Mozilla wants us to reexamine the pointer-events model, including potentially new, more intuitive values. This would also be applicable to masks, clips, filters, and other effects. The model should take into account CSS and HTML, as well.
Here were some of the errata we decided to forego in order to keep options open for a revision in SVG 2.0:
Capturing pointer-events with a zero opacity mask Category: 3 In reference to: http://www.w3.org/TR/2003/REC-SVG11-20030114/interact.html#PointerEventsProperty Description It's unclear whether if an element has a mask, pointer-events are still captured even in areas where the mask goes to zero opacity. Don't want nearly transparent and fully transparent to behave differently. Resolution If an element has a mask, pointer-events are still captured even in areas where the mask goes to zero opacity. Change In http://www.w3.org/TR/2003/REC-SVG11-20030114/interact.html#PointerEventsProperty, change: to: 16.6.1 Clipping paths, masking, and pointer events The effects of masking and clipping differ with respect to pointer-events. A clip path is a geometric boundary, and a given point is clearly either inside or outside that boundary; thus, pointer events must be captured normally over the visible areas of a clipped element, and may be captured normally over the clipped areas depending upon the different values of the pointer-events property, as described in the definition of clipping paths. By contrast, a mask (like a filter) is not a binary transition, but a pixel operation, and different behavior for fully transparent and 'almost but not fully transparent' would be confusing; as a consequence, for elements with a mask applied, pointer-events must still be captured even in areas where the mask goes to zero opacity. If an author wishes to achieve an effect where the transparent parts of a mask allow pointer-events to pass to an element below, a combination of masking and clipping may be used.
Unclear how clip-path affects bounding boxes Category: 3 Test case: clip-pointer-bbox.svg Description It is unclear whether the bounding-box of an object should take into account a clip-path on that object. Resolution The clip-path should not affect the bounding-box, but the getRenderedBBox would be affected by stroke, markers, filters, and clip-path. Note: this erratum is resolved by another erratum, 'clippath-pointer-events'
Clarify clipPath and Pointer-Events Category: 3 Reported by: Doug Schepers Comment: Description It is unclear where pointer events should be triggered on elements with a clipping path applied. Resolution An explanation of the different values for 'pointer-events' and how they are affected by a clipping path will be added. Change In http://www.w3.org/TR/2003/REC-SVG11-20030114/masking.html#EstablishingANewClippingPath, change: to: 14.3.6 Clipping paths, geometry, and pointer events A clipping path is conceptually equivalent to a custom viewport for the referencing element. Thus, it affects the rendering of an element, but not the element's inherent geometry. The bounding box of a clipped element (that is, an element which references a 'clipPath' element via a 'clip-path' property, or a child of the referencing element) must remain the same as if it were not clipped. With regards to pointer-events, while the visible parts of a clipped element receive pointer events normally, parts of a clipped element which are outside the extent of the clipping path must be treated as if they have a 'visibility' property value of 'hidden'. Therefore, an element which has 'pointer-events' property values which depend upon the visibility of the element (i.e. 'visiblePainted', 'visibleFill', 'visibleStroke', 'visible') will not receive pointer events outside of the clipping region, regardless of the setting of the 'visibility' property. Within the clipping region the 'visibility' property acts normally on event sensitivity. For example, a circle with a radius of 10 which is clipped to a circle with a radius of 5 will not receive 'click' events outside the smaller radius if it has the default 'pointer-events' property value of 'visiblePainted', but will if has the property value of 'all' or 'fill', for example. Note that for a child element of an element that references a clip-path, the relevant 'pointer-events' value is that of the target element (i.e., the child element), not the parent element. In other words, if a 'g' element has both a 'clip-path' property and the 'pointer-events' property value of 'visible', but a 'circle' child element has a 'pointer-events' property value of 'all', then the circle would be sensitive to pointer events even if it were clipped. Note that this property-dependent event clipping behavior applies only to elements clipped by the 'clip-path' property. For elements clipped by elements that establish a new viewport, such as nested 'svg' elements, events are always clipped for the clipped portions of a target element.