Java (Swing): finding a component's *screen* size when the window is resized

I need to find a component's exact screen size in pixels when the main JFrame is resized.

I've tried several things and couldn't find an easy way to do it: it probably have missed something obvious.

BBBBB JFRAME BORDER BBB
BZZZZZZZZZZZZZZZZZZZZZB
BAAAAAAAAAAAAAA开发者_如何学CAAAAAAAB
BCC1................DDB
BCCC................DDB
BCCC................DDB
BCCC................DDB
BCCC................2DB
BEEEEEEEEEEEEEEEEEEEEEB
BBBBBBBBBBBBBBBBBBBBBBB

Resized, it could become this if, say, the user made the main JFrame shorter (vertically) and wider (horizontally):

 BBBBBB JFRAME BORDER BBBBBB
 BZZZZZZZZZZZZZZZZZZZZZZZZZB
 BAAAAAAAAAAAAAAAAAAAAAAAAAB
 BCC1....................DDB
 BCCC....................2DB
 BEEEEEEEEEEEEEEEEEEEEEEEEEB
 BBBBBBBBBBBBBBBBBBBBBBBBBBB

What I want is to find the exact size in pixels, on screen, of the rectangle area indicated by dots.

I'm adding a ComponentListener to get the resizing events, which works fine.

The issue I'm having is that calling getWidth()/getHeight() on a Component does apparently not return the component's screen size but the component's actual size (and you can have, for example, a JPanel wider than the component it is into).

Any hint most welcome.

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You're looking for JComponent.getVisibleRect().

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getWidth() and getHeight() returns the width and height of the component. I've never heard of any difference between "actual" width/height and "screen" width/height.

Some layout managers however, does not fill the panel with a component it contains, and some space between the component and the panels edge may not be occupied by the component. In that case I usually setBackground(Color.BLUE) on the underlying panel to see what's going on.

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This is a very rubbish way but you can use a wrapper Panel, where you put your main panel into. Than you can call getWidth() and getHeight() from the wrapper panel.