Hello Everyone


Good day to you.


Request your time in reviewing the fix for-

      Bug : JDK-8165212

      Title : VolatileImage should not be compatible with GraphicsConfiguration 
which transform is changed


Description on the bug-

       . As per the bug, Volatile Image's graphics configuration is not updated 
when the host machine display's DPI is changed at runtime (while still running 
the java app). In addition, the method contentsLost() does not return true when 
display's DPI is modified.

       . It is important to note that, the issue is not reproducible with 
D3D/OpenGL backend. It is reproducible with non-accelerated Volatile Image.


Root Cause

       . A callback method- displayChanged() in VolatileSurfaceManager.java is 
invoked when display's settings (DPI) is modified.

       . The callback method, currently, updates the graphics configuration 
only for Accelerated volatile image. Graphics configuration is not updated for 
non-accelerated system memory based VolatileImage.

       . Until recently, there wasn't any need for updating graphics 
configuration for non-accelerated volatileImage. However, Win 8.1 and above 
provide feature to dynamically update the DPI setting (without requiring for 
log-off/ log-in), which causes the current bug.


Bug Fix

      . First, the callback method is modified to update graphics configuration 
for non-accelerated volatile image also.

      . An update to graphics configuration might require re-creation of the 
surface. Especially, when the scale factor is increased. Hence the system 
memory based backupSurface is re-created here.

      . The above change is followed by change to Validate() API, so that the 
backup surface re-creation in displayChanged() method, correctly returns 
IMAGE_RESTORED from validate() API. This way, the code flow for non-accelerated 
Volatile Images behaves just the same way as accelerated volatile images.

       . Approximately 81 Jtreg test cases (that contained VolatileImage) were 
run on win7, linux, and osx. No new regressions have been found after the 

       . In addition, a manual test case has been provided to ensure the proper 
functioning of the fix


Kindly review the changes and provide your suggestions

Review link: http://cr.openjdk.java.net/~pnarayanan/8165212/webrev.00/


Thank you for your time in review

Have a good day


Prahalad N.

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