change pull_compensation_rails to a continuous balance and fix some edge cases.

lib/elements/satin_column.py

@@ -136,14 +136,13 @@ class SatinColumn(EmbroideryElement):
     @param(
         'pull_compensation_percent',
         _('Pull compensation percentage'),
-        tooltip=_('pull compensation in percentage'),
+        tooltip=_('Additional pull compensation which varries as a percentage of stitch width.'),
         unit='%',
-        type='int',
+        type='float',
         default=0)
     def pull_compensation_percent(self):
         # pull compensation as a percentage of the width
-        return max(self.get_int_param("pull_compensation_percent", 0), 0)
+        return self.get_float_param("pull_compensation_percent", 0)
-
     @property
     @param(
         'pull_compensation_mm',
@@ -161,15 +160,14 @@ class SatinColumn(EmbroideryElement):
 
     @property
     @param(
-        'pull_compensation_rails',
+        'pull_compensation_balance',
-        _('Apply pull compensation to '),
+        _('Pull compensation balance'),
-        tooltip=_('decide wether the pull compensations should be applied to both side  or only to a given one'),
+        tooltip=_('Percentage of pull compensation which gets applied to second rail (50% is centered).'),
-        type='dropdown',
+        unit='%',
-        options=[_("Both rails"), _("First rail only"), _("Second rail only")],
+        type='float',
-        default=0)
+        default=50)
-    def pull_compensation_rails(self):
+    def pull_compensation_balance(self):
-        # 0=Both  | 1 = First Rail | 2 = Second Rail
+        return min(100, max(0, self.get_float_param("pull_compensation_balance", 50)))
-        return self.get_int_param("pull_compensation_rails", 0)
 
     @property
     @param('contour_underlay', _('Contour underlay'), type='toggle', group=_('Contour Underlay'))
@@ -643,41 +641,31 @@ class SatinColumn(EmbroideryElement):
         center_walk, _ = self.plot_points_on_rails(self.zigzag_spacing, -100000)
         return shgeo.LineString(center_walk)
 
-    def offset_points(self, pos1, pos2, offset, offset_percent=0, offset_rails=0):
+    def offset_points(self, pos1, pos2, offset_px, offset_prop=0, offset_balance=0.5):
         # Expand or contract two points about their midpoint.  This is
         # useful for pull compensation and insetting underlay.
 
         distance = (pos1 - pos2).length()
-        offset_px = 0
-        if offset:
-            offset_px += offset
-        if offset_percent:
-            offset_px += ((offset_percent / 100) * distance)
 
         if distance < 0.0001:
             # if they're the same point, we don't know which direction
             # to offset in, so we have to just return the points
             return pos1, pos2
 
+        # calculate the offset for each side
+        offset_total = offset_px + (offset_prop * distance)
+        inv_offset_balance = 1 - offset_balance
+        offset1 = offset_total * inv_offset_balance
+        offset2 = offset_total * offset_balance
+
         # don't contract beyond the midpoint, or we'll start expanding
-        if offset_px < -distance / 2.0:
+        if offset1 < -distance * inv_offset_balance:
-            offset_px = -distance / 2.0
+            offset1 = -distance * inv_offset_balance
+        if offset2 < -distance * offset_balance:
+            offset2 = -distance * offset_balance
 
-        # chose how to apply on the rails
+        pos1 = pos1 + (pos1 - pos2).unit() * offset1
-
+        pos2 = pos2 + (pos2 - pos1).unit() * offset2
-        coeff1 = 1
-        coeff2 = 1
-
-        if offset_rails == 1:
-            coeff1 = 2
-            coeff2 = 0
-
-        if offset_rails == 2:
-            coeff1 = 0
-            coeff2 = 2
-
-        pos1 = pos1 + (pos1 - pos2).unit() * offset_px * coeff1
-        pos2 = pos2 + (pos2 - pos1).unit() * offset_px * coeff2
 
         return pos1, pos2
 
@@ -714,13 +702,13 @@ class SatinColumn(EmbroideryElement):
                 distance_remaining -= segment_length
                 pos = segment_end
 
-    def plot_points_on_rails(self, spacing, offset, offset_percent=0, offset_rails=0):
+    def plot_points_on_rails(self, spacing, offset_px=0, offset_prop=0, offset_balance=0.5):
         # Take a section from each rail in turn, and plot out an equal number
         # of points on both rails.  Return the points plotted. The points will
         # be contracted or expanded by offset using self.offset_points().
 
         def add_pair(pos0, pos1):
-            pos0, pos1 = self.offset_points(pos0, pos1, offset, offset_percent, offset_rails)
+            pos0, pos1 = self.offset_points(pos0, pos1, offset_px, offset_prop, offset_balance)
             points[0].append(pos0)
             points[1].append(pos1)
 
@@ -878,8 +866,10 @@ class SatinColumn(EmbroideryElement):
         # print >> dbg, "satin", self.zigzag_spacing, self.pull_compensation
 
         patch = StitchGroup(color=self.color)
-        sides = self.plot_points_on_rails(self.zigzag_spacing, self.pull_compensation, self.pull_compensation_percent,
+
-                                          self.pull_compensation_rails)
+        # pull compensation is automatically converted from mm to pixels by get_float_param
+        sides = self.plot_points_on_rails(self.zigzag_spacing, self.pull_compensation, self.pull_compensation_percent/100,
+                                          self.pull_compensation_balance/100)
 
         if self.max_stitch_length:
             return self.do_split_stitch(patch, sides)
@@ -909,7 +899,7 @@ class SatinColumn(EmbroideryElement):
 
         patch = StitchGroup(color=self.color)
 
-        sides = self.plot_points_on_rails(self.zigzag_spacing, self.pull_compensation, self.pull_compensation_percent, self.pull_compensation_rails)
+        sides = self.plot_points_on_rails(self.zigzag_spacing, self.pull_compensation, self.pull_compensation_percent/100, self.pull_compensation_balance/100)
 
         # "left" and "right" here are kind of arbitrary designations meaning
         # a point from the first and second rail respectively

lib/svg/tags.py

@@ -117,7 +117,7 @@ inkstitch_attribs = [
     'e_stitch',
     'pull_compensation_mm',
     'pull_compensation_percent',
-    'pull_compensation_rails',
+    'pull_compensation_balance',
     'stroke_first',
     # stitch_plan
     'invisible_layers',