Transfer paint event to QScrollarea

[vinithr]

Hi all,

I am trying to draw a graph in QT application using a paintevent.

I could be able to draw in the wisget. But i need to transfer that paintevent to QScroll Area that is present in MainWindow.h.

Could anyone help me to sort out thius issue.Here i am pasting my code for your reference.


main.cpp


#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();
}


mainwindow.cpp


#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtGui>
#include<QPainter>


#define XAXISLABEL 340
#define XAXISSTARTWIDTH 100 //start width from the left corner
#define XAXISSTDWIDTH 40 //width betwen each label in the x axis
#define XAXISCORRECTION 20 //correction value for the xaxis lable display


MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::paintEvent(QPaintEvent * /*event*/)
{
QPainter painter(this);
// painter.translate(scrollArea);
// painter.setWindow(scrollArea);
int i=1000;

const int start = 100;
const int act_unit_w = 1;
const int act_unit_h = 10;

QFontMetrics metrics(font());
QColor color;

QBrush Brush1(Qt::red,Qt::SolidPattern);
QBrush Brush2(Qt::green,Qt::SolidPattern);

int ReferenceValue[22]={12,44,55,66,77,88,99,11,10,13,78,87,66,56,76,67, 89,67,56,67,67};
int PCValue[22]={12,44,40,20,77,88,32,11,10,13,78,87,66,56,76,67, 89,67,56,67,67};

int myvalue=20;
int refvalue=40;
int MyTemp1=25;
int MyTemp2=40;

int width=15;
int height=3;

for(int k=0;k<21;k++)
{
myvalue=ReferenceValue[k];
painter.fillRect((XAXISSTARTWIDTH+MyTemp1),(320-(myvalue*height)),width,(myvalue*height),Brush1);
MyTemp1=MyTemp1+40;

}

for(int m=0;m<21;m++)
{
refvalue=PCValue[m];
painter.fillRect((XAXISSTARTWIDTH+MyTemp2),(320-(refvalue*height)),width,(refvalue*height),Brush2) ;
MyTemp2=MyTemp2+40;

}
painter.save();
// painter.setBrush(badBrush);
painter.setPen(QColor(Qt::black));


//fill x axis
for( int j=start; j< 1000+start ; j += act_unit_w*XAXISSTDWIDTH ){
painter.drawLine(j,320,j,325);
// painter.drawText(j,340,QString::number(j-start,10));
}

//X Axis text

painter.drawText((XAXISSTARTWIDTH +0)-XAXISCORRECTION,XAXISLABEL,QString("0"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *1))-XAXISCORRECTION,XAXISLABEL,QString("3-4"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *2))-XAXISCORRECTION,XAXISLABEL,QString("4-5"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *3))-XAXISCORRECTION,XAXISLABEL,QString("5-6"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *4))-XAXISCORRECTION,XAXISLABEL,QString("6-7"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *5))-XAXISCORRECTION,XAXISLABEL,QString("7-8"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *6))-XAXISCORRECTION,XAXISLABEL,QString("8-9"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *7))-XAXISCORRECTION,XAXISLABEL,QString("9-10"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *8))-XAXISCORRECTION,XAXISLABEL,QString("10-11"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *9))-XAXISCORRECTION,XAXISLABEL,QString("11-12"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *10))-XAXISCORRECTION,XAXISLABEL,QString("12-13"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *11))-XAXISCORRECTION,XAXISLABEL,QString("13-14"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *12))-XAXISCORRECTION,XAXISLABEL,QString("14-15"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *13))-XAXISCORRECTION,XAXISLABEL,QString("15-16"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *14))-XAXISCORRECTION,XAXISLABEL,QString("16-17"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *15))-XAXISCORRECTION,XAXISLABEL,QString("17-18"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *16))-XAXISCORRECTION,XAXISLABEL,QString("18-19"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *17))-XAXISCORRECTION,XAXISLABEL,QString("19-XAXISCORRECTION"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *18))-XAXISCORRECTION,XAXISLABEL,QString("XAXISCORRECTION-21"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *19))-XAXISCORRECTION,XAXISLABEL,QString("21-22"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *20))-XAXISCORRECTION,XAXISLABEL,QString("22-23"));
painter.drawText((XAXISSTARTWIDTH +(XAXISSTDWIDTH *21))-XAXISCORRECTION,XAXISLABEL,QString("23-24"));

//Y axis text
painter.drawText(50,20,QString("100"));
painter.drawText(50,80,QString("80"));
painter.drawText(50,140,QString("60"));
painter.drawText(50,200,QString("40"));
painter.drawText(50,260,QString("20"));
painter.drawLine(start,20,1000,20);
painter.drawLine(start,80,1000,80);
painter.drawLine(start,140,1000,140);
painter.drawLine(start,200,1000,200);
painter.drawLine(start,260,1000,260);
// painter.drawText(0,0,640,50,Qt::AlignCenter,QStrin g("Power Curve"));
painter.drawLine(start,20,start,320);
painter.drawLine(start,320,1000,320);

painter.restore();
}



mainwindow.h


#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QScrollArea>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:

protected:
void paintEvent(QPaintEvent *event);
QSize size;
//void timerEvent(QTimerEvent *event);

public:
QScrollArea *scrollArea;


private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H



mainwindow.ui


<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>1024</width>
<height>600</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QScrollArea" name="scrollArea">
<property name="geometry">
<rect>
<x>60</x>
<y>60</y>
<width>451</width>
<height>291</height>
</rect>
</property>
<property name="minimumSize">
<size>
<width>451</width>
<height>291</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>451</width>
<height>291</height>
</size>
</property>
<property name="widgetResizable">
<bool>true</bool>
</property>
<widget class="QWidget" name="scrollAreaWidgetContents">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>449</width>
<height>289</height>
</rect>
</property>
</widget>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>1024</width>
<height>25</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>



Thanks in Advance.

Regards
Vinithr

[ChrisW67]

Create a custom widget that has your painting code and make an instance of that widget the central widget of a generic QMainWindow.

[BalaQT]

If u r trying to create graphs , u can use qwt
qwt.sourceforge.net

hope it helps
Bala