Add randomized running and fill stitches (#2830)

Add a mode to running stitch that uses randomized phase and stitch length instead of even spacing. This greatly reduces moire effects when stitching closely-spaced curves in running-stitch-based fills.

Add option for randomized running stitch to:

    ripple stitch
    circular fill
    contour fill
    guided fill
    auto-fill

When is randomization is not selected, ripple stitch will use even running stitch when staggers are set to 0 (default) and the stagger algorithm from guided fill (which does not look nice with a stagger period of 0) when staggers is nonzero.

Also includes fix for satin contour underlays (missing tolerance default) mentioned in #2814. This sets the default tolerance to 0.2mm, which is the largest tolerance guaranteed to be backwards-compatible with existing designs using the default inset of 0.4mm.

Original commits:
* fix satin underlay tolerance default
* Add randomized running stitch, make available in ripple stitch, circular, and contour
* add randomized guided fill
* make ripple stitch use even stitching when not staggering or randomizing.
* add random auto-fill and switch jitter parameter to a percentage (matches satin)
* fix comments

1 files changed, 10 insertions, 8 deletions

diff --git a/lib/elements/satin_column.py b/lib/elements/satin_column.py
index a33afb8b..9cf7bc73 100644
--- a/lib/elements/satin_column.py
+++ b/lib/elements/satin_column.py
@@ -372,10 +372,11 @@ class SatinColumn(EmbroideryElement):
         unit='mm',
         group=_('Contour Underlay'),
         type='float',
+        default=0.2,
     )
     def contour_underlay_stitch_tolerance(self):
-        tolerance = self.get_float_param("contour_underlay_stitch_tolerance_mm", self.contour_underlay_stitch_length)
-        return max(tolerance, 0.01)
+        tolerance = self.get_float_param("contour_underlay_stitch_tolerance_mm", 0.2)
+        return max(tolerance, 0.01 * PIXELS_PER_MM)  # sanity check to prevent crash from excessively-small values
 
     @property
     @param('contour_underlay_inset_mm',
@@ -428,11 +429,12 @@ class SatinColumn(EmbroideryElement):
         ),
         unit='mm',
         group=_('Center-Walk Underlay'),
-        type='float'
+        type='float',
+        default=0.2
     )
     def center_walk_underlay_stitch_tolerance(self):
-        tolerance = self.get_float_param("center_walk_underlay_stitch_tolerance_mm", self.contour_underlay_stitch_length)
-        return max(tolerance, 0.01)
+        tolerance = self.get_float_param("center_walk_underlay_stitch_tolerance_mm", 0.2)
+        return max(tolerance, 0.01 * PIXELS_PER_MM)
 
     @property
     @param('center_walk_underlay_repeats',
@@ -1171,12 +1173,12 @@ class SatinColumn(EmbroideryElement):
             self.contour_underlay_stitch_tolerance,
             -self.contour_underlay_inset_px, -self.contour_underlay_inset_percent/100)
 
-        first_side = running_stitch.running_stitch(
+        first_side = running_stitch.even_running_stitch(
             [points[0] for points in pairs],
             self.contour_underlay_stitch_length,
             self.contour_underlay_stitch_tolerance
         )
-        second_side = running_stitch.running_stitch(
+        second_side = running_stitch.even_running_stitch(
             [points[1] for points in pairs],
             self.contour_underlay_stitch_length,
             self.contour_underlay_stitch_tolerance
@@ -1209,7 +1211,7 @@ class SatinColumn(EmbroideryElement):
             (0, 0), inset_prop)
 
         points = [points[0] for points in pairs]
-        stitches = running_stitch.running_stitch(points, self.center_walk_underlay_stitch_length, self.center_walk_underlay_stitch_tolerance)
+        stitches = running_stitch.even_running_stitch(points, self.center_walk_underlay_stitch_length, self.center_walk_underlay_stitch_tolerance)
 
         for i in range(self.center_walk_underlay_repeats - 1):
             if i % 2 == 0: