1 files changed, 144 insertions, 0 deletions
diff --git a/lib/extensions/lettering_along_path.py b/lib/extensions/lettering_along_path.py
new file mode 100644
index 00000000..63ffc817
--- /dev/null
+++ b/lib/extensions/lettering_along_path.py
@@ -0,0 +1,144 @@
+# Authors: see git history
+#
+# Copyright (c) 2021 Authors
+# Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.
+
+import json
+import sys
+from math import atan2, degrees
+
+from inkex import Boolean, Transform, errormsg
+from shapely.ops import substring
+
+from ..elements import Stroke
+from ..i18n import _
+from ..svg import get_correction_transform
+from ..svg.tags import EMBROIDERABLE_TAGS, INKSTITCH_LETTERING, SVG_GROUP_TAG
+from ..utils import DotDict
+from ..utils import Point as InkstitchPoint
+from .base import InkstitchExtension
+
+
+class LetteringAlongPath(InkstitchExtension):
+    '''
+    This extension aligns an Ink/Stitch Lettering group along a path
+    '''
+    def __init__(self, *args, **kwargs):
+        InkstitchExtension.__init__(self, *args, **kwargs)
+        self.arg_parser.add_argument("-o", "--options", type=str, default=None, dest="page_1")
+        self.arg_parser.add_argument("-i", "--info", type=str, default=None, dest="page_2")
+        self.arg_parser.add_argument("-s", "--stretch-spaces", type=Boolean, default=False, dest="stretch_spaces")
+
+    def effect(self):
+        # we ignore everything but the first path/text
+        text, path = self.get_selection()
+        self.load_settings(text)
+
+        glyphs = [glyph for glyph in text.iterdescendants(SVG_GROUP_TAG) if len(glyph.label) == 1]
+        if not glyphs:
+            errormsg(_("The text doesn't contain any glyphs."))
+            sys.exit(1)
+
+        path = Stroke(path).as_multi_line_string().geoms[0]
+        path_length = path.length
+
+        # overall bounding box - get from direct glyph parent
+        text_bbox = glyphs[0].getparent().bounding_box()
+        text_y = text_bbox.bottom
+
+        if self.options.stretch_spaces:
+            text_content = self.settings["text"]
+            space_indices = [i for i, t in enumerate(text_content) if t == " "]
+            text_width = text_bbox.width
+
+            if len(text_content) - 1 != 0:
+                stretch_space = (path_length - text_width) / (len(text_content) - 1)
+            else:
+                stretch_space = 0
+        else:
+            stretch_space = 0
+            space_indices = []
+
+        self.transform_glyphs(glyphs, path, stretch_space, space_indices, text_y)
+
+    def transform_glyphs(self, glyphs, path, stretch_space, space_indices, text_y):
+        text_scale = Transform(f'scale({self.settings["scale"] / 100})')
+        distance = 0
+        old_bbox = None
+        i = 0
+
+        for glyph in glyphs:
+            # dimensions
+            bbox = glyph.bounding_box()
+            left = bbox.left
+            width = bbox.width
+
+            # adjust position
+            if old_bbox:
+                right = old_bbox.right
+                distance += left - right + stretch_space
+
+            if self.options.stretch_spaces and i in space_indices:
+                distance += stretch_space
+                i += 1
+
+            new_distance = distance + width
+
+            # calculate and apply transform
+            first = substring(path, distance, distance)
+            last = substring(path, new_distance, new_distance)
+
+            angle = degrees(atan2(last.y - first.y, last.x - first.x)) % 360
+            translate = InkstitchPoint(first.x, first.y) - InkstitchPoint(left, text_y)
+
+            transform = Transform(f"rotate({angle}, {first.x}, {first.y}) translate({translate.x} {translate.y})")
+            correction_transform = Transform(get_correction_transform(glyph))
+            glyph.transform = correction_transform @ transform @ glyph.transform @ text_scale
+
+            # set values for next iteration
+            distance = new_distance
+            old_bbox = bbox
+            i += 1
+
+    def load_settings(self, text):
+        """Load the settings saved into the text element"""
+
+        self.settings = DotDict({
+            "text": "",
+            "back_and_forth": False,
+            "font": None,
+            "scale": 100,
+            "trim_option": 0
+        })
+
+        if INKSTITCH_LETTERING in text.attrib:
+            try:
+                self.settings.update(json.loads(text.get(INKSTITCH_LETTERING)))
+            except (TypeError, ValueError):
+                pass
+
+    def get_selection(self):
+        groups = list()
+        paths = list()
+
+        for node in self.svg.selection:
+            lettering = False
+            if node.tag == SVG_GROUP_TAG and INKSTITCH_LETTERING in node.attrib:
+                groups.append(node)
+                lettering = True
+                continue
+
+            for group in node.iterancestors(SVG_GROUP_TAG):
+                if INKSTITCH_LETTERING in group.attrib:
+                    groups.append(group)
+                    lettering = True
+                    break
+
+            if not lettering and node.tag in EMBROIDERABLE_TAGS:
+                paths.append(node)
+
+        if not groups or not paths:
+            errormsg(_("Please select one path and one Ink/Stitch lettering group."))
+            sys.exit(1)
+
+        return [groups[0], paths[0]]