clipping transformed objects causes unexpected results
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| Inkscape |
Confirmed
|
Undecided
|
Unassigned | ||
Bug Description
When clipping two objects where one has at least a transform matrix, the result is not as expected.
Note that (when trying to reproduce it again and again) this only affects if "scale stroke" and "scale radii" is disabled!
Thanks to su-v we've broken down the issue to this description on irc.
Attached example shows an ellipse with transformation that gets clipped with some clip path (rectangle with radius)
The border radius after clipping is different than it was before. This seems to be because of the current transform matrix on the ellipse.
While the order of execution (first filter, then transform) may be perfectly matching SVG specs, this leads to unpredictable results from a users perspective. If a user applies two objects (no matter if transformed or not) to clip, the resulting clipping should be exactly what's been visible to the user before. No matter which scale settings are enabled (this makes absolutely no sense).
Might be related to:
https:/
| Miro Dietiker (miro-dietiker) wrote | #1 |
| tags: | added: clipping transformations |
| Changed in inkscape: | |
| status: | New → Confirmed |
| su_v (suv-lp) wrote | #2 |
| su_v (suv-lp) wrote | #3 |
reproduced with Inkscape 0.47 and 0.47+devel r9433 on OS X 10.5.8
The main problem IMHO is that it is not transparent for the user if an object has an explicit transformation attribute (like any transformed ellipse, star/polygon or spiral) or optimized transforms, and it's even harder to anticipated if the shape has been converted to path but not transformed after that (because the path still has the preserved transform attribute after the conversion).
Resorting to the XML Editor to check the attributes of an object to be clipped is just a workaround and not user-friendly. A "Filter properties" dialog as proposed in bug #168157 allowing transformations to be inspected and maybe modified at every level of the stack could provide a better solution.