QGIS API Documentation  2.99.0-Master (c4aa4d0)
qgsrendercontext.cpp
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1 /***************************************************************************
2  qgsrendercontext.cpp
3  --------------------
4  begin : March 16, 2008
5  copyright : (C) 2008 by Marco Hugentobler
6  email : marco dot hugentobler at karto dot baug dot ethz dot ch
7  ***************************************************************************/
8 
9 /***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
17 
18 
19 #include "qgsrendercontext.h"
20 
21 #include "qgsmapsettings.h"
22 #include "qgsexpression.h"
23 #include "qgsvectorlayer.h"
25 #include "qgslogger.h"
26 #include "qgspoint.h"
27 
28 #define POINTS_TO_MM 2.83464567
29 #define INCH_TO_MM 25.4
30 
32  : mFlags( DrawEditingInfo | UseAdvancedEffects | DrawSelection | UseRenderingOptimization )
33 {
35  // For RenderMetersInMapUnits support, when rendering in Degrees, the Ellipsoid must be set
36  // - for Previews/Icons the default Extent can be used
37  mDistanceArea.setEllipsoid( mDistanceArea.sourceCrs().ellipsoidAcronym() );
38 }
39 
41  : mFlags( rh.mFlags )
42  , mPainter( rh.mPainter )
43  , mCoordTransform( rh.mCoordTransform )
44  , mDistanceArea( rh.mDistanceArea )
45  , mExtent( rh.mExtent )
46  , mMapToPixel( rh.mMapToPixel )
47  , mRenderingStopped( rh.mRenderingStopped )
48  , mScaleFactor( rh.mScaleFactor )
49  , mRendererScale( rh.mRendererScale )
50  , mLabelingEngine( rh.mLabelingEngine )
51  , mSelectionColor( rh.mSelectionColor )
52  , mVectorSimplifyMethod( rh.mVectorSimplifyMethod )
53  , mExpressionContext( rh.mExpressionContext )
54  , mGeometry( rh.mGeometry )
55  , mFeatureFilterProvider( rh.mFeatureFilterProvider ? rh.mFeatureFilterProvider->clone() : nullptr )
56  , mSegmentationTolerance( rh.mSegmentationTolerance )
57  , mSegmentationToleranceType( rh.mSegmentationToleranceType )
58  , mTransformContext( rh.mTransformContext )
59 #ifdef QGISDEBUG
60  , mHasTransformContext( rh.mHasTransformContext )
61 #endif
62 {
63 }
64 
66 {
67  mFlags = rh.mFlags;
68  mPainter = rh.mPainter;
69  mCoordTransform = rh.mCoordTransform;
70  mExtent = rh.mExtent;
71  mMapToPixel = rh.mMapToPixel;
72  mRenderingStopped = rh.mRenderingStopped;
73  mScaleFactor = rh.mScaleFactor;
74  mRendererScale = rh.mRendererScale;
75  mLabelingEngine = rh.mLabelingEngine;
76  mSelectionColor = rh.mSelectionColor;
77  mVectorSimplifyMethod = rh.mVectorSimplifyMethod;
78  mExpressionContext = rh.mExpressionContext;
79  mGeometry = rh.mGeometry;
80  mFeatureFilterProvider.reset( rh.mFeatureFilterProvider ? rh.mFeatureFilterProvider->clone() : nullptr );
81  mSegmentationTolerance = rh.mSegmentationTolerance;
82  mSegmentationToleranceType = rh.mSegmentationToleranceType;
83  mDistanceArea = rh.mDistanceArea;
84  mTransformContext = rh.mTransformContext;
85 #ifdef QGISDEBUG
86  mHasTransformContext = rh.mHasTransformContext;
87 #endif
88 
89  return *this;
90 }
91 
93 {
94  QgsRenderContext context;
95  context.setPainter( painter );
96  if ( painter && painter->device() )
97  {
98  context.setScaleFactor( painter->device()->logicalDpiX() / 25.4 );
99  }
100  else
101  {
102  context.setScaleFactor( 3.465 ); //assume 88 dpi as standard value
103  }
104  return context;
105 }
106 
108 {
109 #ifdef QGISDEBUG
110  if ( !mHasTransformContext )
111  qWarning( "No QgsCoordinateTransformContext context set for transform" );
112 #endif
113  return mTransformContext;
114 }
115 
117 {
118  mTransformContext = context;
119 #ifdef QGISDEBUG
120  mHasTransformContext = true;
121 #endif
122 }
123 
124 void QgsRenderContext::setFlags( QgsRenderContext::Flags flags )
125 {
126  mFlags = flags;
127 }
128 
130 {
131  if ( on )
132  mFlags |= flag;
133  else
134  mFlags &= ~flag;
135 }
136 
137 QgsRenderContext::Flags QgsRenderContext::flags() const
138 {
139  return mFlags;
140 }
141 
143 {
144  return mFlags.testFlag( flag );
145 }
146 
148 {
149  QgsRenderContext ctx;
150  ctx.setMapToPixel( mapSettings.mapToPixel() );
151  ctx.setExtent( mapSettings.visibleExtent() );
157  ctx.setSelectionColor( mapSettings.selectionColor() );
164  ctx.setScaleFactor( mapSettings.outputDpi() / 25.4 ); // = pixels per mm
165  ctx.setRendererScale( mapSettings.scale() );
166  ctx.setExpressionContext( mapSettings.expressionContext() );
167  ctx.setSegmentationTolerance( mapSettings.segmentationTolerance() );
169  ctx.mDistanceArea.setSourceCrs( mapSettings.destinationCrs(), mapSettings.transformContext() );
170  ctx.mDistanceArea.setEllipsoid( mapSettings.ellipsoid() );
171  ctx.setTransformContext( mapSettings.transformContext() );
172  //this flag is only for stopping during the current rendering progress,
173  //so must be false at every new render operation
174  ctx.setRenderingStopped( false );
175 
176  return ctx;
177 }
178 
180 {
181  return mFlags.testFlag( ForceVectorOutput );
182 }
183 
185 {
186  return mFlags.testFlag( UseAdvancedEffects );
187 }
188 
190 {
191  setFlag( UseAdvancedEffects, enabled );
192 }
193 
195 {
196  return mFlags.testFlag( DrawEditingInfo );
197 }
198 
200 {
201  return mFlags.testFlag( DrawSelection );
202 }
203 
205 {
206  mCoordTransform = t;
207 }
208 
210 {
211  setFlag( DrawEditingInfo, b );
212 }
213 
215 {
216  setFlag( ForceVectorOutput, force );
217 }
218 
220 {
221  setFlag( DrawSelection, showSelection );
222 }
223 
225 {
226  return mFlags.testFlag( UseRenderingOptimization );
227 }
228 
230 {
231  setFlag( UseRenderingOptimization, enabled );
232 }
233 
235 {
236  if ( ffp )
237  {
238  mFeatureFilterProvider.reset( ffp->clone() );
239  }
240  else
241  {
242  mFeatureFilterProvider.reset( nullptr );
243  }
244 }
245 
247 {
248  return mFeatureFilterProvider.get();
249 }
250 
252 {
253  double conversionFactor = 1.0;
254  switch ( unit )
255  {
257  conversionFactor = mScaleFactor;
258  break;
259 
261  conversionFactor = mScaleFactor / POINTS_TO_MM;
262  break;
263 
265  conversionFactor = mScaleFactor * INCH_TO_MM;
266  break;
267 
269  {
270  size = convertMetersToMapUnits( size );
272  // Fall through to RenderMapUnits with size in meters converted to size in MapUnits
273  FALLTHROUGH;
274  }
276  {
277  double mup = scale.computeMapUnitsPerPixel( *this );
278  if ( mup > 0 )
279  {
280  conversionFactor = 1.0 / mup;
281  }
282  else
283  {
284  conversionFactor = 1.0;
285  }
286  break;
287  }
289  conversionFactor = 1.0;
290  break;
291 
294  //no sensible value
295  conversionFactor = 1.0;
296  break;
297  }
298 
299  double convertedSize = size * conversionFactor;
300 
301  if ( unit == QgsUnitTypes::RenderMapUnits )
302  {
303  //check max/min size
304  if ( scale.minSizeMMEnabled )
305  convertedSize = std::max( convertedSize, scale.minSizeMM * mScaleFactor );
306  if ( scale.maxSizeMMEnabled )
307  convertedSize = std::min( convertedSize, scale.maxSizeMM * mScaleFactor );
308  }
309 
310  return convertedSize;
311 }
312 
313 double QgsRenderContext::convertToMapUnits( double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale ) const
314 {
315  double mup = mMapToPixel.mapUnitsPerPixel();
316 
317  switch ( unit )
318  {
320  {
321  size = convertMetersToMapUnits( size );
322  // Fall through to RenderMapUnits with values of meters converted to MapUnits
323  FALLTHROUGH;
324  }
326  {
327  // check scale
328  double minSizeMU = -DBL_MAX;
329  if ( scale.minSizeMMEnabled )
330  {
331  minSizeMU = scale.minSizeMM * mScaleFactor * mup;
332  }
333  if ( !qgsDoubleNear( scale.minScale, 0.0 ) )
334  {
335  minSizeMU = std::max( minSizeMU, size * ( mRendererScale / scale.minScale ) );
336  }
337  size = std::max( size, minSizeMU );
338 
339  double maxSizeMU = DBL_MAX;
340  if ( scale.maxSizeMMEnabled )
341  {
342  maxSizeMU = scale.maxSizeMM * mScaleFactor * mup;
343  }
344  if ( !qgsDoubleNear( scale.maxScale, 0.0 ) )
345  {
346  maxSizeMU = std::min( maxSizeMU, size * ( mRendererScale / scale.maxScale ) );
347  }
348  size = std::min( size, maxSizeMU );
349 
350  return size;
351  }
353  {
354  return size * mScaleFactor * mup;
355  }
357  {
358  return size * mScaleFactor * mup / POINTS_TO_MM;
359  }
361  {
362  return size * mScaleFactor * mup * INCH_TO_MM;
363  }
365  {
366  return size * mup;
367  }
368 
371  //no sensible value
372  return 0.0;
373  }
374  return 0.0;
375 }
376 
377 double QgsRenderContext::convertFromMapUnits( double sizeInMapUnits, QgsUnitTypes::RenderUnit outputUnit ) const
378 {
379  double mup = mMapToPixel.mapUnitsPerPixel();
380 
381  switch ( outputUnit )
382  {
384  {
385  return sizeInMapUnits / convertMetersToMapUnits( 1.0 );
386  }
388  {
389  return sizeInMapUnits;
390  }
392  {
393  return sizeInMapUnits / ( mScaleFactor * mup );
394  }
396  {
397  return sizeInMapUnits / ( mScaleFactor * mup / POINTS_TO_MM );
398  }
400  {
401  return sizeInMapUnits / ( mScaleFactor * mup * INCH_TO_MM );
402  }
404  {
405  return sizeInMapUnits / mup;
406  }
407 
410  //no sensible value
411  return 0.0;
412  }
413  return 0.0;
414 }
415 
416 double QgsRenderContext::convertMetersToMapUnits( double meters ) const
417 {
418  switch ( mDistanceArea.sourceCrs().mapUnits() )
419  {
421  return meters;
423  {
424  QgsPointXY pointCenter = mExtent.center();
425  // The Extent is in the sourceCrs(), when different from destinationCrs()
426  // - the point must be transformed, since DistanceArea uses the destinationCrs()
427  // Note: the default QgsCoordinateTransform() : authid() will return an empty String
428  if ( !mCoordTransform.isShortCircuited() )
429  {
430  pointCenter = mCoordTransform.transform( pointCenter );
431  }
432  return mDistanceArea.measureLineProjected( pointCenter, meters );
433  }
442  return ( meters * QgsUnitTypes::fromUnitToUnitFactor( QgsUnitTypes::DistanceMeters, mDistanceArea.sourceCrs().mapUnits() ) );
443  }
444  return meters;
445 }
void setForceVectorOutput(bool force)
Meters value as Map units.
Definition: qgsunittypes.h:109
double convertToMapUnits(double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale()) const
Converts a size from the specified units to map units.
Enable layer opacity and blending effects.
void setRenderingStopped(bool stopped)
double minSizeMM
The minimum size in millimeters, or 0.0 if unset.
Enable vector simplification and other rendering optimizations.
virtual QgsFeatureFilterProvider * clone() const =0
Create a clone of the feature filter provider.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context, which stores various information regarding which datum tran...
const QgsExpressionContext & expressionContext() const
Gets the expression context.
QgsCoordinateTransformContext transformContext() const
Returns the context's coordinate transform context, which stores various information regarding which ...
void setFlags(QgsRenderContext::Flags flags)
Set combination of flags that will be used for rendering.
Use antialiasing while drawing.
double convertFromMapUnits(double sizeInMapUnits, QgsUnitTypes::RenderUnit outputUnit) const
Converts a size from map units to the specified units.
void setCoordinateTransform(const QgsCoordinateTransform &t)
Sets coordinate transformation.
A class to represent a 2D point.
Definition: qgspointxy.h:43
void setSimplifyHints(SimplifyHints simplifyHints)
Sets the simplification hints of the vector layer managed.
void setRendererScale(double scale)
Sets the renderer map scale.
Whether to make extra effort to update map image with partially rendered layers (better for interacti...
void setTransformContext(const QgsCoordinateTransformContext &context)
Sets the context's coordinate transform context, which stores various information regarding which dat...
double computeMapUnitsPerPixel(const QgsRenderContext &c) const
Computes a map units per pixel scaling factor, respecting the minimum and maximum scales set for the ...
Flags flags() const
Return combination of flags used for rendering.
bool setEllipsoid(const QString &ellipsoid)
Sets the ellipsoid by its acronym.
Percentage of another measurement (e.g., canvas size, feature size)
Definition: qgsunittypes.h:105
Enable layer opacity and blending effects.
Whether vector selections should be shown in the rendered map.
void setExtent(const QgsRectangle &extent)
QgsRectangle visibleExtent() const
Return the actual extent derived from requested extent that takes takes output image size into accoun...
bool qgsDoubleNear(double a, double b, double epsilon=4 *DBL_EPSILON)
Compare two doubles (but allow some difference)
Definition: qgis.h:227
double maxScale
The maximum scale, or 0.0 if unset.
const QgsFeatureFilterProvider * featureFilterProvider() const
Get the filter feature provider used for additional filtering of rendered features.
bool minSizeMMEnabled
Whether the minimum size in mm should be respected.
QgsCoordinateReferenceSystem destinationCrs() const
returns CRS of destination coordinate reference system
Vector graphics should not be cached and drawn as raster images.
The QgsMapSettings class contains configuration for rendering of the map.
double convertMetersToMapUnits(double meters) const
Convert meter distances to active MapUnit values for QgsUnitTypes::RenderMetersInMapUnits.
void setSelectionColor(const QColor &color)
No simplification can be applied.
QString ellipsoidAcronym() const
Returns the ellipsoid acronym for the ellipsoid used by the CRS.
void setUseAdvancedEffects(bool enabled)
Used to enable or disable advanced effects such as blend modes.
void setScaleFactor(double factor)
Sets the scaling factor for the render to convert painter units to physical sizes.
#define FALLTHROUGH
Definition: qgis.h:524
QgsRenderContext & operator=(const QgsRenderContext &rh)
#define INCH_TO_MM
bool isShortCircuited() const
Returns true if the transform short circuits because the source and destination are equivalent...
Whether vector selections should be shown in the rendered map.
double scale() const
Returns the calculated map scale.
void setDrawEditingInformation(bool b)
Enable anti-aliasing for map rendering.
points (e.g., for font sizes)
Definition: qgsunittypes.h:107
static QgsRenderContext fromQPainter(QPainter *painter)
Creates a default render context given a pixel based QPainter destination.
bool drawEditingInformation() const
Draw bounds of symbols (for debugging/testing)
Degrees, for planar geographic CRS distance measurements.
Definition: qgsunittypes.h:51
void setPainter(QPainter *p)
Sets the destination QPainter for the render operation.
Abstract interface for use by classes that filter the features of a layer.
void setSegmentationToleranceType(QgsAbstractGeometry::SegmentationToleranceType type)
Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation...
Contains information about the context in which a coordinate transform is executed.
double mapUnitsPerPixel() const
Return current map units per pixel.
const QgsMapToPixel & mapToPixel() const
Draw bounds of symbols (for debugging/testing)
Vector graphics should not be cached and drawn as raster images.
Enable drawing of vertex markers for layers in editing mode.
QgsAbstractGeometry::SegmentationToleranceType segmentationToleranceType() const
Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation...
bool forceVectorOutput() const
QgsCoordinateReferenceSystem sourceCrs() const
Returns the source spatial reference system.
void setSegmentationTolerance(double tolerance)
Sets the segmentation tolerance applied when rendering curved geometries.
bool useRenderingOptimization() const
Returns true if the rendering optimization (geometry simplification) can be executed.
Draw map such that there are no problems between adjacent tiles.
Unknown distance unit.
Definition: qgsunittypes.h:54
Render is a 'canvas preview' render, and shortcuts should be taken to ensure fast rendering...
double outputDpi() const
Return DPI used for conversion between real world units (e.g.
Render is a 'canvas preview' render, and shortcuts should be taken to ensure fast rendering...
Contains information about the context of a rendering operation.
double convertToPainterUnits(double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale()) const
Converts a size from the specified units to painter units (pixels).
#define POINTS_TO_MM
QString ellipsoid() const
Returns ellipsoid's acronym.
double segmentationTolerance() const
Gets the segmentation tolerance applied when rendering curved geometries.
QPainter * painter()
Returns the destination QPainter for the render operation.
double maxSizeMM
The maximum size in millimeters, or 0.0 if unset.
Struct for storing maximum and minimum scales for measurements in map units.
Whether to make extra effort to update map image with partially rendered layers (better for interacti...
QgsPointXY transform(const QgsPointXY &point, TransformDirection direction=ForwardTransform) const
Transform the point from the source CRS to the destination CRS.
static QgsRenderContext fromMapSettings(const QgsMapSettings &mapSettings)
create initialized QgsRenderContext instance from given QgsMapSettings
double measureLineProjected(const QgsPointXY &p1, double distance=1, double azimuth=M_PI_2, QgsPointXY *projectedPoint=nullptr) const
Calculates the distance from one point with distance in meters and azimuth (direction) When the sourc...
bool useAdvancedEffects() const
Returns true if advanced effects such as blend modes such be used.
void setMapToPixel(const QgsMapToPixel &mtp)
Class for doing transforms between two map coordinate systems.
void setUseRenderingOptimization(bool enabled)
bool showSelection() const
Returns true if vector selections should be shown in the rendered map.
void setFlag(Flag flag, bool on=true)
Enable or disable a particular flag (other flags are not affected)
void setFeatureFilterProvider(const QgsFeatureFilterProvider *ffp)
Set a filter feature provider used for additional filtering of rendered features. ...
Enable vector simplification and other rendering optimizations.
void setSourceCrs(const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context)
Sets source spatial reference system crs.
bool testFlag(Flag flag) const
Check whether a particular flag is enabled.
QColor selectionColor() const
Get color that is used for drawing of selected vector features.
QgsPointXY center() const
Returns the center point of the rectangle.
Definition: qgsrectangle.h:166
void setShowSelection(const bool showSelection)
Sets whether vector selections should be shown in the rendered map.
bool testFlag(Flag flag) const
Check whether a particular flag is enabled.
Terrestrial miles.
Definition: qgsunittypes.h:50
Draw map such that there are no problems between adjacent tiles.
Flag
Enumeration of flags that affect rendering operations.
static Q_INVOKABLE double fromUnitToUnitFactor(QgsUnitTypes::DistanceUnit fromUnit, QgsUnitTypes::DistanceUnit toUnit)
Returns the conversion factor between the specified distance units.
Enable drawing of vertex markers for layers in editing mode.
double minScale
The minimum scale, or 0.0 if unset.
bool maxSizeMMEnabled
Whether the maximum size in mm should be respected.
RenderUnit
Rendering size units.
Definition: qgsunittypes.h:100
void setExpressionContext(const QgsExpressionContext &context)
Sets the expression context.