When drawing strokes in Grease Pencil, it was always a bit hard
to predict how thick the strokes would be, because there was
no visual reference of the thickness in the cursor.
This patch adds that visual reference. It shows the brush size
as a circle in the draw cursor.
Showing the brush size can be toggled in the Cursor menu
of the Grease Pencil draw tool.
Request in RCS with 26 upvotes for this option:
https://blender.community/c/rightclickselect/0zfbbc
On the technical side: the brush size is calculated
in 3D space and takes zoom level into account, as well as
object/layer transfrom, layer thickness change (gpl->line_change)
and thickness scale (gpd->pixfactor).
Reviewed By: mendio, antoniov
Differential Revision: https://developer.blender.org/D16851
a44c128482