QGIS API Documentation  3.6.0-Noosa (5873452)
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  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 }
void setForceVectorOutput(bool force)
A rectangle specified with double values.
Definition: qgsrectangle.h:41
QgsRectangle rect() const
returns canvas item rectangle in map units
QgsPointXY toMapCoordinates(QPoint point) const
transformation from screen coordinates to map coordinates
double y
Definition: qgspointxy.h:48
A class to represent a 2D point.
Definition: qgspointxy.h:43
double rotation() const
Gets the current map canvas rotation in clockwise degrees.
void setRendererScale(double scale)
Sets the renderer map scale.
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:73
The QgsMapSettings class contains configuration for rendering of the map.
void transformInPlace(double &x, double &y) const
Transform device coordinates to map coordinates.
~QgsMapCanvasItem() override
QSizeF mItemSize
cached size of the item (to return in boundingRect())
Perform transforms between map coordinates and device coordinates.
Definition: qgsmaptopixel.h:37
QRectF boundingRect() const override
void setScaleFactor(double factor)
Sets the scaling factor for the render to convert painter units to physical sizes.
bool isEmpty() const
Returns true if the rectangle is empty.
Definition: qgsrectangle.h:426
double width() const
Returns the width of the rectangle.
Definition: qgsrectangle.h:202
void setRect(const QgsRectangle &r, bool resetRotation=true)
sets canvas item rectangle in map units
QgsRectangle mRect
cached canvas item rectangle in map coordinates encodes position (xmin,ymax) and size (width/height) ...
void setPainter(QPainter *p)
Sets the destination QPainter for the render operation.
double mapUnitsPerPixel() const
Returns current map units per pixel.
double x
Definition: qgspointxy.h:47
QgsMapCanvasItem(QgsMapCanvas *mapCanvas)
protected constructor: cannot be constructed directly
void updateCanvas()
schedules map canvas for repaint
double scale() const
Returns the last reported scale of the canvas.
virtual void paint(QPainter *painter)=0
function to be implemented by derived classes
const QgsMapSettings & mapSettings() const
Gets access to properties used for map rendering.
double outputDpi() const
Returns DPI used for conversion between real world units (e.g.
Contains information about the context of a rendering operation.
bool antiAliasingEnabled() const
true if antialising is enabled
Definition: qgsmapcanvas.h:469
QgsMapCanvas * mMapCanvas
pointer to map canvas
double xMinimum() const
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:167
const QgsMapToPixel * getCoordinateTransform()
Gets the current coordinate transform.
double yMaximum() const
Returns the y maximum value (top side of rectangle).
Definition: qgsrectangle.h:172
QPointF toCanvasCoordinates(const QgsPointXY &point) const
transformation from map coordinates to screen coordinates
virtual void updatePosition()
called on changed extent or resize event to update position of the item
QgsPointXY toMapCoordinates(int x, int y) const
Transform device coordinates to map (world) coordinates.
double height() const
Returns the height of the rectangle.
Definition: qgsrectangle.h:209
bool setRenderContextVariables(QPainter *p, QgsRenderContext &context) const
Sets render context parameters.