– I'm on Windows 10, German edition, and on Inkscape Inkscape 1.2 (dc2aedaf03, 2022-05-15).

– I've got a document containing a path atop a rectangle, both having an equal stroke width of 5 px.

– I've unset the preferences option to scale stroke width.

– I've unset the icon in the top right corner with the tooltip, “When scaling objects, scale the stroke width by the same proportion”.

– I select both objects and transform the width, not the height.

See 1st screenshot, highlighting in purple just what I did.

I was hoping that the stroke width should remain at 5 px after the transformation, just as I specified. But instead, the transformation does affect the stroke width; it is now far thicker than 5 px at the top and bottom and far thinner than 5 px at the sides. This pertains to the pure path (top) as well as to the rectangle (bottom).

So how do I stop this annoying effect? Extensive googling hasn't turned up an answer, besides turning off the two options that I did turn off.

Seems you put it as a group;  ungroup and transform again please.

("ungrounded"? Damn autocorrection) 🙄

You can also do this without ungrouping. [double-click] or [ctrl+return] to enter the group. Select all [ctrl+a]. Now you can stretch your shapes, preserving the stroke thickness. [ctrl+backspace] to leave the group.

A simple ungroup and regroup usually works for me.

In the original experiment above, I selected the two objects together, I didn't group them. But, fair enough:

I'm repeating the experiment using just 1 object, a path with 3 nodes. Shrinking the path horizontally but not vertically still repeats the effect that the stroke width is scaled, and scaled unevenly.

@Paddy_CAD

It seems that your second constellation shows the effect I was talking about: The stroke thickness in the horizontal portions of the stroke is bigger than the thickness in the vertical portions. The third constellation is different: Now the strokes have uniform thickness. What did you do to get from #2 to #3?

..

Can you show us a screenshot of the 2 parts you selected in the first screenshot in the Object->Layers and Objects panel?

@Polygon

Here you go. I'm attaching:

• The .svg
• Picture: Selecting (with the mouse, not grouping) and shrinking both objects
• Picture: Selecting and shrinking just the path (upper object)
• Picture: Selecting and shrinking just the rectangle (lower object)

In all cases, the stroke at the top & bottom becomes thicker, the strokes at the sides become thinner.

In my comment #3 above, the centre shapes are a group of two objects. Scaling svg groups stretches stokes and fills alike. The shapes on the right are not grouped so stroke widths were preserved. This is the expected behaviour.

I opened your svg attachment and used the Select tool [s] to stretch the shapes. Stroke thickness was preserved. I see thinning and thickening of strokes while dragging the selection handle, but it reverts to the original stroke width when I release the mouse button.

The XML Editor shows transforms applied to your shapes so I went to Inkscape Preferences then [Behaviour > Transforms > Scale stroke width]. This changed from no thickening to uniform thickening, but not the uneven thickening in your screenshots.

I'm at a loss. I can't explain your experience. What happens if you use the node tool [n] and [ctrl+drag] to scale the shapes?

What can I do to show you more about my setup?

Here's the preferences.xml file in %APPDATA%/Roaming/Inkscape (attached).

Perhaps you can download this svg image. Scale the shapes and tell us what happens.

Pretty sure you scaled the Layer and not the object then:

This Transform Matrix will stay alive and is valid for any applied objects unless you´ll correct it or delete that layer and generate a new one:

Well spotted Polygon!

@Polygon

So, here's an all new document (attached, uneven-stroke0.svg).

• The first pic (attached, 5a) shows all of the XML of the document and the attributes of the node with id layer1: Layer 1 does not have any matrix transformation.
• The second pic (attached, 5b) shows the attributes for the node with id rect1090: The rectangle does not have anx matrix transformation
• As before, I now shrink the rectangle horizontally but not vertically – by grabbing the middle right handle “⇔” and moving it to the left.
• Now, I get the situation in the third pic (attached, 5c): Distorted stroke. Now the rectangle does have a transformation, but that's kind of the point of the horizontal but not vertical shrinking.
• The fourth pic (attached, 5d) shows that the layer, however, still does not have any transformation.

I´m not able to recreate this following your steps. Are you really sure you´re not scaling the Layer instead of the rectangle by accident? Once you scaled the Layer all objects will have a transform matrix unless you delete it in XML editor.

I don't know what to say.

I'm now including a film (window capture) that shows exactly what I'm doing, in file 2023-10-28_18-30-50.mp4. I've saved the document immediately before that (uneven-stroke0.svg) and immediately afterwards (uneven-stroke1.svg)

I've opened both files in Notepad++ and had it compare them to each other, and I can't see any transformation to the group <g … id="layer1"> that might have been added by my handling. Differences would be highlighted in the screenshot uneven_stroke6.png. In the "before" document uneven-stroke0.svg, the group does not have a transformation, as also shown in the screenshot.

The result is in the screenshot uneven-stroke6.png, attached, showing the stroke distortion. Even when I close Inkscape completely and re-open it with uneven-stroke1.svg, it shows the distortion (shown in screenshot uneven-stroke6.png).

Note that I'm transforming the rectangle, not the triangle, which both are children of the layer. If I was transforming the layer, wouldn't both the triangle and the rectangle be affected?

I still don´t get how you introduce the transform matrix just by scaling the object horizontally. This is how your file works here. Notice that I´m deleting the tag from the XML and it won´t get introduced again:

Does Inkscape always works that way or just started after an update? if the latter please consider: Inkscape Preference->System hit "Reset Preferences" and restart Inkscape. Fingers crossed.

Open Inkscape Preferences then [Behaviour > Transforms > Store Transformation > Optimised]. In your case [Store Transformation > Preserved] applies a transform when you scale an object in your drawing, instead of recalculating the node positions.

I should have remembered this sooner, but I think we finally got there.

Hurray. Never touched this in Preferences so I totally forgot about this.

@Paddy_CAD

Can confirm that setting Edit > Preferences > Behavior > Transforms > Store Transformation  to  “Optimized” solved my problem.

Thanks a lot!