Drawing line on table

[kocakden]

Hi folks,
i just need to draw a line between one cell to an another(they do not have to be in the same row) on a table. I'm using Qt 4.3.4 for windows. I created the table and the cells. I thought that if i can get the coordinate of the cells i can draw the line but i couldn't find the function for it. Can anyone help me?

[wysota]

QAbstractItemView::visualRect()

[kocakden]

Thanks for quick reply. I read what you sent but i couldn't find out what to do. Can you explain a little bit more?

[wysota]

The method returns coordinates of an item you give it as its argument. I think that's what you wanted, right? Then you could do something like:

QModelIndex from = ...
QModelIndex to = ...
painter.drawLine(visualRect(from).center(), visualRect(to).center());

QModelIndex from = ...
QModelIndex to = ...
painter.drawLine(visualRect(from).center(), visualRect(to).center());

To copy to clipboard, switch view to plain text mode 

[kocakden]

Thanks again but i couldn't do it again. I found a different way to get the coordinates of cells. Here is my codes:

draw.h:

#ifndef DRAW_H
#define DRAW_H
 
#include <QWidget>
#include<QTableWidget>
 
class Draw : public QTableWidget
{
	Q_OBJECT
public:
	Draw(QWidget *parent = 0);
public slots:
	void d_drawline();
};
 
 
#endif

#ifndef DRAW_H
#define DRAW_H

#include <QWidget>
#include<QTableWidget>

class Draw : public QTableWidget
{
	Q_OBJECT
public:
	Draw(QWidget *parent = 0);
public slots:
	void d_drawline();
};


#endif

To copy to clipboard, switch view to plain text mode 

draw.cpp:

#include <QTableWidget>
#include <QTableWidgetItem>
#include <QPainter>
#include <QModelIndex>
#include <QAbstractItemView>
 
 
#include "draw.h"
 
Draw::Draw(QWidget *parent)	
{
	setRowCount(4);
	setColumnCount(4);
	this->setGeometry(0, 0, 500, 500);
}
 
void Draw::d_drawline()
{	
	int x_from = columnViewportPosition(1);
	int y_from  = rowViewportPosition(1);
	int x_to = columnViewportPosition(3);
	int y_to = rowViewportPosition(3);
 
	QPainter painter(this);
	painter.drawLine(x_from,y_from,x_to, y_to);
}

#include <QTableWidget>
#include <QTableWidgetItem>
#include <QPainter>
#include <QModelIndex>
#include <QAbstractItemView>


#include "draw.h"

Draw::Draw(QWidget *parent)	
{
	setRowCount(4);
	setColumnCount(4);
	this->setGeometry(0, 0, 500, 500);
}

void Draw::d_drawline()
{	
	int x_from = columnViewportPosition(1);
	int y_from  = rowViewportPosition(1);
	int x_to = columnViewportPosition(3);
	int y_to = rowViewportPosition(3);

	QPainter painter(this);
	painter.drawLine(x_from,y_from,x_to, y_to);
}

To copy to clipboard, switch view to plain text mode 

main.cpp:

#include <QApplication>
#include <QFont>
#include <QGridLayout>
#include <QHBoxLayout>
#include <QPushButton>
#include <QVBoxLayout>
 
#include "draw.h"
 
 
class MyWidget : public QWidget
{
public:
    MyWidget(QWidget *parent = 0);
};
 
MyWidget::MyWidget(QWidget *parent)
    : QWidget(parent)
{
 
    QPushButton *d_drawline = new QPushButton(tr("Draw"));
	Draw *draw = new Draw;
	connect(d_drawline, SIGNAL(clicked()),draw, SLOT(d_drawline()));
 
	QGridLayout *gridLayout = new QGridLayout;
	gridLayout->addWidget(d_drawline, 0, 0);
	gridLayout->addWidget(draw, 1, 0);
	setLayout(gridLayout);
 
}
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MyWidget widget;
    widget.setGeometry(200, 200, 500, 355);
    widget.show();
    return app.exec();
}

#include <QApplication>
#include <QFont>
#include <QGridLayout>
#include <QHBoxLayout>
#include <QPushButton>
#include <QVBoxLayout>

#include "draw.h"


class MyWidget : public QWidget
{
public:
    MyWidget(QWidget *parent = 0);
};

MyWidget::MyWidget(QWidget *parent)
    : QWidget(parent)
{
    
    QPushButton *d_drawline = new QPushButton(tr("Draw"));
	Draw *draw = new Draw;
	connect(d_drawline, SIGNAL(clicked()),draw, SLOT(d_drawline()));

	QGridLayout *gridLayout = new QGridLayout;
	gridLayout->addWidget(d_drawline, 0, 0);
	gridLayout->addWidget(draw, 1, 0);
	setLayout(gridLayout);

}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MyWidget widget;
    widget.setGeometry(200, 200, 500, 355);
    widget.show();
    return app.exec();
}

To copy to clipboard, switch view to plain text mode 

it builts successfully but nothing changes when i hit to draw button.

[wysota]

But why didn't you use visualRect()? I gave you practically a complete solution...

[kocakden]

Because i couldn't understand the QModelIndex class and couldn't use it (. But what is wrong with my code. While i'm debuging the code, i saw that it returns the coordinates correctly.

[wysota]

You can use visualItemRect() if you are using convenience classes. Your code is incorrect because it draws outside paint event.

Check out this example. Manipulate the spinboxes to see the effect.