QGIS API Documentation  3.13.0-Master (5a3b1ced84)
qgsmapcanvasmap.cpp
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1 /***************************************************************************
2  qgsmapcanvasmap.cpp - draws the map in map canvas
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 #include "qgslogger.h"
17 #include "qgsmapcanvas.h"
18 #include "qgsmapcanvasmap.h"
19 #include "qgsmaprendererjob.h"
20 #include "qgsmapsettings.h"
21 #include "qgsmaplayer.h"
22 
23 #include <QPainter>
24 
26 
27 QgsMapCanvasMap::QgsMapCanvasMap( QgsMapCanvas *canvas )
28  : QgsMapCanvasItem( canvas )
29 {
30  setZValue( -10 );
31 }
32 
33 void QgsMapCanvasMap::setContent( const QImage &image, const QgsRectangle &rect )
34 {
35  mPreviewImages.clear();
36 
37  mImage = image;
38 
39  // For true retro fans: this is approximately how the graphics looked like in 1990
40  if ( mMapCanvas->property( "retro" ).toBool() )
41  mImage = mImage.scaled( mImage.width() / 3, mImage.height() / 3 )
42  .convertToFormat( QImage::Format_Indexed8, Qt::OrderedDither | Qt::OrderedAlphaDither );
43 
44  setRect( rect );
45 }
46 
47 void QgsMapCanvasMap::addPreviewImage( const QImage &image, const QgsRectangle &rect )
48 {
49  mPreviewImages.append( qMakePair( image, rect ) );
50  update();
51 }
52 
53 QRectF QgsMapCanvasMap::boundingRect() const
54 {
55  double width = mItemSize.width();
56  double height = mItemSize.height();
57 
58  return QRectF( -width, -height, 3 * width, 3 * height );
59 }
60 
61 void QgsMapCanvasMap::paint( QPainter *painter )
62 {
63  // setRect() makes the size +2 :-(
64  int w = std::round( mItemSize.width() ) - 2;
65  int h = std::round( mItemSize.height() ) - 2;
66 
67  bool scale = false;
68  if ( mImage.size() != QSize( w, h ) * mImage.devicePixelRatioF() )
69  {
70  QgsDebugMsgLevel( QStringLiteral( "map paint DIFFERENT SIZE: img %1,%2 item %3,%4" )
71  .arg( mImage.width() / mImage.devicePixelRatioF() )
72  .arg( mImage.height() / mImage.devicePixelRatioF() )
73  .arg( w ).arg( h ), 2 );
74  // This happens on zoom events when ::paint is called before
75  // the renderer has completed
76  scale = true;
77  }
78 
79  /*Offset between 0/0 and mRect.xMinimum/mRect.yMinimum.
80  We need to consider the offset, because mRect is not updated yet and there might be an offset*/
81  QgsPointXY pt = toMapCoordinates( QPoint( 0, 0 ) );
82  double offsetX = pt.x() - mRect.xMinimum();
83  double offsetY = pt.y() - mRect.yMaximum();
84 
85  //draw preview images first
86  QList< QPair< QImage, QgsRectangle > >::const_iterator imIt = mPreviewImages.constBegin();
87  for ( ; imIt != mPreviewImages.constEnd(); ++imIt )
88  {
89  QPointF ul = toCanvasCoordinates( QgsPoint( imIt->second.xMinimum() + offsetX, imIt->second.yMaximum() + offsetY ) );
90  QPointF lr = toCanvasCoordinates( QgsPoint( imIt->second.xMaximum() + offsetX, imIt->second.yMinimum() + offsetY ) );
91  painter->drawImage( QRectF( ul.x(), ul.y(), lr.x() - ul.x(), lr.y() - ul.y() ), imIt->first, QRect( 0, 0, imIt->first.width(), imIt->first.height() ) );
92  }
93 
94  if ( scale )
95  painter->drawImage( QRect( 0, 0, w, h ), mImage );
96  else
97  painter->drawImage( 0, 0, mImage );
98 
99  // For debugging:
100 #if 0
101  QRectF br = boundingRect();
102  QPointF c = br.center();
103  double rad = std::max( br.width(), br.height() ) / 10;
104  painter->drawRoundedRect( br, rad, rad );
105  painter->drawLine( QLineF( 0, 0, br.width(), br.height() ) );
106  painter->drawLine( QLineF( br.width(), 0, 0, br.height() ) );
107 
108  double nw = br.width() * 0.5;
109  double nh = br.height() * 0.5;
110  br = QRectF( c - QPointF( nw / 2, nh / 2 ), QSize( nw, nh ) );
111  painter->drawRoundedRect( br, rad, rad );
112 
113  nw = br.width() * 0.5;
114  nh = br.height() * 0.5;
115  br = QRectF( c - QPointF( nw / 2, nh / 2 ), QSize( nw, nh ) );
116  painter->drawRoundedRect( br, rad, rad );
117 #endif
118 }
119 
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
An abstract class for items that can be placed on the map canvas.
Map canvas is a class for displaying all GIS data types on a canvas.
Definition: qgsmapcanvas.h:78
As part of the API refactoring and improvements which landed in the Processing API was substantially reworked from the x version This was done in order to allow much of the underlying Processing framework to be ported into c
QSizeF mItemSize
cached size of the item (to return in boundingRect())
QRectF boundingRect() const override
#define QgsDebugMsgLevel(str, level)
Definition: qgslogger.h:39
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) ...
Point geometry type, with support for z-dimension and m-values.
Definition: qgspoint.h:37
double x
Definition: qgspointxy.h:47
QgsMapCanvas * mMapCanvas
pointer to map canvas
double xMinimum() const
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:167
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