<AWT Dev> Paint a JComponent without clipping children

Herve Girod herve.girod at gmail.com
Wed May 4 15:14:40 PDT 2011


I'm new to this mailing list and I'm not *really* asking how to do it
because I know how it's possible to do it by using a hack (mainly getting
and setting the BUFFER and TILE parts of the "flags" field for the
JComponent by reflection, and "rewriting" the paintChildren method without
the clipping part). I'm using it in the
http://sourceforge.net/projects/j661/  project to be able to use custom
Swing containers which only offset the position or transform their children
graphic context, without clipping them (allowing to use negative positions
for the children widgets, for example).

I'm asking if there is a way to do this without playing with the private
"flags" field, because I need to be able to do the same thing in a
restricted JNLP environment. I know a "regular"' way to do this, but it
would be a little cumbersome (offsetting the positions of all children
widgets in the parent container, to be sure that the positions of the
children are never negative, for example). But it's not very good for
performance when something change in the parent container....

There are many projects which either play with this private field, or use
transforms, but in this later case they still apply a clipping. Is it
possible to play with the Graphics2D clippings for example before using the
JComponent paintChildren method - or would this approach work ?  Or would
the only way to do it without compromising Security be to have a way to get
/ set the TILE and BUFFER value of the "flags" field without reflection ?

Thanks by advance if you have ideas about this, and sorry if this prose is
not crystal clear ;)

Herve Girod
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