1 files changed, 43 insertions, 0 deletions
diff --git a/lib/stitch_plan/stop.py b/lib/stitch_plan/stop.py
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+++ b/lib/stitch_plan/stop.py
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+def process_stop(color_block):
+    """Handle the "stop after" checkbox.
+
+    The user wants the machine to pause after this patch.  This can
+    be useful for applique and similar on multi-needle machines that
+    normally would not stop between colors.
+
+    In machine embroidery files, there's no such thing as an actual
+    "STOP" instruction.  All that exists is a "color change" command
+    (which libembroidery calls STOP just to be confusing).
+
+    On multi-needle machines, the user assigns needles to the colors in
+    the design before starting stitching.  C01, C02, etc are normal
+    needles, but C00 is special.  For a block of stitches assigned
+    to C00, the machine will continue sewing with the last color it
+    had and pause after it completes the C00 block.
+
+    That means we need to add an artificial color change instruction
+    shortly before the current stitch so that the user can set that color
+    block to C00.  We'll go back 3 stitches and mark the start of the C00
+    block:
+    """
+
+    if len(color_block.stitches) >= 3:
+        # make a copy of the stitch and set it as a color change
+        stitch = color_block.stitches[-3].copy()
+        stitch.color_change = True
+
+        # mark this stitch as a "stop" so that we can avoid
+        # adding tie stitches in ties.py
+        stitch.stop = True
+
+        # insert it after the stitch
+        color_block.stitches.insert(-2, stitch)
+
+    # and also add a color change on this stitch, completing the C00
+    # block:
+
+    stitch = color_block.stitches[-1].copy()
+    stitch.color_change = True
+    color_block.add_stitch(stitch)
+
+    # reference for the above: https://github.com/lexelby/inkstitch/pull/29#issuecomment-359175447