Swing: creating a JScrollPane that displays its component centered?

Question

If you create a JScrollPane that has a viewport larger than the JScrollPane\'s component, it displays that component in the upper left.

Is there any way to change this b

Answer 1

Accepting your both comments, but

yes... although I'd really like to arbitrarily position it

there are

• extract or to create own JViewport

important methods to avoiding flickering or jumping on the JViewport

JViewport.setScrollMode(JViewport.BLIT_SCROLL_MODE); JViewport.setScrollMode(JViewport.BACKINGSTORE_SCROLL_MODE); JViewport.setScrollMode(JViewport.SIMPLE_SCROLL_MODE);

• use GlassPane (is very simple to set for possition to the desired Point or/and Dimmension)

and

I don't want to paint to the JViewport, at least not directly -- My real code is a component subclassed from JPanel, as in my example, but it also has other GUI elements in it.

• you can use JXLayer (Java6) or parts of methods from JXLayer implemented to the JLayer (Java7) directly

• could be too hard, but in all cases you can overlay whatever with JLabel

Notice

all my suggestion to consume MouseEvent by default, J(X)Layer and JLabel with KeyEvents too, but there no issue with redispatch events from ---> to another JComponent

EDIT

wait: no, I don't want to paint the spiral (what you called "snake") in the center of the JScrollPane; I want to paint my component and have my component be displayed in the center of the JScrollPane.

• your JPanel could be wider than JViewport by default

a) JPanel returns Dimension

b) JViewport return Dimension

• then without any issue, flickering or freeze

a) you can centering Dimmension from JPanel (Point) to the center of JViewport (Point)

b) if is there JComponent you can move the JViewport to any getBounds() tha returned JComponent or Point from JPanel inside JScrollPane