Extension Visualize path gives weird results

[ivan louette]

This is the first time I use the Center of Mass feature in the Vizualize path extension.

I use Inkscape Trunk on Kubuntu 14.04

I have thought that Extension/Vizualize Path/Measure Path/Center of Mass could help me to locate the hanging hole in flat shapes designed for an hanging mobile. But in some cases it gives weird results. It seems this is not related to the fact that the shape is a composite path or not.

I attach an example of what occurs in some cases.

Thanks for any help !

ivan

[su_v (suv-lp)]

Attaching proposal to fix insertion of 'center of mass' symbol in transformed layers - please review.

[su_v (suv-lp)]

Reproduced with Inkscape 0.91 r13725 and lp:inkscape/0.92.x r15309 on OS X 10.7.5.

[su_v (suv-lp)]

Needs fixes for other use cases of center of mass too (to position text labels for length and area) - updated patch later.

[su_v (suv-lp)]

Updated proposal, includes fixes for text labels inserted at path start or center of mass, if selected path is inside transformed (translated) group or layer.

[ivan louette (ivan-louette)]

My question was also why the center of mass location is so far outside the object and far from the potential center of gravity of the shape (assuming it has an homogenous weight everywhere on its surface).

My goal is to insert an hanging hole somewhere on its balance line.

[su_v (suv-lp)]

ivan - the answer to the question «why the center of mass location is so far outside the object» is that the extension currently does not correctly take the translate() transformation of the parent layer group into account when drawing the path to symbolize the center of mass:

  <g
     transform="translate(1575,2067.6377)"
     id="layer1"
     inkscape:groupmode="layer"
     inkscape:label="Layer 1">

[su_v (suv-lp)]

@ivan - a quick workaround in any affected file is to
1) add a new layer
2) move the path to the new layer
3) apply the extension

[ivan louette (ivan-louette)]

Ok the workaround works very well ! Thanks a lot and sorry for my misunderstanding.

I will try the result on paper shapes soon.

[jazzynico (jazzynico)]

Reproduced on Windows XP (32-bit), lp:inkscape/0.92.x rev. 15309.

[jazzynico (jazzynico)]

Patch tested quickly with the SVG file attached comment #1. Looks perfect, but needs some more tests.

[su_v (suv-lp)]

Minor correction of v2.

[su_v (suv-lp)]

Deleting the attached diffs - I am revoking my pending patches provided in this bug tracker for issues with python-based extensions distributed with Inkscape.

[Jonathan Hofinger (jhofinger)]

Closing; this was fixed in https://gitlab.com/inkscape/extensions/-/merge_requests/314 for Inkscape 1.2.

Closed by https://gitlab.com/jhofinger