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Mouse Event Zones On Canvas [message #640271]

Fri, 19 November 2010 20:27

Jonah Bron

Messages: 32
Registered: October 2010
Location: California

Member

Hello, world!

I'd like to create areas on my canvas in which if hovered over or clicked, something happens. Of course this can be done manually, but I just want to know if SWT provides tools to make this easier before I undertake the venture. There was nothing relevant to this as far as I could see in the canvas Javadoc, and I didn't find anything on Google.

Thanks

[Updated on: Thu, 25 November 2010 00:47]

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Re: Mouse Event Zones On Canvas [message #640570 is a reply to message #640271]

Mon, 22 November 2010 14:12

Lakshmi P Shanmugam

Messages: 279
Registered: July 2009
Location: India

Senior Member

Hi,

I didn't quite follow what kind of tool you are looking for?
You can do it using code -- add a listener to the Canvas to get the mouse events. The event's x and y fields are the coordinates of the mouse pointer and can help you determine if the mouse is within your area.

Lakshmi P Shanmugam

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Re: Mouse Event Zones On Canvas [message #640662 is a reply to message #640271]

Mon, 22 November 2010 17:57

Jonah Bron

Messages: 32
Registered: October 2010
Location: California

Member

Yeah. I mean something like adding a listener for, say, a Rectangle (object). It doesn't look like that's a built-in feature, though.

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Re: Mouse Event Zones On Canvas [message #640876 is a reply to message #640662]

Tue, 23 November 2010 12:24

Lakshmi P Shanmugam

Messages: 279
Registered: July 2009
Location: India

Senior Member

You cannot add listener to the Rectangle, but you can add listeners to the Canvas.
Here is a simple example:

final Canvas canvas = new Canvas(shell, SWT.NONE);
final Rectangle rect = new Rectangle(10, 10, 50, 50);
canvas.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
e.gc.drawRectangle(rect);
}
});
canvas.addMouseTrackListener(new MouseTrackListener() {
public void mouseHover(MouseEvent e) {
if (rect.contains(e.x, e.y)) {
System.out.println("hover inside rectangle");
} else {
System.out.println("hover outside rectangle");
}
}
public void mouseExit(MouseEvent e) {

}
public void mouseEnter(MouseEvent e) {

}
});

You could add the other Mouse listeners similarly.

Lakshmi P Shanmugam

[Updated on: Tue, 23 November 2010 12:25]

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