Created attachment 156706 [details] mirror horizontal The attached documents contain macros. To examine the problem, you need to enable macro execution. Open the document and allow macros. Select the shape. Press Alt+F11. From the library of the document select makro "mail" and run it. You will notice, that rotation works, but not vertical or horizontal flip. To verify, that it is a problem for custom shapes, you can draw a Bézier-curve for example and apply the macro to the curve. In case you have questions about the macros, please ask.
Created attachment 156707 [details] mirror vertical
Created attachment 156708 [details] rotate by 30deg
Created attachment 156726 [details] Example of mirror by matrix in file format The error is visible too, if the draw:transform attribute contains a matrix, which specifies a reflection. The attached document contains two shape, which have the same geometry. Only that in the draw:transform attribute of the blue shape, the operation "matrix(1 0 0 -1 0cm 0cm)" was added. That results in a mirroring on the x-axis, which is the upper edge of the page on screen.
A patch is for review in https://gerrit.libreoffice.org/85670
Regina Henschel committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/b4a6977e05d87fe0a79b266ec30e4f403404f1b4 tdf#129532 tdf#98839 fixes for mirror of custom shapes It will be available in 7.0.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Still no daily build for Windows for testing. But my work here is finished for now.