I’m trying to create a new filter (and would like to create some pre-set ones) but cannot add the perspective to the richtext filter.
What approach should I use ? Neither CSS 3D transforms nor frei0r.perspective_transform are working
In general do not combine filters into one new ones. Use filter sets. There is a link in the documentation about rich text to the limited subset of HTML4.
Also, there is no such thing as a frei0r.perspective_transformunless you made it. I do not recommend frei0r for new filters; it is too limiting. We are adding support for OpenFX if you want a more capable API. However, for a perspective today you can simply use Corner Pin and make a preset for it.
I think this approximates it:
In the Rich Text, I used the Scroll Up preset, which animates.
If you really want to make a new, more powerful rich text effect then you should be aware that we are using Qt 6, and it has various image processing functions you can do after rendering the text.