QGIS API Documentation 3.29.0-Master (8c80f25a4f)
qgsprevieweffect.cpp
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1/***************************************************************************
2 qgsprevieweffect.cpp
3 -------------------
4 begin : March 2014
5 copyright : (C) 2014 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
18#include <QPainter>
19#include "qgsprevieweffect.h"
20
21
23 : QGraphicsEffect( parent )
24 , mMode( PreviewGrayscale )
25{
26 //effect is disabled by default
27 setEnabled( false );
28}
29
31{
32 mMode = mode;
33 update();
34}
35
36void QgsPreviewEffect::draw( QPainter *painter )
37{
38 QPoint offset;
39 QPixmap pixmap;
40
41 if ( sourceIsPixmap() )
42 {
43 // No point in drawing in device coordinates (pixmap will be scaled anyways).
44 pixmap = sourcePixmap( Qt::LogicalCoordinates, &offset );
45 }
46 else
47 {
48 // Draw pixmap in device coordinates to avoid pixmap scaling;
49 pixmap = sourcePixmap( Qt::DeviceCoordinates, &offset );
50 painter->setWorldTransform( QTransform() );
51 }
52
53 QImage image = pixmap.toImage();
54
55 switch ( mMode )
56 {
58 {
59 const QImage bwImage = image.convertToFormat( QImage::Format_Mono );
60 painter->drawImage( offset, bwImage );
61 break;
62 }
67 {
68 QRgb *line = nullptr;
69
70 for ( int y = 0; y < image.height(); y++ )
71 {
72 line = ( QRgb * )image.scanLine( y );
73 for ( int x = 0; x < image.width(); x++ )
74 {
75 line[x] = simulateColorBlindness( line[x], mMode );
76 }
77 }
78
79 painter->drawImage( offset, image );
80 break;
81 }
82 }
83
84}
85
86QRgb QgsPreviewEffect::simulateColorBlindness( QRgb &originalColor, QgsPreviewEffect::PreviewMode mode )
87{
88 int red = qRed( originalColor );
89 int green = qGreen( originalColor );
90 int blue = qBlue( originalColor );
91
92 int r = red;
93 int g = green;
94 int b = blue;
95
96 //simulate color blindness
97 //matrix values taken from Machado et al. (2009), https://doi.org/10.1109/TVCG.2009.113:
98 //https://www.inf.ufrgs.br/~oliveira/pubs_files/CVD_Simulation/CVD_Simulation.html
99 switch ( mode )
100 {
101 case PreviewGrayscale:
102 simulateGrayscale( r, g, b, red, green, blue );
103 break;
104 case PreviewProtanope:
105 simulateProtanope( r, g, b, red, green, blue );
106 break;
108 simulateDeuteranope( r, g, b, red, green, blue );
109 break;
110 case PreviewTritanope:
111 simulateTritanope( r, g, b, red, green, blue );
112 break;
113 default:
114 break;
115 }
116
117 //restrict values to 0-255
118 r = std::max( std::min( 255, r ), 0 );
119 g = std::max( std::min( 255, g ), 0 );
120 b = std::max( std::min( 255, b ), 0 );
121
122 return qRgb( r, g, b );
123}
124
125void QgsPreviewEffect::simulateGrayscale( int &r, int &g, int &b, int &red, int &green, int &blue )
126{
127 r = ( 0.2126 * red ) + ( 0.7152 * green ) + ( 0.0722 * blue );
128 g = r;
129 b = r;
130}
131
132void QgsPreviewEffect::simulateProtanope( int &r, int &g, int &b, int &red, int &green, int &blue )
133{
134 r = ( 0.152286 * red ) + ( 1.052583 * green ) + ( -0.204868 * blue );
135 g = ( 0.114503 * red ) + ( 0.786281 * green ) + ( 0.099216 * blue );
136 b = ( -0.003882 * red ) + ( -0.048116 * green ) + ( 1.051998 * blue );
137}
138
139void QgsPreviewEffect::simulateDeuteranope( int &r, int &g, int &b, int &red, int &green, int &blue )
140{
141 r = ( 0.367322 * red ) + ( 0.860646 * green ) + ( -0.227968 * blue );
142 g = ( 0.280085 * red ) + ( 0.672501 * green ) + ( 0.047413 * blue );
143 b = ( -0.011820 * red ) + ( 0.042940 * green ) + ( 0.968881 * blue );
144}
145
146void QgsPreviewEffect::simulateTritanope( int &r, int &g, int &b, int &red, int &green, int &blue )
147{
148 r = ( 1.255528 * red ) + ( -0.076749 * green ) + ( -0.178779 * blue );
149 g = ( -0.078411 * red ) + ( 0.930809 * green ) + ( 0.147602 * blue );
150 b = ( 0.004733 * red ) + ( 0.691367 * green ) + ( 0.303900 * blue );
151}
void draw(QPainter *painter) override
void setMode(PreviewMode mode)
Sets the mode for the preview effect, which controls how the effect modifies a widgets appearance.
PreviewMode mode() const
Returns the mode used for the preview effect.
QgsPreviewEffect(QObject *parent)