在Mac OS X中获取AWT框架的可绘制区域？

Question

I have subclassed java.awt.Frame and have overridden the paint() method as I wish to draw the entire contents of the window manually.

However, on the graphics object, (0,0) corresponds to the upper left hand corner of the window inside the title bar decoration, not the first drawable pixel.

Can I determine the co-ordinate of the first drawable pixel (ie, the height of the decoration) in a cross-platform manner, avoiding using a Mac OS X-specific fudge factor ? Will I be forced to nest a Panel component in order to find the actual drawable area of the window?

Here, my code fails to centre the blue square inside the paintable area of the window:

@Override
public void paint (Graphics g) {
    g.setColor(Color.BLUE);
    g.setPaintMode();
    g.fillRect(30, 30, getWidth()-60, getHeight()-60);
}

Answer 1

You can find the frame insets by calling the getInsets method (defined in Container). Frame insets are discussed at the top of the Frame API docs.

Answer 2

So you want to paint the whole area and don't want a title bar at all?

Assuming that you use JDk 1.4 (at least) then you can declare the frame to be "undecorated" (java.awt.Frame#setUndecorated(boolean)). This way no title bar is created and therefore the frames-paintable area is the same as the frames-consumed area.