Custom widget in QScrollArea

[ElRudi]

Hi,

i create a widget in a QScrollArea that should fill the entire widget with red color, but when i scroll to the right, i see that it's not filled completely. The frame is drawn correctly. Here is my code:

#include <QMainWindow>
#include <QPainter>
#include <QScrollArea>

class MyWidget : public QWidget
{
public:

	virtual void paintEvent(QPaintEvent* e)
	{
		QPainter painter(this);
		painter.fillRect(geometry(), Qt::red);
	}
};

class ScrollTest : public QMainWindow
{
	Q_OBJECT

public:
	ScrollTest(QWidget *parent = 0)	: QMainWindow(parent)
	{
		setGeometry(QRect(100,100,230,230));

		MyWidget* widget = new MyWidget;
		widget->setGeometry(QRect(0,0, 250, 250));
		widget->setStyleSheet("border: 3px solid blue;");

		QScrollArea* area = new QScrollArea(this);
		area->setGeometry(QRect(0,0, 200, 200));
		area->setWidget(widget);
	}
};

Here is a Screenshot: image

What's wrong?

Edit raven-worx: added code tags

[raven-worx]

did you try QScrollArea::setWidgetResizable(true)?

But the question is what you want to achieve, because actually a scrollarea's purpose is to show scrollbars if needed.

If setWidgetResizable() doesn't do what you want you need to subclass QScrollArea and reimplement it's resizeEvent() handler and resize the widget manually.

[ElRudi]

This is just a simple test dialog that shows my problem. The real widget is an image viewer/editor. I tried QLabel to draw the image, but this is very slow when you zoom in with large images. What i want to do is to zoom and scroll through the image.

If i call setWidgetResizable(true) i don't see the scrollbars and only a portion of the widget.

[ElRudi]

The solution is:

painter.fillRect(QRect(0,0, width(), height()), Qt::red);

geometry() delivers negative x/y values.