Equal length dashed lines while using 'segments_to_lines' in QGIS

Question

I want to create tapered lines with a dashed line stroke (to style intermittent streams). I followed this tutorial to create the taperered lines, basically using Geometry generator with the expression segments_to_lines($geometry) and added the following stroke width expression:

CASE
  WHEN @geometry_part_num < 15 THEN  (0.222750 * (@geometry_part_num / 15))
  ELSE 0.22750
END

The result is as it is supposed to be:

But when I style the tapered lines with a dashed line stroke the dashes (and spaces) have very varied lengths (I assume due to segments_to_lines($geometry)): For reference, this is how the dashed lines are supposed to look:

Does anybody have an idea how I could achieve this effect while having the line tapered?

Answer 1

This effect occurs because of the different spacing between the line vertices. Try using the Densify by interval tool to make the vertices more evenly spaced on the line. Some test results are shown in the images below.

As commented by @sidapo_cartisan expression may be inserted directly in the geometry generator code: segments_to_lines( densify_by_distance($geometry, distance))

               Original line                            Densified line