Lettering typographic features (#3466)

* add svg font to layers extension which saves glyph annotations into the glyph name
---------
Co-authored-by: Claudine

1 files changed, 117 insertions, 0 deletions

diff --git a/lib/extensions/lettering_svg_font_to_layers.py b/lib/extensions/lettering_svg_font_to_layers.py
new file mode 100644
index 00000000..d5fc2219
--- /dev/null
+++ b/lib/extensions/lettering_svg_font_to_layers.py
@@ -0,0 +1,117 @@
+#!/usr/bin/env python3
+# coding=utf-8
+#
+# Copyright (C) 2011 Felipe Correa da Silva Sanches <juca@members.fsf.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+#
+# Adapted for the inkstitch lettering module to allow glyph annotations for characters
+# in specific positions or settings. Changes: see git history
+"""Extension for converting svg fonts to layers"""
+
+from inkex import Layer, PathElement, errormsg
+
+from .base import InkstitchExtension
+
+
+class LetteringSvgFontToLayers(InkstitchExtension):
+    """Convert an svg font to layers"""
+
+    def add_arguments(self, pars):
+        pars.add_argument(
+            "--count",
+            type=int,
+            default=30,
+            help="Stop making layers after this number of glyphs.",
+        )
+
+    def flip_cordinate_system(self, elem, emsize, baseline):
+        """Scale and translate the element's path, returns the path object"""
+        path = elem.path
+        path.scale(1, -1, inplace=True)
+        path.translate(0, int(emsize) - int(baseline), inplace=True)
+        return path
+
+    def effect(self):
+        # Current code only reads the first svgfont instance
+        font = self.svg.defs.findone("svg:font")
+        if font is None:
+            return errormsg("There are no svg fonts")
+        # setwidth = font.get("horiz-adv-x")
+        baseline = font.get("horiz-origin-y")
+        if baseline is None:
+            baseline = 0
+
+        guidebase = self.svg.viewbox_height - baseline
+
+        fontface = font.findone("svg:font-face")
+
+        emsize = fontface.get("units-per-em")
+
+        # TODO: should we guarantee that <svg:font horiz-adv-x> equals <svg:font-face units-per-em> ?
+        caps = int(fontface.get("cap-height", 0))
+        xheight = int(fontface.get("x-height", 0))
+        ascender = int(fontface.get("ascent", 0))
+        descender = int(fontface.get("descent", 0))
+
+        self.svg.set("width", emsize)
+        self.svg.namedview.add_guide(guidebase, True, "baseline")
+        self.svg.namedview.add_guide(guidebase - ascender, True, "ascender")
+        self.svg.namedview.add_guide(guidebase - caps, True, "caps")
+        self.svg.namedview.add_guide(guidebase - xheight, True, "xheight")
+        self.svg.namedview.add_guide(guidebase + descender, True, "decender")
+
+        count = 0
+        for glyph in font.findall("svg:glyph"):
+            hide_layer = count != 0
+            self.convert_glyph_to_layer(glyph, emsize, baseline, hide_layer=hide_layer)
+            count += 1
+            if count >= self.options.count:
+                break
+
+    def convert_glyph_to_layer(self, glyph, emsize, baseline, hide_layer):
+        unicode_char = glyph.get("unicode")
+
+        glyph_name = glyph.get("glyph-name").split('.')
+        if unicode_char is None:
+            if len(glyph_name) == 2:
+                unicode_char = glyph_name[0]
+            else:
+                return
+
+        typographic_feature = ''
+        if len(glyph_name) == 2:
+            typographic_feature = glyph_name[1]
+        else:
+            arabic_form = glyph.get('arabic-form', None)
+            if arabic_form is not None and len(arabic_form) > 4:
+                typographic_feature = arabic_form[:4]
+        if typographic_feature:
+            typographic_feature = f".{typographic_feature}"
+
+        layer = self.svg.add(Layer.new(f"GlyphLayer-{unicode_char}{typographic_feature}"))
+
+        # glyph layers (except the first one) are innitially hidden
+        if hide_layer:
+            layer.style["display"] = "none"
+
+        # Using curve description in d attribute of svg:glyph
+        path = layer.add(PathElement())
+        path.path = self.flip_cordinate_system(glyph, emsize, baseline)
+
+
+if __name__ == "__main__":
+    LetteringSvgFontToLayers().run()