Hi,
[EMAIL PROTECTED] wrote:
In simplified terms, I have a situation where I am drawing a large filled Rectangle and
then drawing other smaller filled rectangles in front of or on top of the large one. The
rectangles at the front do not completely cover the large rectangle at the back so there
is a region of the back rectangle around the smaller rectangles that "shows
through" so to speak.
The question is, is it possible (perhaps with some form of "negative" clipping)
to repaint the background colour of the large rectangle without having to repaint the
smaller rectangles as well? So, just the area that shows through from the large
rectangle is repainted. At the moment, I have to repaint the large rectangle and then
all the smaller ones as well which is clearly too expensive.
First of all, did you determine (by profiling and such) that it
is expensive or is this your gut feeling? It is important
to work with correct data, and sometimes our
assumptions about performance implications may be
incorrect (I get this stuff wrong all the time).
Anyway, assuming that it is super-expensive to repaint
the whole thing, you can construct a clip shape
(which would be your bg rectangle minus your small
rectangles) and set it on the graphics context.
That way the area of the bg rectangle which isn't
covered by smaller rectangles only will be repainted.
Shape clip may be an expensive operation, though
(depending on the pipeline), so I would still
suggest to profile (or just time) both
approaches.
Thanks,
Dmitri
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA2D-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
