Bug 81137 – getIntersectionList returns false positives when the coordinate system has been rotated

• Status: UNCONFIRMED
• Component: SVG

[Oscar Kozlowski]

Created attachment 131886 [details]
Repro case

getIntersectionList appears to use axis-aligned bounding boxes for intersection testing, resulting in false positives being returned when the coordinate system has been rotated.

Steps to reproduce: 
1. Open attached mininmal repro (svg_getIntersectionList_rotation_bug.svg). This repro attaches a mouse move handler that retrieves the intersected SVG elements directly under the pointer. If the rectangle is intersected, it is highlighted red, otherwise it is green.
2. Move mouse over the green rectangle. Rectangle is highlighted red as expected.
3. Move mouse out of rectangle but within the axis aligned bounding box (e.g. screen coordinate (0, 0)). Rectangle remains red, but expected to revert back to green.
4. Move mouse further out of the axis aligned bounding box. Rectangle turns green as expected.

Correct behaviour under IE9 and Opera.

[Daniel Trebbien]

The issue is that WebKit is considering the bounding box.

See the bug report for Chrome: http://crbug.com/370012

[Pete Thompson]

Is there any plan to fix this? I'm making use of the getIntersectionList method and am getting false positives due to rotated elements.