QGIS API Documentation  3.0.2-Girona (307d082)
qgsmaptoolextent.cpp
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1 /***************************************************************************
2  qgsmaptoolextent.h - map tool that emits an extent
3  ---------------------
4  begin : July 2017
5  copyright : (C) 2017 by Mathieu Pellerin
6  email : nirvn dot asia 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 "qgsmaptoolextent.h"
17 #include "qgsmapcanvas.h"
18 #include "qgswkbtypes.h"
19 
20 #include <QMouseEvent>
21 
22 
24  : QgsMapTool( canvas )
25 {
26  mRubberBand.reset( new QgsRubberBand( canvas, QgsWkbTypes::PolygonGeometry ) );
27 }
28 
30 {
32 }
33 
35 {
36  mRubberBand->reset( QgsWkbTypes::PolygonGeometry );
37 
39 }
40 
42 {
43  if ( !mDraw )
44  return;
45 
46 
47  QgsPointXY p = toMapCoordinates( e->pos() );
48  if ( mRatio.width() > 0 && mRatio.height() > 0 )
49  {
50  double width = std::fabs( p.x() - mStartPoint.x() );
51  double height = width * ( mRatio.width() / mRatio.height() );
52  if ( p.y() - mStartPoint.y() < 0 )
53  height *= -1;
54  p.setY( mStartPoint.y() + height );
55  }
56 
57  mEndPoint = toMapCoordinates( e->pos() );
58  calculateEndPoint( mEndPoint );
59  drawExtent();
60 }
61 
63 {
64  mStartPoint = toMapCoordinates( e->pos() );
65  mEndPoint = mStartPoint;
66  drawExtent();
67 
68  mDraw = true;
69 }
70 
72 {
73  if ( !mDraw )
74  return;
75 
76  mEndPoint = toMapCoordinates( e->pos() );
77  calculateEndPoint( mEndPoint );
78  drawExtent();
79 
80  emit extentChanged( extent() );
81 
82  mDraw = false;
83 }
84 
86 {
87  if ( mStartPoint.x() != mEndPoint.x() && mStartPoint.y() != mEndPoint.y() )
88  {
89  return QgsRectangle( mStartPoint, mEndPoint );
90  }
91  else
92  {
93  return QgsRectangle();
94  }
95 }
96 
97 void QgsMapToolExtent::calculateEndPoint( QgsPointXY &point )
98 {
99  if ( mRatio.width() > 0 && mRatio.height() > 0 )
100  {
101  double width = std::fabs( point.x() - mStartPoint.x() );
102  double height = width * mRatio.height() / mRatio.width();
103  if ( point.y() - mStartPoint.y() < 0 )
104  height *= -1;
105  point.setY( mStartPoint.y() + height );
106  }
107 }
108 
109 void QgsMapToolExtent::drawExtent()
110 {
111  if ( qgsDoubleNear( mStartPoint.x(), mEndPoint.x() ) && qgsDoubleNear( mStartPoint.y(), mEndPoint.y() ) )
112  return;
113 
114  mRubberBand->reset( QgsWkbTypes::PolygonGeometry );
115 
116  QgsRectangle rect( mStartPoint, mEndPoint );
117 
118  mRubberBand->reset( QgsWkbTypes::PolygonGeometry );
119  mRubberBand->addPoint( QgsPointXY( rect.xMinimum(), rect.yMinimum() ), false );
120  mRubberBand->addPoint( QgsPointXY( rect.xMaximum(), rect.yMinimum() ), false );
121  mRubberBand->addPoint( QgsPointXY( rect.xMaximum(), rect.yMaximum() ), false );
122  mRubberBand->addPoint( QgsPointXY( rect.xMinimum(), rect.yMaximum() ), true );
123 
124  mRubberBand->show();
125 }
A rectangle specified with double values.
Definition: qgsrectangle.h:39
void canvasReleaseEvent(QgsMapMouseEvent *e) override
Mouse release event for overriding. Default implementation does nothing.
double y
Definition: qgspointxy.h:48
A class to represent a 2D point.
Definition: qgspointxy.h:43
A QgsMapMouseEvent is the result of a user interaction with the mouse on a QgsMapCanvas.
QgsPointXY toMapCoordinates(QPoint point)
transformation from screen coordinates to map coordinates
Definition: qgsmaptool.cpp:40
QgsMapToolExtent(QgsMapCanvas *canvas)
constructor
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:74
bool qgsDoubleNear(double a, double b, double epsilon=4 *DBL_EPSILON)
Compare two doubles (but allow some difference)
Definition: qgis.h:251
virtual void activate()
called when set as currently active map tool
Definition: qgsmaptool.cpp:81
void canvasPressEvent(QgsMapMouseEvent *e) override
Mouse press event for overriding. Default implementation does nothing.
A class for drawing transient features (e.g.
Definition: qgsrubberband.h:37
void extentChanged(const QgsRectangle &extent)
signal emitted on extent change
void setY(double y)
Sets the y value of the point.
Definition: qgspointxy.h:113
QgsRectangle extent() const
Returns the current extent drawn onto the canvas.
virtual void deactivate()
called when map tool is being deactivated
Definition: qgsmaptool.cpp:97
double x
Definition: qgspointxy.h:47
double yMinimum() const
Returns the y minimum value (bottom side of rectangle).
Definition: qgsrectangle.h:130
double xMaximum() const
Returns the x maximum value (right side of rectangle).
Definition: qgsrectangle.h:115
void activate() override
called when set as currently active map tool
Abstract base class for all map tools.
Definition: qgsmaptool.h:63
void deactivate() override
called when map tool is being deactivated
double xMinimum() const
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:120
double yMaximum() const
Returns the y maximum value (top side of rectangle).
Definition: qgsrectangle.h:125
void canvasMoveEvent(QgsMapMouseEvent *e) override
Mouse move event for overriding. Default implementation does nothing.