Rendering of contour labels in 3D #322
Description
In 3D mode, contours are rendered as normal, 'filled' labels, breaking our logic to distinguish between foreground and background labels by having a mixture of filled (foreground) and contour (background) labels. The only way to not obscure the foreground labels by (filled) 3D rendered background labels is to set the background opacity to zero, but I find it quite annoying that whenever I switch from 2D to 3D rendering and back, I have to update the background opacity as well. Furthermore, I would like the ortho views (which are still in 2D) to display the contours, and setting the background opacity to zero will make them disappear. So essentially I want to set the background opacity depending on the viewer ndisplay, when we are in contour mode + lineage/group mode.
What is displayed now (in lineage mode, with contours active, and non zero background opacity):
or (with background opacity of 0)
What I want (display contour labels with full transparency in 3D, except for the filled ones):
