Zooming..

[chethana]

Hi all,

Presently i am working in qt4.2.2. As the example given in the Examples and demos i understood the working Image Viewer ...

But my problem is how to zoom the entire screen...

In that example they have used the QLabel... In that they have Loaded iQPixmap ... and then RESIZE and SIZE Functions QLabel they are using...
their they are getting the size of the image and multiplying with scale factor...
How to get the size of entire screen that i want to zoom???

[rajesh]

chethana,
which widget you are using?
check
width()
and height() function

[chethana]

I am sending the .bmp image red rectangle portion as i showed in the attachment that portion i want to zoom ... How to get the size ???

[chethana]

find out the attachment...

[rajesh]

that area is may be some widget or frame or dialog, right?
what is that? where you drawing these circle?
if you drawing these circle on some widget then you can write two slots:
void myWidget::zoomIn()
{
scale(1.25,1);
update();
}

void myWidget::zoomOut()
{
scale(0.8,1);
update();
}

[chethana]

HI ,

In a paint event i have written the codefor concentric circle... QMainWindow is my widget...

How to get control over client area... How to zoom the showed region...

[rajesh]

try this:
void MainWindow::zoomIn()
{
QPainter painter(this);
painter.scale(width() *1.25, height() *1.25);
update();
}
void MainWindow::zoomOut()
{
QPainter painter(this);
painter.scale(width() *0.8, height() *0.8);
update();
}

[rajesh]

OR
you can implement like this:

void MainWindow:aintEvent(QPaintEvent *event)
{
QPainter painter( this );
painter.drawPixmap( 0,0, m_buffer );
}
void MainWindow::updateWidget()
{
QPixmap tmp( 1200,900 );
tmp.fill(Qt::white);
m_buffer = tmp;
QPainter painter(&m_buffer);
...
painter.setBrush( QColor(120,120,120) );
painter.drawRect(rect);
. . .
}
void MainWindow::zoomIn()
{
QSize size( width() *1.25, height() *1.25);
m_buffer .scaled(size,Qt::KeepAspectRatio, Qt::SmoothTransformation)
update();
}

QPixmap m_buffer ; in .h file