<Swing Dev> <SwingDev> [9] Review request: 8033233 [JLightweightFrame] support default JViewport BLIT_SCROLL_MODE

[Petr Pchelko]

Hello, Anton.

Great, you are removing the dirty JViewPort hack) 

I have one question: is JViewport a single place where we use the "blit" rendering?
Also, could you please update the copyright years.
Also, may be we could replace the RepaintListener instantiation in JLWF with a lambda? What do you think?

With best regards. Petr.

On 30.01.2014, at 17:49, "Anton V. Tarasov" <anton.tarasov at oracle.com> wrote:

> Hi all,
> 
> Please review the fix.
> 
> jira: https://bugs.openjdk.java.net/browse/JDK-8033233
> webrev: http://cr.openjdk.java.net/~ant/JDK-8033233/webrev.0
> 
> Here I'm duplicating JIRA:
> 
> The point of the fix is that it introduces a RepaintListener which can be added to a RepaintManager in order to get back notifications of repaints performed as BLITs. JLightweightFrame registers such a listener to its RM instance. JViewport is the source of those notifications. Now it works in default BLIT_SCROLL_MODE.
> 
> Shortly, the mechanism of repainting of a JLF is the following. Once a JLF's child component is requesting repaint, an appropriate repaint runnable is scheduled by the RepaintManager (RM). The runnable is then gets dispatched by the RM which calls the paint() method of the root component, that is the JLF. JLF overrides this method in the way that after all the painting is done (super.paint) it initiates a pixel bits transfer to the host application (e.g. SwingNode). In case of JViewport, when it works in the default BLIT scroll mode, scrolling of the JViewport doesn't lead to a repaint runnable being dispatched. Instead, JViewport immediately repaints its content (via blitting + repainting a dirty area) and then tells the RM there's nothing to repaint (so the runnable scheduled is just skipped). As the result, the JLF doesn't get any notification of the update.
> 
> As a workaround to this problem, JViewport had been forcibly switched to the BACKINGSTORE scroll mode, in which case it passes the whole repainting cycle.
> 
> Regards,
> Anton.