Colour bars/Display: Difference between revisions

=={{header|C++}}==

using Qt 4.6

<PRE>file colorbars.h</PRE>

<lang C++>#ifndef MYWIDGET_H

#define MYWIDGET_H

#include <QWidget>

class QPaintEvent ;

class MyWidget : public QWidget {

public :

MyWidget( ) ;

protected :

void paintEvent( QPaintEvent * ) ;

private :

int width ;

int height ;

const int colornumber ;

} ;

#endif</lang>

<PRE>file colorbars.cpp</PRE>

<lang C++>#include <QtGui>

#include "colorbars.h"

MyWidget::MyWidget( ) :

width( 640 ) ,

height( 240 ) ,

colornumber( 8 ) {

setGeometry( 0, 0 , width , height ) ;

}

void MyWidget::paintEvent ( QPaintEvent * ) {

int rgbtriplets[ ] = { 0 , 0 , 0 , 255 , 0 , 0 , 0 , 255 , 0 ,

0 , 0 , 255 , 255 , 0 , 255 , 0 , 255 , 255 , 255 , 255 , 0 ,

255 , 255 , 255 } ;

QPainter myPaint( this ) ;

int rectwidth = width / colornumber ; //width of one rectangle

int xstart = 1 ; //x coordinate of the first rectangle

int offset = -1 ; //to allow for ++offset to define the red value even in the first run of the loop below

for ( int i = 0 ; i < colornumber ; i++ ) {

QColor rectColor ;

rectColor.setRed( rgbtriplets[ ++offset ] ) ;

rectColor.setGreen( rgbtriplets[ ++offset ] ) ;

rectColor.setBlue( rgbtriplets[ ++offset ] ) ;

myPaint.fillRect( xstart , 0 , rectwidth , height - 1 , rectColor ) ;

xstart += rectwidth + 1 ;

}

}</lang>

<PRE>file main.cpp</PRE>

<lang C++>#include <QApplication>

#include "colorbars.h"

int main( int argc, char * argv[ ] ) {

QApplication app( argc , argv ) ;

MyWidget window ;

window.setWindowTitle( QApplication::translate( "colorslides" , "color slides demonstration" ) ) ;

window.show( ) ;

return app.exec( ) ;

}</lang>