David Daney wrote: > Roman Kennke wrote: > > Hi Gary, > > > > > > > The setComposite method of anything that extends java.awt. > > > > > Graphics2D is supposed to do a permisson check if "...this > > > > > Graphics2D context is drawing to a Component on the display > > > > > screen and the Composite is a custom object rather than an > > > > > instance of the AlphaComposite class." The latter is easy > > > > > to check, but how do I tell whether the context is drawing > > > > > to a Component on the display screen? > > > > > > > > Only one subclass of CairoGraphics2D draws on the screen, I > > > > think this is ComponentGraphics. > > > > > > Ok. Do you know about its subclass, VolatileImageGraphics? > > > > VolatileImage doesn't draw on the screen. It draws on a backbuffer > > (an XImage really). I don't know if that counts as drawing on > > screen though. Because the backbuffer should be synced with the > > screen sooner or later. But maybe you try against the JDK > > (Component.createVolatileImage() gives you a VolatileImage > > instance). > > The check is for "readDisplayPixels", so something that is not > visible would seem to be exempt.
Yeah. The problem is that AWT is complex enough that it's not obvious to me which classes of which peers might allow code to get at the pixels and which can not. Any help in that area is much appreciated. Cheers, Gary
