[OpenJDK 2D-Dev] [9] Review request for 8160124 SunGraphics2D.hitClip() can give wrong result for floating point scale

[Alexandr Scherbatiy]

Hello,

Could you review the fix:
   bug: https://bugs.openjdk.java.net/browse/JDK-8160124
   webrev: http://cr.openjdk.java.net/~alexsch/8160124/webrev.00

   Let's set the clip [x=5, y=5, width=5, height=5] to a graphics and 
call the hitClip() with the passed rectangle [x=0, y=0, width=5, height=5].

   The result is false for the graphics with scale 1 and true if the 
scale is floating point 1.5.

   This is because the transformed clip which has floating point bounds 
[7.5, 7.5, 7.5, 7.5] for the scale 1.5 has bounds with rounded down 
upper-left  and rounded up lower-right corners [7, 7, 8, 8] which now 
intersects with the transformed rectangle [0, 0, 7.5, 7.5].

   The proposed fix adds additional check for the user clip and the user 
rectangle intersection if the intersection with the region clip passes.

  Thanks,
  Alexandr.