how to draw a line over a frame?

[vinayaka]

Hai,
I am doing a project which needs a Qpainter to draw line but Qpainter donot work when we apply a style sheet to the frame where we have to draw the line

[stampede]

This works ok:

class Frame : public QFrame{
	Q_OBJECT
public:
	Frame( QWidget * parent = NULL ) : QFrame(parent){
		setStyleSheet( "Frame{ background: blue }" );
	}
protected:
	void paintEvent( QPaintEvent * event ){
		QFrame::paintEvent(event);
		QPainter p(this);
		p.drawLine( rect().topLeft(), rect().bottomRight() );
		p.drawText( rect().center(), "works!" );
	}
};

class Frame : public QFrame{
	Q_OBJECT
public:
	Frame( QWidget * parent = NULL ) : QFrame(parent){
		setStyleSheet( "Frame{ background: blue }" );
	}
protected:
	void paintEvent( QPaintEvent * event ){
		QFrame::paintEvent(event);
		QPainter p(this);
		p.drawLine( rect().topLeft(), rect().bottomRight() );
		p.drawText( rect().center(), "works!" );
	}
};

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[athulms]

can you provide me with an example. pls

[vishnu717]

Since iam using the form window , i cannot apply this code , please give me an Qt example of an frame with Style sheet(background image) and Qpainter drawing lines on it

[vinayaka]

thanx for your help but it doesnt work and gives errors while we run it. can you please give some more details

[ChrisW67]

You only have to change one line... clearly too hard:

#include <QtGui>
#include <QDebug>
 
class Frame : public QFrame{
    Q_OBJECT
public:
    Frame( QWidget * parent = NULL ) : QFrame(parent){
        // setStyleSheet( "Frame{ background: blue }" );
        setStyleSheet( "Frame{ background-image: url(plasma.png); }" );
    }
protected:
    void paintEvent( QPaintEvent * event ){
        QFrame::paintEvent(event);
        QPainter p(this);
        p.drawLine( rect().topLeft(), rect().bottomRight() );
        p.drawText( rect().center(), "works!" );
    }
};
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
 
    Frame m;
    m.show();
    return app.exec();
}
#include "main.moc"

#include <QtGui>
#include <QDebug>

class Frame : public QFrame{
    Q_OBJECT
public:
    Frame( QWidget * parent = NULL ) : QFrame(parent){
        // setStyleSheet( "Frame{ background: blue }" );
        setStyleSheet( "Frame{ background-image: url(plasma.png); }" );
    }
protected:
    void paintEvent( QPaintEvent * event ){
        QFrame::paintEvent(event);
        QPainter p(this);
        p.drawLine( rect().topLeft(), rect().bottomRight() );
        p.drawText( rect().center(), "works!" );
    }
};

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

    Frame m;
    m.show();
    return app.exec();
}
#include "main.moc"

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and it looks like:
simple_example.jpg
with a 64x64 tile background.


If you do not share the errors then you cannot expect corrections.

[wysota]

Since iam using the form window , i cannot apply this code

Why is that?

[stampede]

can you provide me with an example. pls

I already did.

thanx for your help but it doesnt work and gives errors while we run it. can you please give some more details

What errors ? It seems to work ok for ChrisW67.

[athulms]

in my progrm i am using 4frames(UI). I use show/hide frames using buttons. I have two draw a line in the 3rd frame. I have used the code

void MainWindow::paintEvent(QPaintEvent *e)
{
QPainter painter(this);
QPen linepen(Qt::red);
linepen.setWidth(25);
linepen.setCapStyle(Qt::RoundCap);
painter.setRenderHint(QPainter::Antialiasing,true);
painter.setPen(linepen);
painter.drawLine(point,point2);
}

void MainWindow::paintEvent(QPaintEvent *e)
{
QPainter painter(this);
QPen linepen(Qt::red);
linepen.setWidth(25);
linepen.setCapStyle(Qt::RoundCap);
painter.setRenderHint(QPainter::Antialiasing,true);
painter.setPen(linepen);
painter.drawLine(point,point2);
}

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since i have used the painter(this) the drawing is done on the main window so i cannot see the line on the frame. since frames(with background images) are placed over the main window.


Now i try to use painter(ui->frame3)

But it doesn't work. pls help me, thanks in advance

[stampede]

Asked here already. What part of the sample code you don't understand ?

[ChrisW67]

The (default) painting of the child will happen after the painting of the parent. If you override the paint event of the parent then why do you expect that the painting behaviour of a child widget will be changed? You want to override the paint event of the child widget.