QGIS API Documentation  3.2.0-Bonn (bc43194)
qgsmapcanvastracer.cpp
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1 /***************************************************************************
2  qgsmapcanvastracer.cpp
3  ---------------------
4  begin : January 2016
5  copyright : (C) 2016 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 #include "qgsmapcanvastracer.h"
16 
17 #include "qgsapplication.h"
18 #include "qgsmapcanvas.h"
19 #include "qgsproject.h"
20 #include "qgsmessagebar.h"
21 #include "qgsmessagebaritem.h"
22 #include "qgssnappingutils.h"
23 #include "qgsvectorlayer.h"
24 #include "qgssnappingconfig.h"
25 #include "qgssettings.h"
26 
27 #include <QAction>
28 
29 
30 QHash<QgsMapCanvas *, QgsMapCanvasTracer *> QgsMapCanvasTracer::sTracers;
31 
32 
34  : mCanvas( canvas )
35  , mMessageBar( messageBar )
36 
37 {
38  sTracers.insert( canvas, this );
39 
40  // when things change we just invalidate the graph - and set up new parameters again only when necessary
45  connect( canvas, &QgsMapCanvas::currentLayerChanged, this, &QgsMapCanvasTracer::onCurrentLayerChanged );
47 
48  // arbitrarily chosen limit that should allow for fairly fast initialization
49  // of the underlying graph structure
50  setMaxFeatureCount( QgsSettings().value( QStringLiteral( "/qgis/digitizing/tracing_max_feature_count" ), 10000 ).toInt() );
51 }
52 
54 {
55  sTracers.remove( mCanvas );
56 }
57 
59 {
60  return sTracers.value( canvas, nullptr );
61 }
62 
64 {
65  Q_UNUSED( addingVertex );
66 
67  if ( !mMessageBar )
68  return;
69 
70  // remove previous message (if any)
71  mMessageBar->popWidget( mLastMessage );
72  mLastMessage = nullptr;
73 
74  QString message;
75  switch ( err )
76  {
77  case ErrTooManyFeatures:
78  message = tr( "Disabled - there are too many features displayed. Try zooming in or disable some layers." );
79  break;
80  case ErrNone:
81  default:
82  break;
83  }
84 
85  if ( message.isEmpty() && hasTopologyProblem() )
86  {
87  message = tr( "Tracing may not work correctly. Please check topology of the input layers." );
88  }
89 
90  if ( message.isEmpty() )
91  return;
92 
93  mLastMessage = new QgsMessageBarItem( tr( "Tracing" ), message, Qgis::Warning,
94  QgsSettings().value( QStringLiteral( "/qgis/messageTimeout" ), 5 ).toInt() );
95  mMessageBar->pushItem( mLastMessage );
96 }
97 
99 {
101  setExtent( mCanvas->extent() );
102 
103  QList<QgsVectorLayer *> layers;
104  QList<QgsMapLayer *> visibleLayers = mCanvas->mapSettings().layers();
105 
106  switch ( mCanvas->snappingUtils()->config().mode() )
107  {
108  default:
110  {
111  QgsVectorLayer *vl = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );
112  if ( vl && visibleLayers.contains( vl ) )
113  layers << vl;
114  }
115  break;
117  Q_FOREACH ( QgsMapLayer *layer, visibleLayers )
118  {
119  QgsVectorLayer *vl = qobject_cast<QgsVectorLayer *>( layer );
120  if ( vl )
121  layers << vl;
122  }
123  break;
125  Q_FOREACH ( const QgsSnappingUtils::LayerConfig &cfg, mCanvas->snappingUtils()->layers() )
126  {
127  if ( visibleLayers.contains( cfg.layer ) )
128  layers << cfg.layer;
129  }
130  break;
131  }
132 
133  setLayers( layers );
134 }
135 
136 void QgsMapCanvasTracer::onCurrentLayerChanged()
137 {
138  // no need to bother if we are not snapping
139  if ( mCanvas->snappingUtils()->config().mode() == QgsSnappingConfig::ActiveLayer )
140  invalidateGraph();
141 }
QList< QgsVectorLayer * > layers() const
Gets layers used for tracing.
Definition: qgstracer.h:52
Base class for all map layer types.
Definition: qgsmaplayer.h:61
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context, which stores various information regarding which datum tran...
SnappingMode mode() const
Returns the mode (all layers, active layer, per layer settings)
This class is a composition of two QSettings instances:
Definition: qgssettings.h:58
void setExtent(const QgsRectangle &extent)
Sets extent to which graph&#39;s features will be limited (empty extent means no limit) ...
Definition: qgstracer.cpp:588
A bar for displaying non-blocking messages to the user.
Definition: qgsmessagebar.h:45
On all vector layers.
QList< QgsMapLayer * > layers() const
Gets list of layers for map rendering The layers are stored in the reverse order of how they are rend...
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:74
bool hasTopologyProblem() const
Whether there was an error during graph creation due to noding exception, indicating some input data ...
Definition: qgstracer.h:120
QgsCoordinateReferenceSystem destinationCrs() const
returns CRS of destination coordinate reference system
Extension of QgsTracer that provides extra functionality:
static QgsMapCanvasTracer * tracerForCanvas(QgsMapCanvas *canvas)
Retrieve instance of this class associated with given canvas (if any).
void setDestinationCrs(const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context)
Sets the crs and transform context used for tracing.
Definition: qgstracer.cpp:581
bool popWidget(QgsMessageBarItem *item)
Remove the passed widget from the bar (if previously added), then display the next one in the stack i...
Max feature count threshold was reached while reading features.
Definition: qgstracer.h:126
QList< QgsSnappingUtils::LayerConfig > layers() const
Query layers used for snapping.
QgsRectangle extent() const
Returns the current zoom extent of the map canvas.
PathError
Possible errors that may happen when calling findShortestPath()
Definition: qgstracer.h:123
void destinationCrsChanged()
Emitted when map CRS has changed.
On a per layer configuration basis.
void transformContextChanged()
Emitted when the canvas transform context is changed.
void currentLayerChanged(QgsMapLayer *layer)
Emitted when the current layer is changed.
void configChanged(const QgsSnappingConfig &snappingConfig)
Emitted when the snapping settings object changes.
QgsMapLayer * currentLayer()
returns current layer (set by legend widget)
const QgsMapSettings & mapSettings() const
Gets access to properties used for map rendering.
void reportError(PathError err, bool addingVertex)
Report a path finding error to the user.
void pushItem(QgsMessageBarItem *item)
Display a message item on the bar after hiding the currently visible one and putting it in a stack...
void setMaxFeatureCount(int count)
Gets maximum possible number of features in graph. If the number is exceeded, graph is not created...
Definition: qgstracer.h:102
QgsSnappingConfig config
void configure() override
Sets configuration from current snapping settings and canvas settings.
QgsVectorLayer * layer
The layer to configure.
Configures how a certain layer should be handled in a snapping operation.
void invalidateGraph()
Destroy the existing graph structure if any (de-initialize)
Definition: qgstracer.cpp:628
QgsMapCanvasTracer(QgsMapCanvas *canvas, QgsMessageBar *messageBar=nullptr)
Create tracer associated with a particular map canvas, optionally message bar for reporting...
No error.
Definition: qgstracer.h:125
QgsSnappingUtils * snappingUtils() const
Returns snapping utility class that is associated with map canvas.
Represents a vector layer which manages a vector based data sets.
void extentsChanged()
Emitted when the extents of the map change.
void setLayers(const QList< QgsVectorLayer *> &layers)
Sets layers used for tracing.
Definition: qgstracer.cpp:555
void layersChanged()
Emitted when a new set of layers has been received.