画布的JFrame像素精度

Question

Hey so I'm implementing a Canvas in a JFrame object, however there's a slight annoyance:

If I specify the frame to be a certain dimension, then the title bar is included in the vertical size. Similarly for the left edge of the window being included with the specified size. I used absolute positioning to determine the pixel count for the title bar and just made my JFrame that quantity of pixels larger, however I somehow doubt this is platform independent. Is there a proper way to get/set the quantity of pixels that can appear inside the actually usable contents of a JFrame?

Answer 1

Usually you place your "canvas" (which should not be a java.awt.Canvas , but preferably a javax.swing.JPanel ) into the content pane of the frame. When you assign a preferred size to this component, and afterwards call pack() on the frame, then the frame will have the right size to obey the preferred size of the component:

canvas = new MyClassExtendingJPanel();
canvas.setPreferredSize(new Dimension(123,456));
frame.getContentPane().add(canvas);
...
// At the end:
frame.pack(); 
frame.setVisible(true);