Support for fontc and crater

Lib/gftools/builder/__init__.py

@@ -7,17 +7,19 @@
 from os import chdir
 from pathlib import Path
 from tempfile import NamedTemporaryFile, gettempdir
-from typing import Any, Dict, List, Union
+from typing import Any, Dict, List, Tuple, Union
 
+from gftools.builder.fontc import FontcArgs
 import networkx as nx
 import strictyaml
 import yaml
 from fontmake.font_project import FontProject
 from ninja import _program
 from ninja.ninja_syntax import Writer, escape_path
+from typing import Union
 
 from gftools.builder.file import File
-from gftools.builder.operations import OperationBase, known_operations
+from gftools.builder.operations import OperationBase, OperationRegistry
 from gftools.builder.operations.copy import Copy
 from gftools.builder.recipeproviders import get_provider
 from gftools.builder.schema import BASE_SCHEMA
@@ -36,7 +38,11 @@ class GFBuilder:
     config: dict
     recipe: Recipe
 
-    def __init__(self, config: Union[dict, str]):
+    def __init__(
+        self,
+        config: Union[dict, str],
+        fontc_args=FontcArgs(None),
+    ):
         if isinstance(config, str):
             parentpath = Path(config).resolve().parent
             with open(config, "r") as file:
@@ -54,7 +60,9 @@ def __init__(self, config: Union[dict, str]):
         else:
             self._orig_config = yaml.dump(config)
             self.config = config
+        fontc_args.modify_config(self.config)
 
+        self.known_operations = OperationRegistry(use_fontc=fontc_args.use_fontc)
         self.writer = Writer(open("build.ninja", "w"))
         self.named_files = {}
         self.used_operations = set([])
@@ -156,9 +164,9 @@ def glyphs_to_ufo(self, source):
 
     def operation_step_to_object(self, step):
         operation = step.get("operation") or step.get("postprocess")
-        if operation not in known_operations:
+        cls = self.known_operations.get(operation)
+        if cls is None:
             raise ValueError(f"Unknown operation {operation}")
-        cls = known_operations[operation]
         if operation not in self.used_operations:
             self.used_operations.add(operation)
             cls.write_rules(self.writer)
@@ -381,8 +389,27 @@ def main(args=None):
         help="Just generate and output recipe from recipe builder",
         action="store_true",
     )
+    parser.add_argument(
+        "--experimental-fontc",
+        help=f"Use fontc instead of fontmake. Argument is path to the fontc executable",
+        type=Path,
+    )
+
+    parser.add_argument(
+        "--experimental-simple-output",
+        help="generate a reduced set of targets, and copy them to the provided directory",
+        type=Path,
+    )
+
+    parser.add_argument(
+        "--experimental-single-source",
+        help="only compile the single named source file",
+        type=str,
+    )
+
     parser.add_argument("config", help="Path to config file or source file", nargs="+")
     args = parser.parse_args(args)
+    fontc_args = FontcArgs(args)
     yaml_files = []
     source_files = []
     for config in args.config:
@@ -404,7 +431,7 @@ def main(args=None):
             raise ValueError("Only one config file can be given for now")
         config = args.config[0]
 
-    pd = GFBuilder(config)
+    pd = GFBuilder(config, fontc_args=fontc_args)
     if args.generate:
         config = pd.config
         config["recipe"] = pd.recipe

Lib/gftools/builder/file.py

@@ -47,6 +47,12 @@ def is_designspace(self):
     def is_font_source(self):
         return self.is_glyphs or self.is_ufo or self.is_designspace
 
+    @cached_property
+    def is_variable(self) -> bool:
+        return (self.is_glyphs and len(self.gsfont.masters) > 1) or (
+            self.is_designspace and len(self.designspace.sources) > 1
+        )
+
     @cached_property
     def gsfont(self):
         if self.is_glyphs:

Lib/gftools/builder/fontc.py

@@ -0,0 +1,81 @@
+"""functionality for running fontc via gftools
+
+gftools has a few special flags that allow it to use fontc, an alternative
+font compiler (https://github.com/googlefonts/fontc).
+
+This module exists to keep the logic related to fontc in one place, and not
+dirty up everything else.
+"""
+
+from argparse import Namespace
+from pathlib import Path
+from typing import Union
+
+from gftools.builder.file import File
+from gftools.builder.operations.fontc import set_global_fontc_path
+
+
+class FontcArgs:
+    # init with 'None' returns a default obj where everything is None
+    def __init__(self, args: Union[Namespace, None]) -> None:
+        if not args:
+            self.simple_output_path = None
+            self.fontc_bin_path = None
+            self.single_source = None
+            return
+        self.simple_output_path = abspath(args.experimental_simple_output)
+        self.fontc_bin_path = abspath(args.experimental_fontc)
+        self.single_source = args.experimental_single_source
+        if self.fontc_bin_path:
+            if not self.fontc_bin_path.is_file():
+                raise ValueError(f"fontc does not exist at {self.fontc_bin_path}")
+            set_global_fontc_path(self.fontc_bin_path)
+
+    @property
+    def use_fontc(self) -> bool:
+        return self.fontc_bin_path is not None
+
+    # update the config dictionary based on our special needs
+    def modify_config(self, config: dict):
+        if self.single_source:
+            filtered_sources = [s for s in config["sources"] if self.single_source in s]
+            n_sources = len(filtered_sources)
+            if n_sources != 1:
+                raise ValueError(
+                    f"--exerimental-single-source {self.single_source} must match exactly one of {config['sources']} (matched {n_sources}) "
+                )
+            config["sources"] = filtered_sources
+
+        if self.fontc_bin_path or self.simple_output_path:
+            # we stash this flag here to pass it down to the recipe provider
+            config["use_fontc"] = self.fontc_bin_path
+            config["buildWebfont"] = False
+            config["buildSmallCap"] = False
+            config["splitItalic"] = False
+            # override config to turn not build instances if we're variable
+            if self.will_build_variable_font(config):
+                config["buildStatic"] = False
+            # if the font doesn't explicitly request CFF, just build TT outlines
+            # if the font _only_ wants CFF outlines, we will try to build them
+            # ( but fail on fontc for now) (but is this even a thing?)
+            elif config.get("buildTTF", True):
+                config["buildOTF"] = False
+        if self.simple_output_path:
+            output_dir = str(self.simple_output_path)
+            # we dump everything into one dir in this case
+            config["outputDir"] = str(output_dir)
+            config["ttDir"] = str(output_dir)
+            config["otDir"] = str(output_dir)
+            config["vfDir"] = str(output_dir)
+
+    def will_build_variable_font(self, config: dict) -> bool:
+        # if config explicitly says dont build variable, believe it
+        if not config.get("buildVariable", True):
+            return False
+
+        source = File(config["sources"][0])
+        return source.is_variable
+
+
+def abspath(path: Union[Path, None]) -> Union[Path, None]:
+    return path.resolve() if path else None

Lib/gftools/builder/operations/__init__.py

@@ -8,6 +8,7 @@
 import sys
 from os.path import dirname
 from tempfile import NamedTemporaryFile
+from typing import Dict
 
 from gftools.builder.file import File
 from gftools.utils import shell_quote
@@ -150,17 +151,46 @@ def variables(self):
         return vars
 
 
-known_operations = {}
+class OperationRegistry:
+    def __init__(self, use_fontc: bool):
+        self.known_operations = get_known_operations()
+        self.use_fontc = use_fontc
 
-for mod in pkgutil.iter_modules([dirname(__file__)]):
-    imp = importlib.import_module("gftools.builder.operations." + mod.name)
-    classes = [
-        (name, cls)
-        for name, cls in inspect.getmembers(sys.modules[imp.__name__], inspect.isclass)
-        if "OperationBase" not in name and issubclass(cls, OperationBase)
-    ]
-    if len(classes) > 1:
-        raise ValueError(
-            f"Too many classes in module gftools.builder.operations.{mod.name}"
-        )
-    known_operations[mod.name] = classes[0][1]
+    def get(self, operation_name: str):
+        if self.use_fontc:
+            if operation_name == "buildVariable":
+                # if we import this at the top level it's a circular import error
+                from .fontc.fontcBuildVariable import FontcBuildVariable
+
+                return FontcBuildVariable
+            if operation_name == "buildTTF":
+                from .fontc.fontcBuildTTF import FontcBuildTTF
+
+            if operation_name == "buildOTF":
+                from .fontc.fontcBuildOTF import FontcBuildOTF
+
+                return FontcBuildOTF
+
+        return self.known_operations.get(operation_name)
+
+
+def get_known_operations() -> Dict[str, OperationBase]:
+    known_operations = {}
+
+    for mod in pkgutil.iter_modules([dirname(__file__)]):
+        if "fontc" in mod.name:
+            continue
+        imp = importlib.import_module("gftools.builder.operations." + mod.name)
+        classes = [
+            (name, cls)
+            for name, cls in inspect.getmembers(
+                sys.modules[imp.__name__], inspect.isclass
+            )
+            if "OperationBase" not in name and issubclass(cls, OperationBase)
+        ]
+        if len(classes) > 1:
+            raise ValueError(
+                f"Too many classes in module gftools.builder.operations.{mod.name}"
+            )
+        known_operations[mod.name] = classes[0][1]
+    return known_operations

Lib/gftools/builder/operations/fontc/__init__.py

@@ -0,0 +1,56 @@
+from pathlib import Path
+from typing import List
+from gftools.builder.operations import OperationBase
+
+_FONTC_PATH = None
+
+
+# should only be called once, from main, before doing anything else. This is a
+# relatively non-invasive way to smuggle this value into FontcOperationBase
+def set_global_fontc_path(path: Path):
+    global _FONTC_PATH
+    assert _FONTC_PATH is None, "set_global_fontc_path should only be called once"
+    _FONTC_PATH = path
+
+
+class FontcOperationBase(OperationBase):
+    @property
+    def variables(self):
+        vars = super().variables
+        vars["fontc_path"] = _FONTC_PATH
+        args = vars.get("args")
+        if args:
+            vars["args"] = rewrite_fontmake_args_for_fontc(args)
+
+        return vars
+
+
+def rewrite_fontmake_args_for_fontc(args: str) -> str:
+    out_args = []
+    arg_list = args.split()
+    # reverse so we can pop in order
+    arg_list.reverse()
+    while arg_list:
+        out_args.append(rewrite_one_arg(arg_list))
+    return " ".join(out_args)
+
+
+# remove next arg from the front of the list and return its fontc equivalent
+def rewrite_one_arg(args: List[str]) -> str:
+    next_ = args.pop()
+    if next_ == "--filter":
+        filter_ = args.pop()
+        # this means 'retain filters defined in UFO', which... do we even support
+        # that in fontc?
+        if filter_ == "...":
+            pass
+        elif filter_ == "FlattenComponentsFilter":
+            return "--flatten-components"
+        elif filter_ == "DecomposeTransformedComponentsFilter":
+            return "--decompose-transformed-components"
+        else:
+            # glue the filter back together for better reporting below
+            next_ = f"{next_} {filter_}"
+    else:
+        raise ValueError(f"unknown fontmake arg '{next_}'")
+    return ""

Lib/gftools/builder/operations/fontc/fontcBuildOTF.py

@@ -0,0 +1,8 @@
+from gftools.builder.operations.fontc import FontcOperationBase
+
+
+class FontcBuildTTF(FontcOperationBase):
+    description = "Build an OTF from a source file (with fontc)"
+    # the '--cff-outlines' flag does not exit in fontc, so this will
+    # error, which we want
+    rule = "$fontc_path -o $out $in $args --cff-outlines"

Lib/gftools/builder/operations/fontc/fontcBuildTTF.py

@@ -0,0 +1,6 @@
+from gftools.builder.operations.fontc import FontcOperationBase
+
+
+class FontcBuildTTF(FontcOperationBase):
+    description = "Build a TTF from a source file (with fontc)"
+    rule = "$fontc_path -o $out $in $args"

Lib/gftools/builder/operations/fontc/fontcBuildVariable.py

@@ -0,0 +1,6 @@
+from gftools.builder.operations.fontc import FontcOperationBase
+
+
+class FontcBuildVariable(FontcOperationBase):
+    description = "Build a variable font from a source file (with fontc)"
+    rule = f"$fontc_path -o $out $in $args"

Lib/gftools/builder/recipeproviders/googlefonts.py

@@ -227,11 +227,7 @@ def build_all_variables(self):
         if not self.config.get("buildVariable", True):
             return
         for source in self.sources:
-            if (
-                (source.is_glyphs and len(source.gsfont.masters) < 2)
-                or source.is_ufo
-                or (source.is_designspace and len(source.designspace.sources) < 2)
-            ):
+            if not source.is_variable:
                 continue
             italic_ds = None
             if self.config["splitItalic"]:
@@ -327,7 +323,8 @@ def build_a_static(self, source: File, instance: InstanceDescriptor, output):
         steps = [
             {"source": source.path},
         ]
-        if not source.is_ufo:
+        # if we're running fontc we skip conversion to UFO
+        if not source.is_ufo and not self.config.get("use_fontc", False):
             instancename = instance.name
             if instancename is None:
                 if not instance.familyName or not instance.styleName: