support apply custom feature file #304

README.md

@@ -138,8 +138,11 @@ There are three kind of options for feature freeze:
 2. `disable`: Remove the features in `cvXX` / `ssXX` / `zero`, which will no longer effect, even if you enable it manually
 3. `ignore`: Do nothing
 
-### Chinese version
+#### Load Custom Feature File
 
+Run `build.py` with `--apply-fea-file` flag, the feature file from [`source/features/{regular,italic}.fea`](./source/features) will be applied into variable font. You can modify it to change all features, e.g. remove some ligatures in `calt`.
+
+### Chinese version
 
 Run `python build.py --cn`, the CN base fonts (about 135 MB) will download from GitHub.
 
@@ -152,9 +155,10 @@ The build script will auto download neccessory assets from GitHub. If you have t
 ### Build Script Usage
 
 ```
-usage: build.py [-h] [-v] [-d] [--debug] [-n] [--feat FEAT] [--hinted] [--no-hinted]
-                [--liga] [--no-liga] [--cn-narrow] [--nerd-font | --no-nerd-font]
-                [--cn | --no-cn] [--cn-both] [--ttf-only] [--cache] [--archive]
+usage: build.py [-h] [-v] [-d] [--debug] [-n] [--feat FEAT] [--apply-fea-file] [--hinted]
+                [--no-hinted] [--liga] [--no-liga] [--cn-narrow]
+                [--nerd-font | --no-nerd-font] [--cn | --no-cn] [--cn-both] [--ttf-only]
+                [--cache] [--archive]
 
 ✨ Builder and optimizer for Maple Mono
 
@@ -168,6 +172,8 @@ Feature Options:
   -n, --normal      Use normal preset, just like `JetBrains Mono` with slashed zero
   --feat FEAT       Freeze font features, splited by `,` (e.g. `--feat
                     zero,cv01,ss07,ss08`). No effect on variable format
+  --apply-fea-file  Load feature file from `source/features/{regular,italic}.fea` to
+                    variable font
   --hinted          Use hinted font as base font
   --no-hinted       Use unhinted font as base font
   --liga            Preserve all the ligatures

build.py

@@ -12,6 +12,7 @@ from os import listdir, makedirs, path, remove, walk, getenv
 from typing import Callable
 from zipfile import ZIP_DEFLATED, ZipFile
 from fontTools.ttLib import TTFont, newTable
+from fontTools.feaLib.builder import addOpenTypeFeatures
 from fontTools.merge import Merger
 from source.py.utils import (
     check_font_patcher,
@@ -79,6 +80,12 @@ def parse_args():
         type=lambda x: x.strip().split(","),
         help="Freeze font features, splited by `,` (e.g. `--feat zero,cv01,ss07,ss08`). No effect on variable format",
     )
+    feature_group.add_argument(
+        "--apply-fea-file",
+        default=None,
+        action="store_true",
+        help="Load feature file from `source/features/{regular,italic}.fea` to variable font",
+    )
     feature_group.add_argument(
         "--hinted",
         dest="hinted",
@@ -177,6 +184,7 @@ class FontConfig:
         self.use_cn_both = None
         self.ttf_only = None
         self.debug = None
+        self.apply_fea_file = None
         # the number of parallel tasks
         # when run in codespace, this will be 1
         self.pool_size = 1 if not getenv("CODESPACE_NAME") else 4
@@ -318,6 +326,9 @@ class FontConfig:
                 if args.ttf_only:
                     self.ttf_only = True
 
+                if args.apply_fea_file:
+                    self.apply_fea_file = True
+
                 name_arr = [word.capitalize() for word in self.family_name.split(" ")]
                 if not self.enable_liga:
                     name_arr.append("NL")
@@ -549,7 +560,11 @@ def rename_glyph_name(
     glyph_names = font.getGlyphOrder()
     extra_names = font["post"].extraNames
     modified = False
-    extra_map = {"uni2047.liga": "question_question.liga", "dotlessi": "idotless"}
+    extra_map = {
+        "uni2047.liga": "question_question.liga",
+        "dotlessi": "idotless",
+        "f_f": "f_f.liga",
+    }
     for i, _ in enumerate(glyph_names):
         old_name = str(glyph_names[i])
 
@@ -920,13 +935,14 @@ def main():
 
     if not should_use_cache or not build_option.has_cache():
         input_files = [
-            f"{build_option.src_dir}/MapleMono-Italic[wght]-VF.ttf",
-            f"{build_option.src_dir}/MapleMono[wght]-VF.ttf",
+            joinPaths(build_option.src_dir, "MapleMono-Italic[wght]-VF.ttf"),
+            joinPaths(build_option.src_dir, "MapleMono[wght]-VF.ttf"),
         ]
         for input_file in input_files:
             font = TTFont(input_file)
 
             # fix auto rename by FontLab
+            print("Fix names")
             rename_glyph_name(
                 font=font,
                 map=match_unicode_names(
@@ -934,6 +950,19 @@ def main():
                 ),
             )
 
+            if font_config.apply_fea_file:
+                fea_path = joinPaths(
+                    build_option.src_dir,
+                    "features/italic.fea"
+                    if "Italic" in input_file
+                    else "features/regular.fea",
+                )
+                print(f"Apply feature file {fea_path} into {path.basename(input_file)}")
+                addOpenTypeFeatures(
+                    font,
+                    fea_path,
+                )
+
             font.save(
                 input_file.replace(build_option.src_dir, build_option.output_variable)
             )