QGIS API Documentation  3.8.0-Zanzibar (11aff65)
qgsgraduatedhistogramwidget.cpp
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1 /***************************************************************************
2  qgsgraduatedhistogramwidget.cpp
3  -------------------------------
4  begin : May 2015
5  copyright : (C) 2015 by Nyall Dawson
6  email : nyall dot dawson at gmail dot com
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 
21 #include "qgsapplication.h"
22 #include "qgsvectorlayer.h"
23 #include "qgsstatisticalsummary.h"
24 
25 #include <QSettings>
26 #include <QObject>
27 #include <QMouseEvent>
28 
29 // QWT Charting widget
30 #include <qwt_global.h>
31 #include <qwt_plot_canvas.h>
32 #include <qwt_plot.h>
33 #include <qwt_plot_curve.h>
34 #include <qwt_plot_grid.h>
35 #include <qwt_plot_marker.h>
36 #include <qwt_plot_picker.h>
37 #include <qwt_picker_machine.h>
38 #include <qwt_plot_layout.h>
39 #include <qwt_plot_renderer.h>
40 #include <qwt_plot_histogram.h>
41 
42 
44  : QgsHistogramWidget( parent )
45 {
46  //clear x axis title to make more room for graph
47  setXAxisTitle( QString() );
48 
49  mFilter = new QgsGraduatedHistogramEventFilter( mPlot );
50 
51  connect( mFilter, &QgsGraduatedHistogramEventFilter::mousePress, this, &QgsGraduatedHistogramWidget::mousePress );
52  connect( mFilter, &QgsGraduatedHistogramEventFilter::mouseRelease, this, &QgsGraduatedHistogramWidget::mouseRelease );
53 
54  mHistoPicker = new QwtPlotPicker( mPlot->canvas() );
55  mHistoPicker->setTrackerMode( QwtPicker::ActiveOnly );
56  mHistoPicker->setRubberBand( QwtPicker::VLineRubberBand );
57  mHistoPicker->setStateMachine( new QwtPickerDragPointMachine );
58 }
59 
61 {
62  mRenderer = renderer;
63 }
64 
66 {
67  if ( !mRenderer )
68  return;
69 
70  bool pickerEnabled = false;
71  if ( mRenderer->rangesOverlap() )
72  {
73  setToolTip( tr( "Ranges are overlapping and can't be edited by the histogram" ) );
75  }
76  else if ( mRenderer->rangesHaveGaps() )
77  {
78  setToolTip( tr( "Ranges have gaps and can't be edited by the histogram" ) );
80  }
81  else if ( mRenderer->ranges().isEmpty() )
82  {
83  setToolTip( QString() );
85  }
86  else
87  {
88  setToolTip( QString() );
89  setGraduatedRanges( mRenderer->ranges() );
90  pickerEnabled = true;
91  }
93 
94  // histo picker
95  mHistoPicker->setEnabled( pickerEnabled );
96  mFilter->blockSignals( !pickerEnabled );
97 }
98 
99 void QgsGraduatedHistogramWidget::mousePress( double value )
100 {
101  mPressedValue = value;
102 
103  int closestRangeIndex = 0;
104  int minPixelDistance = 9999;
105  findClosestRange( mPressedValue, closestRangeIndex, minPixelDistance );
106 
107  if ( minPixelDistance <= 6 )
108  {
109  //moving a break, so hide the break line
110  mRangeMarkers.at( closestRangeIndex )->hide();
111  mPlot->replot();
112  }
113 }
114 
115 void QgsGraduatedHistogramWidget::mouseRelease( double value )
116 {
117  int closestRangeIndex = 0;
118  int minPixelDistance = 9999;
119  findClosestRange( mPressedValue, closestRangeIndex, minPixelDistance );
120 
121  if ( minPixelDistance <= 6 )
122  {
123  //do a sanity check - don't allow users to drag a break line
124  //into the middle of a different range. Doing so causes overlap
125  //of the ranges
126 
127  //new value needs to be within range covered by closestRangeIndex or
128  //closestRangeIndex + 1
129  if ( value <= mRenderer->ranges().at( closestRangeIndex ).lowerValue() ||
130  value >= mRenderer->ranges().at( closestRangeIndex + 1 ).upperValue() )
131  {
132  refresh();
133  return;
134  }
135 
136  mRenderer->updateRangeUpperValue( closestRangeIndex, value );
137  mRenderer->updateRangeLowerValue( closestRangeIndex + 1, value );
138  emit rangesModified( false );
139  }
140  else
141  {
142  //if distance from markers is too big, add a break
143  mRenderer->addBreak( value );
144  emit rangesModified( true );
145  }
146 
147  refresh();
148 }
149 
150 void QgsGraduatedHistogramWidget::findClosestRange( double value, int &closestRangeIndex, int &pixelDistance ) const
151 {
152  const QgsRangeList &ranges = mRenderer->ranges();
153 
154  double minDistance = std::numeric_limits<double>::max();
155  int pressedPixel = mPlot->canvasMap( QwtPlot::xBottom ).transform( value );
156  for ( int i = 0; i < ranges.count() - 1; ++i )
157  {
158  if ( std::fabs( mPressedValue - ranges.at( i ).upperValue() ) < minDistance )
159  {
160  closestRangeIndex = i;
161  minDistance = std::fabs( mPressedValue - ranges.at( i ).upperValue() );
162  pixelDistance = std::fabs( pressedPixel - mPlot->canvasMap( QwtPlot::xBottom ).transform( ranges.at( i ).upperValue() ) );
163  }
164  }
165 }
166 
168 
169 QgsGraduatedHistogramEventFilter::QgsGraduatedHistogramEventFilter( QwtPlot *plot )
170  : QObject( plot )
171  , mPlot( plot )
172 {
173  mPlot->canvas()->installEventFilter( this );
174 }
175 
176 bool QgsGraduatedHistogramEventFilter::eventFilter( QObject *object, QEvent *event )
177 {
178  if ( !mPlot->isEnabled() )
179  return QObject::eventFilter( object, event );
180 
181  switch ( event->type() )
182  {
183  case QEvent::MouseButtonPress:
184  {
185  const QMouseEvent *mouseEvent = static_cast<QMouseEvent * >( event );
186  if ( mouseEvent->button() == Qt::LeftButton )
187  {
188  emit mousePress( posToValue( mouseEvent->pos() ) );
189  }
190  break;
191  }
192  case QEvent::MouseButtonRelease:
193  {
194  const QMouseEvent *mouseEvent = static_cast<QMouseEvent * >( event );
195  if ( mouseEvent->button() == Qt::LeftButton )
196  {
197  emit mouseRelease( posToValue( mouseEvent->pos() ) );
198  }
199  break;
200  }
201  default:
202  break;
203  }
204 
205  return QObject::eventFilter( object, event );
206 }
207 
208 double QgsGraduatedHistogramEventFilter::posToValue( QPointF point ) const
209 {
210  if ( !mPlot )
211  return -99999999;
212 
213  return mPlot->canvasMap( QwtPlot::xBottom ).invTransform( point.x() );
214 }
QgsGraduatedHistogramWidget(QWidget *parent=nullptr)
QgsGraduatedHistogramWidget constructor.
bool updateRangeUpperValue(int rangeIndex, double value)
QList< QgsRendererRange > QgsRangeList
bool rangesOverlap() const
Tests whether classes assigned to the renderer have ranges which overlap.
void addBreak(double breakValue, bool updateSymbols=true)
Add a breakpoint by splitting existing classes so that the specified value becomes a break between tw...
void rangesModified(bool rangesAdded)
Emitted when the user modifies the graduated ranges using the histogram widget.
bool rangesHaveGaps() const
Tests whether classes assigned to the renderer have gaps between the ranges.
void setGraduatedRanges(const QgsRangeList &ranges)
Sets the graduated ranges associated with the histogram.
bool updateRangeLowerValue(int rangeIndex, double value)
void setRenderer(QgsGraduatedSymbolRenderer *renderer)
Sets the QgsGraduatedSymbolRenderer renderer associated with the histogram.
void refresh()
Redraws the histogram.
void drawHistogram() override
Updates and redraws the histogram.
virtual void drawHistogram()
Updates and redraws the histogram.
Graphical histogram for displaying distributions of field values.
void setXAxisTitle(const QString &title)
Sets the title for the histogram&#39;s x-axis.
QList< QwtPlotMarker *> mRangeMarkers
const QgsRangeList & ranges() const