgsMapRendererJob::composeImage( const QgsMapSettings& settings, const LayerRenderJobs& jobs )
356 {
357  QImage image( settings.outputSize(), settings.outputImageFormat() );
358  image.fill( settings.backgroundColor().rgba() );
359 
360  QPainter painter( &image );
361 
362  for ( LayerRenderJobs::const_iterator it = jobs.constBegin(); it != jobs.constEnd(); ++it )
363  {
364  const LayerRenderJob& job = *it;
365 
366  painter.setCompositionMode( job.blendMode );
367  painter.setOpacity( job.opacity );
368 
369  Q_ASSERT( job.img );
370 
371  painter.drawImage( 0, 0, *job.img );
372  }
373 
374  painter.end();
375  return image;
376 }
377 
379 {
380  QSettings settings;
381  if ( !settings.value( QStringLiteral( "/Map/logCanvasRefreshEvent" ), false ).toBool() )
382  return;
383 
384  QMultiMap<int, QString> elapsed;
385  Q_FOREACH ( const LayerRenderJob& job, jobs )
386  elapsed.insert( job.renderingTime, job.layerId );
387 
388  QList<int> tt( elapsed.uniqueKeys() );
389  qSort( tt.begin(), tt.end(), qGreater<int>() );
390  Q_FOREACH ( int t, tt )
391  {
392  QgsMessageLog::logMessage( tr( "%1 ms: %2" ).arg( t ).arg( QStringList( elapsed.values( t ) ).join( QStringLiteral( ", " ) ) ), tr( "Rendering" ) );
393  }
394  QgsMessageLog::logMessage( QStringLiteral( "---" ), tr( "Rendering" ) );
395 }
bool restoreOverrideStyle()
Restore the original store after a call to setOverrideStyle()
const QgsMapSettings & mapSettings() const
Return map settings with which this job was started.
A rectangle specified with double values.
Definition: qgsrectangle.h:35
Base class for all map layer types.
Definition: qgsmaplayer.h:49
Abstract base class for map rendering implementations.
void setXMaximum(double x)
Set the maximum x value.
Definition: qgsrectangle.h:176
void cleanupJobs(LayerRenderJobs &jobs)
void setCoordinateTransform(const QgsCoordinateTransform &t)
Sets coordinate transformation.
void updateLayerGeometryCaches()
called when rendering has finished to update all layers&#39; geometry caches
QList< Error > Errors
static QImage composeImage(const QgsMapSettings &settings, const LayerRenderJobs &jobs)
#define QgsDebugMsg(str)
Definition: qgslogger.h:33
QStringList mRequestedGeomCacheForLayers
list of layer IDs for which the geometry cache should be updated
QgsMapLayer * mapLayer(const QString &theLayerId) const
Retrieve a pointer to a registered layer by layer ID.
void logRenderingTime(const LayerRenderJobs &jobs)
QMap< QString, QgsGeometryCache > mGeometryCaches
map of geometry caches
QColor backgroundColor() const
Get the background color of the map.
void clearCacheImage(const QString &layerId)
remove layer from the cache
bool hasCrsTransformEnabled() const
returns true if projections are enabled for this layer set
QgsRectangle transformBoundingBox(const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform, const bool handle180Crossover=false) const
Transforms a rectangle from the source CRS to the destination CRS.
bool renderingStopped() const
QgsCoordinateReferenceSystem destinationCrs() const
Returns the destination coordinate reference system, which the transform will transform coordinates t...
bool isInScaleRange(double scale) const
Tests whether the layer should be visible at the specified scale.
static bool reprojectToLayerExtent(const QgsMapLayer *ml, const QgsCoordinateTransform &ct, QgsRectangle &extent, QgsRectangle &r2)
Convenience function to project an extent into the layer source CRS, but also split it into two exten...
virtual bool isEditable() const override
Returns true if the provider is in editing mode.
QgsMapLayer::LayerType type() const
Returns the type of the layer.
Definition: qgsmaplayer.cpp:95
void setExtent(const QgsRectangle &extent)
QgsRectangle visibleExtent() const
Return the actual extent derived from requested extent that takes takes output image size into accoun...
void setCache(QgsMapRendererCache *cache)
Assign a cache to be used for reading and storing rendered images of individual layers.
The QgsMapSettings class contains configuration for rendering of the map.
QgsMapLayerStyleManager * styleManager() const
Get access to the layer&#39;s style manager.
static bool staticWillUseLayer(QgsVectorLayer *layer)
called to find out whether the layer is used for labeling
QString toString(bool automaticPrecision=false) const
returns string representation of form xmin,ymin xmax,ymax
void setCacheImage(const QString &layerId, const QImage &img)
set cached image for the specified layer ID
QString id() const
Returns the layer&#39;s unique ID, which is used to access this layer from QgsMapLayerRegistry.
QgsPoint transform(const QgsPoint &point, TransformDirection direction=ForwardTransform) const
Transform the point from the source CRS to the destination CRS.
#define QgsDebugMsgLevel(str, level)
Definition: qgslogger.h:34
bool init(const QgsRectangle &extent, double scale)
initialize cache: set new parameters and erase cache if parameters have changed
double scale() const
Return the calculated scale of the map.
Errors errors() const
List of errors that happened during the rendering job - available when the rendering has been finishe...
double width() const
Width of the rectangle.
Definition: qgsrectangle.h:211
Enable anti-aliasing for map rendering.
static void logMessage(const QString &message, const QString &tag=QString::null, MessageLevel level=WARNING)
add a message to the instance (and create it if necessary)
QImage::Format outputImageFormat() const
format of internal QImage, default QImage::Format_ARGB32_Premultiplied
void setPainter(QPainter *p)
QgsCoordinateReferenceSystem crs() const
Returns the layer&#39;s spatial reference system.
bool isGeographic() const
Returns whether the CRS is a geographic CRS (using lat/lon coordinates)
double minimumScale() const
Returns the minimum scale denominator at which the layer is visible.
double maximumScale() const
Returns the maximum scale denominator at which the layer is visible.
A class to represent a point.
Definition: qgspoint.h:111
QString toString() const
String representation of the point (x,y)
Definition: qgspoint.cpp:129
QgsMapSettings mSettings
bool isFinite() const
Returns true if the rectangle has finite boundaries.
double yMinimum() const
Get the y minimum value (bottom side of rectangle)
Definition: qgsrectangle.h:206
QgsCoordinateTransform layerTransform(QgsMapLayer *layer) const
Return coordinate transform from layer&#39;s CRS to destination CRS.
Implementation of threaded rendering for vector layers.
double xMaximum() const
Get the x maximum value (right side of rectangle)
Definition: qgsrectangle.h:191
The QgsLabelingEngine class provides map labeling functionality.
QMap< QString, QString > layerStyleOverrides() const
Get map of map layer style overrides (key: layer ID, value: style name) where a different style shoul...
LayerRenderJobs prepareJobs(QPainter *painter, QgsLabelingEngine *labelingEngine2)
static QgsMapLayerRegistry * instance()
Returns the instance pointer, creating the object on the first call.
QPainter * painter()
Transform from destination to source CRS.
int renderingTime
Time it took to render the layer in ms (it is -1 if not rendered or still rendering) ...
bool hasScaleBasedVisibility() const
Returns whether scale based visibility is enabled for the layer.
void setLabelingEngineV2(QgsLabelingEngine *engine2)
Assign new labeling engine.
static QgsRenderContext fromMapSettings(const QgsMapSettings &mapSettings)
create initialized QgsRenderContext instance from given QgsMapSettings
QString layerId() const
Get access to the ID of the layer rendered by this class.
QgsMapLayerRenderer * renderer
Class for doing transforms between two map coordinate systems.
double xMinimum() const
Get the x minimum value (left side of rectangle)
Definition: qgsrectangle.h:196
QgsRenderContext context
virtual QgsMapLayerRenderer * createMapRenderer(QgsRenderContext &rendererContext)=0
Return new instance of QgsMapLayerRenderer that will be used for rendering of given context...
QgsMapRendererQImageJob(const QgsMapSettings &settings)
double yMaximum() const
Get the y maximum value (top side of rectangle)
Definition: qgsrectangle.h:201
QImage cacheImage(const QString &layerId)
get cached image for the specified layer ID. Returns null image if it is not cached.
QString name
Read property of QString layerName.
Definition: qgsmaplayer.h:53
Transform from source to destination CRS.
QStringList errors() const
Return list of errors (problems) that happened during the rendering.
This class is responsible for keeping cache of rendered images of individual layers.
bool testFlag(Flag flag) const
Check whether a particular flag is enabled.
bool setOverrideStyle(const QString &styleDef)
Temporarily apply a different style to the layer.
Custom exception class for Coordinate Reference System related exceptions.
QList< LayerRenderJob > LayerRenderJobs
QStringList layers() const
Get list of layer IDs for map rendering The layers are stored in the reverse order of how they are re...
QPainter::CompositionMode blendMode
Represents a vector layer which manages a vector based data sets.
QgsMapRendererCache * mCache
bool needTemporaryImage(QgsMapLayer *ml)
QSize outputSize() const
Return the size of the resulting map image.
bool isNull(const QVariant &v)
QgsMapRendererJob(const QgsMapSettings &settings)
void setXMinimum(double x)
Set the minimum x value.
Definition: qgsrectangle.h:171
QPainter::CompositionMode blendMode() const
Returns the current blending mode for a layer.
double height() const
Height of the rectangle.
Definition: qgsrectangle.h:216
Structure keeping low-level rendering job information.
double x
Definition: qgspoint.h:115