get in the center of the composite? eclipse - eclipse

Question

My purpose is to draw in the CENTER of the composite. Actually, I have an rcp view and I'm drawing some shapes inside it. this is the code that I use :
display = parent.getDisplay();
white= display.getSystemColor(SWT.COLOR_WHITE);
parent.setLayout(new FillLayout(SWT.VERTICAL));
// Create the ScrolledComposite to scroll horizontally and vertically
final ScrolledComposite sc =new ScrolledComposite(parent, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
sc.setExpandHorizontal(true);
sc.setExpandVertical(true);
sc.setMinHeight(100);
sc.setMinWidth(100);
sc.setSize(100,100);
Composite child = new Composite(sc,SWT.NONE);
child.setLayout(new FillLayout());
child.layout(true);
parent.addListener (SWT.Resize, new Listener () {
public void handleEvent (Event e) {
x = child.getBounds().width/2;
y = child.getBounds().height/2;
child.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent event) {
dessin(gc); // to raw the circle
}
});
sc.getDisplay().update();
}
});
I defined the view with a ratio (so when the view is empty I get the wanted size)...I don't know the exact size of the view since it can be resized by the user at anymoment, or when an editor is opened... So, my problem is how to draw just in the center of the view and keep the drawings in the center even if the view is resized...
PS: Using (Point.x and point.y), I get (0,0) when the view appears first, then I get other values...
Pleaaaaaaaaaaaaaase help

Answer 1

You can use getOrigin() method on ScrolledComposite, which will return Point instance with the point in the content that currently appears in the top left corner of the scrolled composite. See docs getOrigin method on ScrolledComposite.
With that information and size of the component which you'll get from getBounds() method you can easily calculate the 'real' center.