QGIS API Documentation  3.21.0-Master (5b68dc587e)
qgsrasterbandcombobox.cpp
Go to the documentation of this file.
1 /***************************************************************************
2  qgsrasterbandcombobox.cpp
3  -------------------------
4  begin : May 2017
5  copyright : (C) 2017 by Nyall Dawson
6  email : nyall dot dawson 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 "qgsrasterbandcombobox.h"
17 #include "qgsrasterlayer.h"
18 #include "qgsrasterdataprovider.h"
19 
21  : QComboBox( parent )
22  , mNotSetString( tr( "Not set" ) )
23 {
24  connect( this, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, [ = ]
25  {
26  if ( mLayer && mLayer->isValid() )
27  {
28  const int newBand = currentIndex() >= 0 ? currentData().toInt() : -1 ;
29  if ( newBand != mPrevBand )
30  {
31  emit bandChanged( currentIndex() >= 0 ? currentData().toInt() : -1 );
32  mPrevBand = newBand;
33  }
34  }
35  } );
36 
37  connect( this, &QComboBox::currentTextChanged, this, [ = ]( const QString & value )
38  {
39  if ( !mLayer || !mLayer->isValid() )
40  {
41  bool ok = false;
42  const int band = value.toInt( &ok );
43  if ( ok && band != mPrevBand )
44  {
45  emit bandChanged( band );
46  mPrevBand = band;
47  }
48  else if ( mShowNotSet && mPrevBand != -1 )
49  {
50  emit bandChanged( -1 );
51  mPrevBand = -1;
52  }
53  }
54  } );
55 
56  // default to editable, until a layer is set
57  setEditable( true );
58 }
59 
61 {
62  return mLayer;
63 }
64 
66 {
67  if ( !mLayer || !mLayer->dataProvider() || !mLayer->isValid() )
68  {
69  bool ok = false;
70  const int band = currentText().toInt( &ok );
71  if ( ok )
72  return band;
73  return -1;
74  }
75  else
76  {
77  if ( currentIndex() < 0 )
78  return -1;
79 
80  return currentData().toInt();
81  }
82 }
83 
85 {
86  const int oldBand = currentBand();
87 
88  QgsRasterLayer *rl = qobject_cast< QgsRasterLayer * >( layer );
89  mLayer = rl;
90 
91  blockSignals( true );
92  clear();
93 
94  if ( mShowNotSet )
95  addItem( mNotSetString, -1 );
96 
97  if ( mLayer )
98  {
99  QgsRasterDataProvider *provider = mLayer->dataProvider();
100  if ( provider && mLayer->isValid() )
101  {
102  setEditable( false );
103  //fill available bands into combo box
104  const int nBands = provider->bandCount();
105  for ( int i = 1; i <= nBands; ++i ) //band numbering seem to start at 1
106  {
107  addItem( displayBandName( provider, i ), i );
108  }
109  }
110  else
111  {
112  setEditable( true );
113  }
114  }
115  else
116  {
117  setEditable( true );
118  }
119 
120  if ( oldBand >= 0 )
121  setBand( oldBand );
122  else
123  setCurrentIndex( 0 );
124 
125  blockSignals( false );
126  const int newBand = currentBand();
127  //if ( newBand != oldBand )
128  // emit bandChanged( newBand );
129  mPrevBand = newBand;
130 }
131 
133 {
134  if ( !mLayer || !mLayer->dataProvider() || !mLayer->isValid() )
135  {
136  if ( band < 0 )
137  {
138  setCurrentIndex( -1 );
139  if ( mPrevBand != -1 )
140  emit bandChanged( -1 );
141  }
142  else
143  setCurrentText( QString::number( band ) );
144  }
145  else
146  {
147  setCurrentIndex( findData( band ) );
148  }
149  mPrevBand = band;
150 }
151 
153 {
154  return mShowNotSet;
155 }
156 
157 void QgsRasterBandComboBox::setShowNotSetOption( bool show, const QString &string )
158 {
159  mShowNotSet = show;
160  mNotSetString = string.isEmpty() ? tr( "Not set" ) : string;
161  setLayer( mLayer );
162 }
163 
165 {
166  if ( !provider )
167  return QString();
168 
169  return provider->displayBandName( band );
170 }
Base class for all map layer types.
Definition: qgsmaplayer.h:73
QgsRasterLayer * layer() const
Returns the layer currently associated with the combobox.
void bandChanged(int band)
Emitted when the currently selected band changes.
void setShowNotSetOption(bool show, const QString &string=QString())
Sets whether the combo box should show the "not set" option.
int currentBand() const
Returns the current band number selected in the combobox, or -1 if no band is selected.
QgsRasterBandComboBox(QWidget *parent=nullptr)
Constructor for QgsRasterBandComboBox.
void setLayer(QgsMapLayer *layer)
Sets the raster layer for which the bands are listed in the combobox.
static QString displayBandName(QgsRasterDataProvider *provider, int band)
Returns a user-friendly band name for the specified band.
bool isShowingNotSetOption() const
Returns true if the combo box is showing the "not set" option.
void setBand(int band)
Sets the current band number selected in the combobox.
Base class for raster data providers.
virtual int bandCount() const =0
Gets number of bands.
QString displayBandName(int bandNumber) const
Generates a friendly, descriptive name for the specified bandNumber.
Represents a raster layer.