randomized star/polygon changes shape when scaled with locked ratio (rev >= 12554)

[su_v]

Follow-up report to
Bug #1348375 “trunk: randomized star/polygon changes shape when moved (rev >= 12554)”

A star/polygon with 'Randomized' parameter > 0 changes shape when scaled with locked ratio (on-canvas with 'Ctrl' pressed or using the options on the select tool controls bar).

Steps to reproduce:
1) launch 0.91 or current trunk (default new prefs, default new doc)
2) draw a star
3) change parameter 'Randomized:' to e.g. 0.2
4) switch back to select tool
5) scale the star uniformly

Expected result:
The star shape is scaled up or down with same width/height ratio, but stays unchanged otherwise.

Actual result:
The star shape is scaled to fit the new size of the selection bounding box, and the shape gets regenerated (i.e. may change completely).

Reported for Inkscape 0.91 on the user mailing list, reproduced with 0.91 r13725 and 0.91+devel r14285 on OS X 10.7.5

Based on tests with archived builds:
- not reproduced with Inkscape 0.48.5 r10040
- not reproduced with 0.48+devel rev <= 12552
- reproduced with 0.48+devel rev >= 12555
this perceived regression was likely introduced with the merge of the GSoC unit-improvement branch in r12554, which changed how transforms for parametrized shapes are optimized (if possibly, transforms get optimized and reflected in the shape parameters instead of stored in a preserved 'transform' attribute):
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/changes/12555>

Notes:
- affects stroked and unstroked paths with default stroke scaling (scale stroke width)
- does not affect stroked stars if 'scale stroke width' is toggled off
- non-uniform scaling, rotating or skewing the randomized star prevents the regression from happening (adds a 'matrix()' transformation)
- does not happen with 'preserved' instead of 'optimized transforms (as expected)

[Jonathan Hofinger (jhofinger)]

Hi - thanks for reporting this bug, I've manually migrated it to Inkscape's new bug tracker on GitLab, and closed it here.

Please feel free to file new bugs about the issues you're seeing at http://inkscape.org/report.

Moved to: https://gitlab.com/inkscape/inbox/issues/2017
Closed by: https://gitlab.com/jhofinger