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

[Phil Race]

On 06/23/2016 05:04 AM, Alexandr Scherbatiy wrote:
>
> 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] 

You must mean the latter two as width and height of the bounding 
rectangle, not x2, y2.

bounds would be [7.5, 7.5, 15.0, 15.0] -
> for the scale 1.5 has bounds with rounded down upper-left  and rounded 
> up lower-right corners [7, 7, 8, 8] 

similarly you mean the width/height would be rounded up to 8 - not the 
corner location.

anyway .. +1 from me but this is one Jim should look at too.

-phil.


> 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.
>
>