Ninja runner for addition of COLR to ot-svg, svg glyph reduction.

src/nanoemoji/extract_svgs.py

@@ -0,0 +1,49 @@
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Helpers for extracting svg files from the SVG table."""
+
+
+import copy
+from fontTools import ttLib
+from picosvg.svg import SVG
+from picosvg.svg_meta import strip_ns
+from typing import Iterable, Tuple
+
+
+def _remove_glyph_elements(svg: SVG, gids_to_remove: Iterable[int]) -> SVG:
+    """Strip out unwanted glyph roots.
+
+    We do NOT try to strip unused shared content; that is left for others,
+    e.g. picosvg.
+    """
+    svg = copy.deepcopy(svg)
+    for gid in gids_to_remove:
+        results = svg.xpath(f"svg:*[@id='glyph{gid}']")
+        for result in results:
+            parent = result.getparent()
+            if parent is not None:
+                parent.remove(result)
+    return svg
+
+
+def svg_glyphs(font: ttLib.TTFont) -> Iterable[Tuple[int, SVG]]:
+    for raw_svg, min_gid, max_gid in font["SVG "].docList:
+        gids = set(range(min_gid, max_gid + 1))
+        svg = SVG.fromstring(raw_svg)
+        for gid in gids:
+            svg_for_gid = svg
+            if len(gids) > 1:
+                svg_for_gid = _remove_glyph_elements(svg_for_gid, gids - {gid})
+            yield (gid, svg_for_gid)

src/nanoemoji/extract_svgs_from_otsvg.py

@@ -20,6 +20,7 @@
 from lxml import etree
 from nanoemoji import codepoints
 from nanoemoji.color_glyph import map_viewbox_to_otsvg_space
+from nanoemoji.extract_svgs import svg_glyphs
 from nanoemoji import util
 import os
 import shutil
@@ -62,8 +63,7 @@ def main(argv):
     # So use the font height (global) and width (per glyph) as the svg viewbox
     height = ascender - descender
 
-    for raw_svg, min_gid, max_gid in font["SVG "].docList:
-        svg = SVG.fromstring(raw_svg)
+    for gid, svg in svg_glyphs(font):
         svg_defs = etree.Element("defs")
         svg_g = etree.Element("g")
         svg_g.attrib["transform"] = f"translate(0, {ascender})"
@@ -77,14 +77,13 @@ def main(argv):
         svg.svg_root.append(svg_defs)
         svg.svg_root.append(svg_g)
 
-        for gid in range(min_gid, max_gid + 1):
-            glyph_name = font.getGlyphName(gid)
-            width, _ = metrics[glyph_name]
-            svg.svg_root.attrib["viewBox"] = f"0 0 {width} {height}"
-            dest_file = out_dir / f"{gid}.svg"
-            with open(dest_file, "w") as f:
-                f.write(svg.tostring(pretty_print=True))
-            logging.debug("Wrote %s", dest_file)
+        glyph_name = font.getGlyphName(gid)
+        width, _ = metrics[glyph_name]
+        svg.svg_root.attrib["viewBox"] = f"0 0 {width} {height}"
+        dest_file = out_dir / f"{gid}.svg"
+        with open(dest_file, "w") as f:
+            f.write(svg.tostring(pretty_print=True))
+        logging.debug("Wrote %s", dest_file)
 
 
 if __name__ == "__main__":

src/nanoemoji/glue_together.py

@@ -45,7 +45,6 @@ def _collect_glyphs(paint):
         record.Paint.traverse(donor["COLR"].table, _collect_glyphs)
 
     for glyph_name in _glyphs_to_copy:
-        print("Copy glyph", glyph_name)
         target["glyf"].glyphs[glyph_name] = donor["glyf"].glyphs[glyph_name]
         target["hmtx"].metrics[glyph_name] = donor["hmtx"].metrics[glyph_name]
 

src/nanoemoji/maximum_color.py

@@ -0,0 +1,179 @@
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Generates color tables to provide support for a wide range of browsers.
+
+Requires input font have vector color capability, that is either an SVG table
+or COLR/CPAL.
+
+https://www.youtube.com/watch?v=HLddvNiXym4
+
+Sample usage:
+
+python -m nanoemoji.maximum_color MySvgFont.ttf"""
+from absl import app
+from absl import logging
+from fontTools import ttLib
+from nanoemoji.extract_svgs import svg_glyphs
+from nanoemoji.ninja import (
+    build_dir,
+    gen_ninja,
+    maybe_run_ninja,
+    module_rule,
+    rel_build,
+    NinjaWriter,
+)
+from nanoemoji.util import only
+from pathlib import Path
+
+
+_SVG2COLR_GLYPHMAP = "svg2colr.glyphmap"
+_SVG2COLR_CONFIG = "svg2colr.toml"
+
+
+def _vector_color_table(font: ttLib.TTFont) -> str:
+    has_svg = "SVG " in font
+    has_colr = "COLR" in font
+    if has_svg == has_colr:
+        raise ValueError("Must have one of COLR, SVG")
+
+    if has_svg:
+        return "SVG "
+    if has_colr:
+        return "COLR"
+
+    raise ValueError("Impossible")
+
+
+def svg_extract_dir() -> Path:
+    return build_dir() / "svg_dump"
+
+
+def picosvg_dir() -> Path:
+    return build_dir() / "picosvg"
+
+
+def picosvg_dest(input_svg: Path) -> Path:
+    return picosvg_dir() / input_svg.name
+
+
+def _write_preamble(nw: NinjaWriter, input_font: Path):
+    module_rule(
+        nw,
+        "extract_svgs_from_otsvg",
+        f"--output_dir {rel_build(svg_extract_dir())} $in $out",
+    )
+    nw.newline()
+
+    module_rule(nw, "write_glyphmap_for_glyph_svgs", "$in > $out")
+    nw.newline()
+
+    module_rule(nw, "write_config_for_glyph_svgs", "$in $out")
+    nw.newline()
+
+    module_rule(
+        nw,
+        "write_font",
+        f"--glyphmap_file {_SVG2COLR_GLYPHMAP} --config_file {_SVG2COLR_CONFIG} --output_file $out",
+        rule_name="write_colr_font_from_svg_dump",
+    )
+    nw.newline()
+
+    nw.rule(
+        f"picosvg",
+        f"picosvg  --output_file $out $in",
+    )
+    nw.newline()
+
+    module_rule(
+        nw,
+        "glue_together",
+        f"--color_table COLR --target_font {rel_build(input_font)} --donor_font $in --output_file $out",
+        rule_name="copy_colr_from_svg2colr",
+    )
+    nw.newline()
+
+
+def _write_svg_extract(nw: NinjaWriter, input_font: Path, font: ttLib.TTFont):
+    # extract the svgs
+    svg_extracts = [
+        rel_build(svg_extract_dir() / f"{gid}.svg") for gid, _ in svg_glyphs(font)
+    ]
+    nw.build(svg_extracts, "extract_svgs_from_otsvg", input_font)
+    nw.newline()
+
+    # picosvg them
+    picosvgs = [rel_build(picosvg_dest(s)) for s in svg_extracts]
+    for svg_extract, picosvg in zip(svg_extracts, picosvgs):
+        nw.build(picosvg, "picosvg", svg_extract)
+    nw.newline()
+
+    # make a glyphmap
+    nw.build(
+        _SVG2COLR_GLYPHMAP, "write_glyphmap_for_glyph_svgs", picosvgs + [input_font]
+    )
+    nw.newline()
+
+    # make a config
+    nw.build(_SVG2COLR_CONFIG, "write_config_for_glyph_svgs", input_font)
+    nw.newline()
+
+    # generate a new font with COLR glyphs that use the same names as the original
+    nw.build(
+        "colr_from_svg.ttf",
+        "write_colr_font_from_svg_dump",
+        [_SVG2COLR_GLYPHMAP, _SVG2COLR_CONFIG],
+    )
+    nw.newline()
+
+    # stick our shiny new COLR table onto the input font and declare victory
+    nw.build(
+        input_font.name,
+        "copy_colr_from_svg2colr",
+        "colr_from_svg.ttf",
+    )
+    nw.newline()
+
+
+def main(argv):
+    if len(argv) != 2:
+        raise ValueError("Must have one argument, a font file")
+
+    input_font = Path(argv[1])
+    assert input_font.is_file()
+    font = ttLib.TTFont(input_font)
+
+    build_file = build_dir() / "build.ninja"
+    build_dir().mkdir(parents=True, exist_ok=True)
+
+    print(build_dir())  # TEMPORARY
+
+    color_table = _vector_color_table(font)
+
+    if gen_ninja():
+        logging.info(f"Generating {build_file.relative_to(build_dir())}")
+        with open(build_file, "w") as f:
+            nw = NinjaWriter(f)
+            _write_preamble(nw, input_font)
+
+            if color_table == "COLR":
+                raise NotImplementedError("Conversion from COLR coming soon")
+            else:
+                _write_svg_extract(nw, input_font, font)
+
+    maybe_run_ninja(build_file)
+
+
+if __name__ == "__main__":
+    app.run(main)