<AWT Dev> [11] Review Request: 8196030 and 8190326

Sergey Bylokhov Sergey.Bylokhov at oracle.com
Fri May 18 19:38:02 UTC 2018

Please review the fix for jdk11.

     8196030: AWT Robot mouseMove fails on Windows 10 1709 with HiDPI
     8190326: Robot.mouseMove uses scaling factor of main display on 
unscaled second display

Webrev: http://cr.openjdk.java.net/~serb/8196030/webrev.04

  This change will fix two issues:
  - 8196030: In the Windows 10 relative mouse moving is broken. Solution 
is to change the code to use the absolute mouse location. Actually the 
fix reverts the changes which were done in JDK-4288230 [1](It is 
interesting that previously the absolute mouse position was broken). 
Take a look to the function which is used to calculate the mouse 
position, this is the only way I found to align coordinates which passed 
to windows(::SendInput() and coordinate which returned by 

  - 8190326: the logic how we convert coordinates from the user space to 
device space is changed. Previously we use the transformation of the 
main screen, now we will find the appropriate screen(where coordinates 
are located) and then use transformation of this screen.

I have tested the fix on win7/10 using scales:100%,125%,%150,%175,%200 
in multi-monitor configuration. But the new test is quite strict and may 
fail if there are some rounding error in some variations of screen 
resolution+scale+screen locations. So I expect some reports for this test.

  - The logic in the new method in SwingUtilities2 is similar to 
Robot.createCompatibleImage(), but the new method uses 
Region.clipRound() instead of floor/ceil. The reason is that we use same 
logic in native. I think that Robot.createCompatibleImage() should use 
clipRound() as well. Will check this later in separate bug.

  - Similar but not the same bug exists in Robot.getPixelColor() which 
uses the scale of the main screen, and uses simple cast to (int), but it 
affects all platforms. Will check this later in separate bug.

[1] https://bugs.openjdk.java.net/browse/JDK-4288230

Best regards, Sergey.

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