[OpenJDK 2D-Dev] <AWT Dev> [9] Review Request: JDK-8029455 JLightweightFrame: support scaled painting

Anthony Petrov anthony.petrov at oracle.com
Tue Feb 4 18:55:23 UTC 2014

Hi Anton,

I skimmed through the code that I'm familiar with, and the changes look 
good to me. Someone from Swing and 2D should review their parts, too.

best regards,

On 2/3/2014 6:36 PM, Anton V. Tarasov wrote:
> Hi Jim,
> Please look at the updated version:
> http://cr.openjdk.java.net/~ant/JDK-8029455/webrev.4
> On 01.02.2014 5:35, Jim Graham wrote:
>> Hi Anton,
>> On 1/31/14 6:37 AM, Anton V. Tarasov wrote:
>>> My understanding is that, unless the fix is absolutely irrelevant (whic
>>> I hope it isn't), we should integrate it into 9/8u20 to support
>>> SwingNode in its current implementation on Retina displays.
>>> What do you think?
>> I agree with this sentiment.  My suggestion for reducing its footprint
>> aside (which it looks like you are investigating), the main thing I
>> will be looking for is whether or not we return an object to a
>> developer (i.e. it isn't just managed internally to our own code)
>> where they can do "instanceof BufferedImage" and then see something
>> odd coming from its width/height.
>> It looks like if we simply use getLayoutWH() internally then they
>> would never ever see anything odd from getWidthHeight() anyway. The
>> only additional "gotcha" would be if they grab the image and render it
>> directly and it comes out an unexpected size to them (because, for
>> instance, they didn't check the layout dims like we do internally).
>> That's a pretty minor issue, though, and I think we could live with it.
> I've refactored the fix with this concern in mind. Here is what I've done:
> - eliminated the new OffscreenHiDPIImage class (as you suggested) and
> put all of its "scale" logic into the OffscreenImage.
> - made the scaled OffscreenImage return the physical size (like an
> ordinary BufferredImage does) by default .
> - renamed the "set/isHiDPIEnabled" method to "set/isReturnLayoutSize".
> - made the setReturnLayoutSize(true) be called internally (where we
> don't leak the OffscreenImage).
> In SG2D, the drawHiDPIImage, for instance, makes a call to
> op.filter(img, null); where the img is expected to return its layout
> size. That's why I still prefer to use the setReturnLayoutSize
> "switcher", in order not to go deep into the 2D rendering code, casting
> here and there to OffscreenImage and calling getLayoutWidth/Height.
>> For 9.0 perhaps we could add the LayoutWH() as new API on
>> BufferedImage and then most of this would be public?  I'd have to mull
>> over if that makes sense and I'm not entirely sure of the naming yet...
> That's a good idea, however we need a 8u working solution as well... As
> to the naming, I'm ready for any suggestions.
> Thanks,
> Anton.
>>             ...jim

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