QGIS API Documentation  3.21.0-Master (5b68dc587e)
qgsmapcanvasitem.cpp
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1 /***************************************************************************
2  qgsmapcanvasitem.h - base class for map canvas items
3  ----------------------
4  begin : February 2006
5  copyright : (C) 2006 by Martin Dobias
6  email : wonder.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 
16 
17 #include "qgsmapcanvasitem.h"
18 #include "qgsmapcanvas.h"
19 #include "qgsmaptopixel.h"
20 #include "qgsrendercontext.h"
21 #include <QGraphicsScene>
22 #include <QRect>
23 #include <QPen>
24 #include <QBrush>
25 #include <QPainter>
26 #include "qgslogger.h"
27 
29  : mMapCanvas( mapCanvas )
30  , mRectRotation( 0.0 )
31  , mItemSize( 0, 0 )
32 {
33  Q_ASSERT( mapCanvas && mapCanvas->scene() );
34  mapCanvas->scene()->addItem( this );
35 }
36 
38 {
39  update(); // schedule redraw of canvas
40 }
41 
42 void QgsMapCanvasItem::paint( QPainter *painter,
43  const QStyleOptionGraphicsItem *option,
44  QWidget *widget )
45 {
46  Q_UNUSED( option )
47  Q_UNUSED( widget )
49  {
50  painter->setRenderHint( QPainter::Antialiasing );
51  }
52  paint( painter ); // call the derived item's drawing routines
53 }
54 
56 {
58 }
59 
60 
62 {
63  qreal x = point.x(), y = point.y();
65  return QPointF( x, y );
66 }
67 
69 {
70  return mRect;
71 }
72 
73 
74 void QgsMapCanvasItem::setRect( const QgsRectangle &rect, bool resetRotation )
75 {
76  mRect = rect;
77  //updatePosition();
78 
79  QRectF r; // empty rect by default
80  if ( !mRect.isEmpty() )
81  {
82  // rect encodes origin of the item (xMin,yMax from map to canvas units)
83  // and size (rect size / map units per pixel)
84  r.setTopLeft( toCanvasCoordinates( QPointF( mRect.xMinimum(), mRect.yMaximum() ) ) );
86  const double res = m2p->mapUnitsPerPixel();
87  r.setSize( QSizeF( mRect.width() / res, mRect.height() / res ) );
88  }
89 
90  // set position in canvas where the item will have coordinate (0,0)
91  prepareGeometryChange();
92  setPos( r.topLeft() );
93  mItemSize = QSizeF( r.width() + 2, r.height() + 2 );
94 
95  if ( resetRotation )
96  {
98  setRotation( 0 );
99  }
100 
101  // QgsDebugMsg(QString("[%1,%2]-[%3x%4]").arg((int) r.left()).arg((int) r.top()).arg((int) r.width()).arg((int) r.height()));
102 
103  update();
104 }
105 
107 {
108  return QRectF( QPointF( -1, -1 ), mItemSize );
109 }
110 
111 
113 {
114  update();
115  // porting: update below should not be needed anymore
116  //mMapCanvas->scene()->update(); //Contents();
117 }
118 
120 {
121  if ( !mMapCanvas || !p )
122  {
123  return false;
124  }
125  const QgsMapSettings &ms = mMapCanvas->mapSettings();
126 
127  context.setPainter( p );
128  context.setRendererScale( mMapCanvas->scale() );
129  context.setScaleFactor( ms.outputDpi() / 25.4 );
130 
131  context.setForceVectorOutput( true );
132  return true;
133 }
134 
136 {
137  // default implementation: recalculate position of the item
138  setRect( mRect, false );
139  setRotation( mMapCanvas->rotation() - mRectRotation );
140 }
QRectF boundingRect() const override
virtual void paint(QPainter *painter)=0
function to be implemented by derived classes
QSizeF mItemSize
cached size of the item (to return in boundingRect())
QgsRectangle rect() const
returns canvas item rectangle in map units
QgsRectangle mRect
cached canvas item rectangle in map coordinates encodes position (xmin,ymax) and size (width/height) ...
QPointF toCanvasCoordinates(const QgsPointXY &point) const
transformation from map coordinates to screen coordinates
QgsMapCanvas * mMapCanvas
pointer to map canvas
void setRect(const QgsRectangle &r, bool resetRotation=true)
sets canvas item rectangle in map units
QgsMapCanvasItem(QgsMapCanvas *mapCanvas)
protected constructor: cannot be constructed directly
void updateCanvas()
schedules map canvas for repaint
~QgsMapCanvasItem() override
bool setRenderContextVariables(QPainter *p, QgsRenderContext &context) const
Sets render context parameters.
virtual void updatePosition()
called on changed extent or resize event to update position of the item
QgsPointXY toMapCoordinates(QPoint point) const
transformation from screen coordinates to map coordinates
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:88
bool antiAliasingEnabled() const
true if antialiasing is enabled
double scale() const
Returns the last reported scale of the canvas.
double rotation() const
Gets the current map canvas rotation in clockwise degrees.
const QgsMapToPixel * getCoordinateTransform()
Gets the current coordinate transform.
const QgsMapSettings & mapSettings() const
Gets access to properties used for map rendering.
The QgsMapSettings class contains configuration for rendering of the map.
double outputDpi() const
Returns the DPI (dots per inch) used for conversion between real world units (e.g.
Perform transforms between map coordinates and device coordinates.
Definition: qgsmaptopixel.h:39
double mapUnitsPerPixel() const
Returns the current map units per pixel.
QgsPointXY toMapCoordinates(int x, int y) const
Transforms device coordinates to map (world) coordinates.
void transformInPlace(double &x, double &y) const
Transforms device coordinates to map coordinates.
A class to represent a 2D point.
Definition: qgspointxy.h:59
double y
Definition: qgspointxy.h:63
Q_GADGET double x
Definition: qgspointxy.h:62
A rectangle specified with double values.
Definition: qgsrectangle.h:42
double yMaximum() const SIP_HOLDGIL
Returns the y maximum value (top side of rectangle).
Definition: qgsrectangle.h:193
double xMinimum() const SIP_HOLDGIL
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:188
double height() const SIP_HOLDGIL
Returns the height of the rectangle.
Definition: qgsrectangle.h:230
double width() const SIP_HOLDGIL
Returns the width of the rectangle.
Definition: qgsrectangle.h:223
bool isEmpty() const
Returns true if the rectangle is empty.
Definition: qgsrectangle.h:469
Contains information about the context of a rendering operation.
void setForceVectorOutput(bool force)
Sets whether rendering operations should use vector operations instead of any faster raster shortcuts...
void setScaleFactor(double factor)
Sets the scaling factor for the render to convert painter units to physical sizes.
void setPainter(QPainter *p)
Sets the destination QPainter for the render operation.
void setRendererScale(double scale)
Sets the renderer map scale.