default Line Trim Offset
The line part between trim-start, trim-end will be marked as transparent to make a route vanishing effect. The line trim-off offset is based on the whole line range 0.0, 1.0.
The line part between trim-start, trim-end will be marked as transparent to make a route vanishing effect. The line trim-off offset is based on the whole line range 0.0, 1.0.