QGIS API Documentation  2.99.0-Master (53aba61)
qgslayertreemapcanvasbridge.cpp
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1 /***************************************************************************
2  qgslayertreemapcanvasbridge.cpp
3  --------------------------------------
4  Date : May 2014
5  Copyright : (C) 2014 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 
17 
18 #include "qgslayertree.h"
19 #include "qgslayertreeutils.h"
20 #include "qgsmaplayer.h"
21 #include "qgsvectorlayer.h"
22 #include "qgsmapcanvas.h"
23 #include "qgsmapoverviewcanvas.h"
24 #include "qgsproject.h"
25 
27  : QObject( parent )
28  , mRoot( root )
29  , mCanvas( canvas )
30  , mPendingCanvasUpdate( false )
31  , mAutoSetupOnFirstLayer( true )
32  , mLastLayerCount( !root->findLayers().isEmpty() )
33 {
34  connect( root, &QgsLayerTreeGroup::customPropertyChanged, this, &QgsLayerTreeMapCanvasBridge::nodeCustomPropertyChanged );
35  connect( root, &QgsLayerTreeNode::visibilityChanged, this, &QgsLayerTreeMapCanvasBridge::nodeVisibilityChanged );
36  connect( root, &QgsLayerTree::layerOrderChanged, this, &QgsLayerTreeMapCanvasBridge::deferredSetCanvasLayers );
37 
39 }
40 
42 {
43  QList<QgsMapLayer *> canvasLayers, overviewLayers, allLayerOrder;
44 
45  if ( mRoot->hasCustomLayerOrder() )
46  {
47  Q_FOREACH ( QgsMapLayer *layer, mRoot->customLayerOrder() )
48  {
49  QgsLayerTreeLayer *nodeLayer = mRoot->findLayer( layer->id() );
50  if ( nodeLayer )
51  {
52  allLayerOrder << nodeLayer->layer();
53  if ( nodeLayer->isVisible() )
54  canvasLayers << nodeLayer->layer();
55  if ( nodeLayer->customProperty( QStringLiteral( "overview" ), 0 ).toInt() )
56  overviewLayers << nodeLayer->layer();
57  }
58  }
59  }
60  else
61  setCanvasLayers( mRoot, canvasLayers, overviewLayers, allLayerOrder );
62 
63  QList<QgsLayerTreeLayer *> layerNodes = mRoot->findLayers();
64  int currentLayerCount = layerNodes.count();
65  bool firstLayers = mAutoSetupOnFirstLayer && mLastLayerCount == 0 && currentLayerCount != 0;
66 
67  mCanvas->setLayers( canvasLayers );
68  if ( mOverviewCanvas )
69  mOverviewCanvas->setLayers( overviewLayers );
70 
71  if ( firstLayers )
72  {
73  // if we are moving from zero to non-zero layers, let's zoom to those data
74  mCanvas->zoomToFullExtent();
75  }
76 
77  if ( !mFirstCRS.isValid() )
78  {
79  // find out what is the first used CRS in case we may need to turn on OTF projections later
80  Q_FOREACH ( QgsLayerTreeLayer *layerNode, layerNodes )
81  {
82  if ( layerNode->layer() && layerNode->layer()->crs().isValid() )
83  {
84  mFirstCRS = layerNode->layer()->crs();
85  break;
86  }
87  }
88  }
89 
90  if ( mFirstCRS.isValid() && firstLayers )
91  {
92  QgsProject::instance()->setCrs( mFirstCRS );
93  }
94 
95  mLastLayerCount = currentLayerCount;
96  if ( currentLayerCount == 0 )
97  mFirstCRS = QgsCoordinateReferenceSystem();
98 
99  mPendingCanvasUpdate = false;
100 
101  emit canvasLayersChanged( canvasLayers );
102 }
103 
104 void QgsLayerTreeMapCanvasBridge::setCanvasLayers( QgsLayerTreeNode *node, QList<QgsMapLayer *> &canvasLayers, QList<QgsMapLayer *> &overviewLayers, QList<QgsMapLayer *> &allLayers )
105 {
106  if ( QgsLayerTree::isLayer( node ) )
107  {
108  QgsLayerTreeLayer *nodeLayer = QgsLayerTree::toLayer( node );
109  allLayers << nodeLayer->layer();
110  if ( nodeLayer->isVisible() )
111  canvasLayers << nodeLayer->layer();
112  if ( nodeLayer->customProperty( QStringLiteral( "overview" ), 0 ).toInt() )
113  overviewLayers << nodeLayer->layer();
114  }
115 
116  Q_FOREACH ( QgsLayerTreeNode *child, node->children() )
117  setCanvasLayers( child, canvasLayers, overviewLayers, allLayers );
118 }
119 
120 void QgsLayerTreeMapCanvasBridge::deferredSetCanvasLayers()
121 {
122  if ( mPendingCanvasUpdate )
123  return;
124 
125  mPendingCanvasUpdate = true;
126  QMetaObject::invokeMethod( this, "setCanvasLayers", Qt::QueuedConnection );
127 }
128 
129 void QgsLayerTreeMapCanvasBridge::nodeVisibilityChanged()
130 {
131  deferredSetCanvasLayers();
132 }
133 
134 void QgsLayerTreeMapCanvasBridge::nodeCustomPropertyChanged( QgsLayerTreeNode *node, const QString &key )
135 {
136  Q_UNUSED( node );
137  if ( key == QLatin1String( "overview" ) )
138  deferredSetCanvasLayers();
139 }
static QgsLayerTreeLayer * toLayer(QgsLayerTreeNode *node)
Cast node to a layer.
Definition: qgslayertree.h:74
Base class for all map layer types.
Definition: qgsmaplayer.h:54
void layerOrderChanged()
Emitted when the layer order has changed.
bool isVisible() const
Returns whether a node is really visible (ie checked and all its ancestors checked as well) ...
Q_INVOKABLE void setCanvasLayers()
force update of canvas layers from the layer tree. Normally this should not be needed to be called...
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:73
QList< QgsMapLayer * > customLayerOrder() const
The order in which layers will be rendered on the canvas.
QString id() const
Returns the layer&#39;s unique ID, which is used to access this layer from QgsProject.
QList< QgsLayerTreeNode * > children()
Get list of children of the node. Children are owned by the parent.
Namespace with helper functions for layer tree operations.
Definition: qgslayertree.h:31
void setLayers(const QList< QgsMapLayer *> &layers)
updates layer set for overview
QVariant customProperty(const QString &key, const QVariant &defaultValue=QVariant()) const
Read a custom property from layer. Properties are stored in a map and saved in project file...
void setCrs(const QgsCoordinateReferenceSystem &crs)
Sets the project&#39;s native coordinate reference system.
Definition: qgsproject.cpp:449
QgsCoordinateReferenceSystem crs() const
Returns the layer&#39;s spatial reference system.
static bool isLayer(const QgsLayerTreeNode *node)
Check whether the node is a valid layer node.
Definition: qgslayertree.h:52
This class is a base class for nodes in a layer tree.
bool hasCustomLayerOrder() const
Determines if the layer order should be derived from the layer tree or if a custom override order sha...
void canvasLayersChanged(const QList< QgsMapLayer * > &layers)
Emitted when the set of layers (or order of layers) visible in the canvas changes.
QgsMapLayer * layer() const
void visibilityChanged(QgsLayerTreeNode *node)
Emitted when check state of a node within the tree has been changed.
void setLayers(const QList< QgsMapLayer *> &layers)
Sets the list of layers that should be shown in the canvas.
static QgsProject * instance()
Returns the QgsProject singleton instance.
Definition: qgsproject.cpp:379
void zoomToFullExtent()
Zoom to the full extent of all layers.
This class represents a coordinate reference system (CRS).
QList< QgsLayerTreeLayer * > findLayers() const
Find all layer nodes.
QgsLayerTreeLayer * findLayer(QgsMapLayer *layer) const
Find layer node representing the map layer.
void customPropertyChanged(QgsLayerTreeNode *node, const QString &key)
Emitted when a custom property of a node within the tree has been changed or removed.
QgsLayerTreeMapCanvasBridge(QgsLayerTree *root, QgsMapCanvas *canvas, QObject *parent=0)
Constructor: does not take ownership of the layer tree nor canvas.
Layer tree node points to a map layer.
bool isValid() const
Returns whether this CRS is correctly initialized and usable.