bugfixes

* shift the design to the origin
* don't include a bunch of extra END instructions at the end of a DST

PyEmb.py

@@ -123,6 +123,12 @@ def get_flags(stitch):
     return flags
 
 def write_embroidery_file(file_path, stitches):
+    # Embroidery machines don't care about our canvas size, so we relocate the
+    # design to the origin.  It might make sense to center it about the origin
+    # instead.
+    min_x = min(stitch.x for stitch in stitches)
+    min_y = min(stitch.y for stitch in stitches)
+
     pattern = libembroidery.embPattern_create()
     threads = {}
 
@@ -141,12 +147,18 @@ def write_embroidery_file(file_path, stitches):
             last_color = stitch.color
 
         flags = get_flags(stitch)
-        libembroidery.embPattern_addStitchAbs(pattern, stitch.x, -stitch.y, flags, 0)
+        libembroidery.embPattern_addStitchAbs(pattern, stitch.x - min_x, stitch.y - min_y, flags, 0)
 
         if flags & libembroidery.JUMP:
             # I'm not sure this is right, but this is how the old version did it.
-            libembroidery.embPattern_addStitchAbs(pattern, stitch.x, -stitch.y, flags & ~libembroidery.JUMP, 0)
+            libembroidery.embPattern_addStitchAbs(pattern, stitch.x - min_x, stitch.y - min_y, flags & ~libembroidery.JUMP, 0)
 
-    libembroidery.embPattern_addStitchAbs(pattern, stitch.x, -stitch.y, libembroidery.END, 0)
+    libembroidery.embPattern_addStitchAbs(pattern, stitch.x - min_x, stitch.y - min_y, libembroidery.END, 0)
+
+    # convert from pixels to millimeters
     libembroidery.embPattern_scale(pattern, 1/PIXELS_PER_MM)
+
+    # SVG and embroidery disagree on the direction of the Y axis
+    libembroidery.embPattern_flipVertical(pattern)
+
     libembroidery.embPattern_write(pattern, file_path)