basic lettering (#344)

Can handle multiple lines of text and routes the stitching in alternating directions on each line.

1 files changed, 86 insertions, 0 deletions

diff --git a/lib/lettering/font_variant.py b/lib/lettering/font_variant.py
new file mode 100644
index 00000000..445946e2
--- /dev/null
+++ b/lib/lettering/font_variant.py
@@ -0,0 +1,86 @@
+# -*- coding: UTF-8 -*-
+
+import os
+import inkex
+import simplestyle
+
+from ..svg.tags import INKSCAPE_GROUPMODE, INKSCAPE_LABEL
+from .glyph import Glyph
+
+
+class FontVariant(object):
+    """Represents a single variant of a font.
+
+    Each font may have multiple variants for left-to-right, right-to-left,
+    etc.  Each variant has a set of Glyphs, one per character.
+
+    A FontVariant instance can be accessed as a dict by using a unicode
+    character as a key.
+
+    Properties:
+      path    -- the path to the directory containing this font
+      variant -- the font variant, specified using one of the constants below
+      glyphs  -- a dict of Glyphs, with the glyphs' unicode characters as keys.
+    """
+
+    # We use unicode characters rather than English strings for font file names
+    # in order to be more approachable for languages other than English.
+    LEFT_TO_RIGHT = u"→"
+    RIGHT_TO_LEFT = u"←"
+    TOP_TO_BOTTOM = u"↓"
+    BOTTOM_TO_TOP = u"↑"
+    VARIANT_TYPES = (LEFT_TO_RIGHT, RIGHT_TO_LEFT, TOP_TO_BOTTOM, BOTTOM_TO_TOP)
+
+    @classmethod
+    def reversed_variant(cls, variant):
+        if variant == cls.LEFT_TO_RIGHT:
+            return cls.RIGHT_TO_LEFT
+        elif variant == cls.RIGHT_TO_LEFT:
+            return cls.LEFT_TO_RIGHT
+        elif variant == cls.TOP_TO_BOTTOM:
+            return cls.BOTTOM_TO_TOP
+        elif variant == cls.BOTTOM_TO_TOP:
+            return cls.TOP_TO_BOTTOM
+        else:
+            return None
+
+    def __init__(self, font_path, variant, default_glyph=None):
+        self.path = font_path
+        self.variant = variant
+        self.default_glyph = default_glyph
+        self.glyphs = {}
+        self._load_glyphs()
+
+    def _load_glyphs(self):
+        svg_path = os.path.join(self.path, u"%s.svg" % self.variant)
+        svg = inkex.etree.parse(svg_path)
+
+        glyph_layers = svg.xpath(".//svg:g[starts-with(@inkscape:label, 'GlyphLayer-')]", namespaces=inkex.NSS)
+        for layer in glyph_layers:
+            self._clean_group(layer)
+            layer.attrib[INKSCAPE_LABEL] = layer.attrib[INKSCAPE_LABEL].replace("GlyphLayer-", "", 1)
+            glyph_name = layer.attrib[INKSCAPE_LABEL]
+            self.glyphs[glyph_name] = Glyph(layer)
+
+    def _clean_group(self, group):
+        # We'll repurpose the layer as a container group labelled with the
+        # glyph.
+        del group.attrib[INKSCAPE_GROUPMODE]
+
+        style_text = group.get('style')
+
+        if style_text:
+            # The layer may be marked invisible, so we'll clear the 'display'
+            # style.
+            style = simplestyle.parseStyle(group.get('style'))
+            style.pop('display')
+            group.set('style', simplestyle.formatStyle(style))
+
+    def __getitem__(self, character):
+        if character in self.glyphs:
+            return self.glyphs[character]
+        else:
+            return self.glyphs.get(self.default_glyph, None)
+
+    def __contains__(self, character):
+        return character in self.glyphs