add glyph width checking functionality to ensure monospace compliance #314

build.py

@@ -16,6 +16,7 @@ from fontTools.feaLib.builder import addOpenTypeFeatures
 from fontTools.merge import Merger
 from source.py.utils import (
     check_font_patcher,
+    check_glyph_width,
     download_cn_base_font,
     get_font_forge_bin,
     get_font_name,
@@ -930,6 +931,7 @@ def build_cn(f: str, font_config: FontConfig, build_option: BuildOption):
         }
         cn_font["meta"] = meta
 
+    # check_char_width(cn_font, [0, 600, 1200])
     target_path = joinPaths(
         build_option.output_cn,
         f"{font_config.family_name_compact}-{build_option.cn_suffix_compact}-{style_compact_cn}.ttf",
@@ -955,6 +957,8 @@ def main():
     build_option = BuildOption(font_config)
     build_option.load_cn_dir_and_suffix(font_config.should_build_nf_cn())
 
+    glyph_width = 600
+
     if parsed_args.dry:
         print("font_config:", json.dumps(font_config.__dict__, indent=4))
         if not is_ci():
@@ -1020,6 +1024,8 @@ def main():
                 3,
             )
 
+            check_glyph_width(font, [0, glyph_width])
+
             font.save(
                 input_file.replace(build_option.src_dir, build_option.output_variable)
             )
@@ -1120,6 +1126,13 @@ def main():
 
         build_option.is_cn_built = True
 
+        check_glyph_width(
+            TTFont(
+                joinPaths(build_option.output_cn, listdir(build_option.output_cn)[0])
+            ),
+            [0, glyph_width, glyph_width * 2]
+        )
+
     # write config to output path
     with open(
         joinPaths(build_option.output_dir, "build-config.json"), "w", encoding="utf-8"

source/py/utils.py

@@ -187,3 +187,20 @@ def match_unicode_names(file_path: str) -> dict[str, str]:
             result[unicode_str] = glyph_name
 
     return result
+
+
+def check_glyph_width(font: TTFont, matched_width: tuple[int]):
+    print("Checking glyph width...")
+    result: tuple[str, int] = []
+    for name in font.getGlyphOrder():
+        width, _ = font["hmtx"][name]
+        if width not in matched_width:
+            result.append([name, width])
+
+    if result.__len__() > 0:
+        print("Exist unmatched width:")
+        for item in result:
+            print(f"{item[0]}\t{item[1]}")
+        raise Exception(
+            f"The font may contain glyphs that are not {matched_width} wide, which may broke monospace rule."
+        )