add info to create charset file

FONT_TO_PY.md

@@ -109,6 +109,13 @@ $ font_to_py.py -k extended FreeSans.ttf 23 my_extended_font.py
  original ASCII set of printable characters. At risk of stating the obvious
  this will only produce useful results if the source font file includes all
  specified glyphs.
+ 
+ A charset file can easilly be created by a one-line Python
+ script. For example, the `latin15` character set file is created by:
+ 
+ ```
+ python3 -c 'print(bytearray([*range(0x20, 0x7F), *range(0xA0, 0xFF)]).decode("iso-8859-15"))' > latin15
+ ```
 
 The -c option may be used to reduce the size of the font file by limiting the
 character set. If the font file is frozen as bytecode this will not reduce RAM

font_to_py/bin_writer.py

@@ -0,0 +1,59 @@
+# Some code adapted from Daniel Bader's work at the following URL
+# https://dbader.org/blog/monochrome-font-rendering-with-freetype-and-python
+# With thanks to Stephen Irons @ironss for various improvements, also to
+# @enigmaniac for ideas around handling `bdf` and `pcf` files.
+
+# The MIT License (MIT)
+#
+# Copyright (c) 2016-2023 Peter Hinch
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+
+import click
+import freetype
+
+from .font import Font
+
+
+# BINARY OUTPUT
+# hmap reverse magic bytes
+# 0    0       0x3f 0xe7
+# 1    0       0x40 0xe7
+# 0    1       0x41 0xe7
+# 1    1       0x42 0xe7
+def write_binary_font(op_path, font_path, height, hmap, reverse):
+    try:
+        fnt = Font(
+            font_path, height, 32, 126, True, None, ""
+        )  # All chars have same width
+    except freetype.ft_errors.FT_Exception:
+        click.echo(f"Can't open {font_path}")
+        return False
+    sig = 1 if hmap else 0
+    if reverse:
+        sig += 2
+    try:
+        with open(op_path, "wb") as stream:
+            data = fnt.build_binary_array(hmap, reverse, sig)
+            stream.write(data)
+    except OSError:
+        click.echo(f"Can't open {op_path} for writing")
+        return False
+    return True

font_to_py/cli.py

@@ -34,7 +34,8 @@ from pathlib import Path
 import click
 import freetype
 
-from .writer import write_binary_font, write_font
+from .bin_writer import write_binary_font
+from .py_writer import write_font
 
 if freetype.version()[0] < 1:
     click.echo("freetype version should be >= 1. Please see FONT_TO_PY.md")

font_to_py/py_writer.py

@@ -0,0 +1,184 @@
+# Some code adapted from Daniel Bader's work at the following URL
+# https://dbader.org/blog/monochrome-font-rendering-with-freetype-and-python
+# With thanks to Stephen Irons @ironss for various improvements, also to
+# @enigmaniac for ideas around handling `bdf` and `pcf` files.
+
+# The MIT License (MIT)
+#
+# Copyright (c) 2016-2023 Peter Hinch
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+import importlib.metadata
+import sys
+from pathlib import Path
+
+import click
+import freetype
+
+from .byte_writer import ByteWriter
+from .font import Font
+
+VERSION = importlib.metadata.version("micropython-font-to-py")
+
+
+# Define a global
+def var_write(stream, name, value):
+    stream.write(f"{name} = {value}\n")
+
+
+STR01 = """# Code generated by font_to_py.
+# Font: {font:s}{charset:s}
+# Cmd: {cmd:s}
+version = '{version:s}'
+
+"""
+
+# Code emitted for charsets spanning a small range of ordinal values
+STR02 = """_mvfont = memoryview(_font)
+_mvi = memoryview(_index)
+ifb = lambda l : l[0] | (l[1] << 8)
+
+def get_ch(ch):
+    oc = ord(ch)
+    ioff = 2 * (oc - {min:d} + 1) if oc >= {min:d} and oc <= {max:d} else 0
+    doff = ifb(_mvi[ioff : ])
+    width = ifb(_mvfont[doff : ])
+"""
+
+# Code emiited for large charsets, assumed by build_arrays() to be sparse.
+# Binary search of sorted sparse index.
+# Offset into data array is saved after dividing by 8
+STRSP = """_mvfont = memoryview(_font)
+_mvsp = memoryview(_sparse)
+ifb = lambda l : l[0] | (l[1] << 8)
+
+def bs(lst, val):
+    while True:
+        m = (len(lst) & ~ 7) >> 1
+        v = ifb(lst[m:])
+        if v == val:
+            return ifb(lst[m + 2:])
+        if not m:
+            return 0
+        lst = lst[m:] if v < val else lst[:m]
+
+def get_ch(ch):
+    doff = bs(_mvsp, ord(ch)) << 3
+    width = ifb(_mvfont[doff : ])
+"""
+
+# Code emitted for horizontally mapped fonts.
+STR02H = """
+    next_offs = doff + 2 + ((width - 1)//8 + 1) * {height:d}
+    return _mvfont[doff + 2:next_offs], {height:d}, width
+
+"""
+
+# Code emitted for vertically mapped fonts.
+STR02V = """
+    next_offs = doff + 2 + (({height:d} - 1)//8 + 1) * width
+    return _mvfont[doff + 2:next_offs], {height:d}, width
+
+"""
+
+# Extra code emitted where -i is specified.
+STR03 = '''
+def glyphs():
+    for c in """{}""":
+        yield c, get_ch(c)
+
+'''
+
+
+def write_func(stream, name, arg):
+    stream.write(f"def {name}():\n    return {arg}\n\n")
+
+
+def write_font(  # noqa: PLR0913
+    op_path,
+    font_path,
+    height,
+    monospaced,
+    hmap,
+    reverse,
+    minchar,
+    maxchar,
+    defchar,
+    charset,
+    iterate,
+    bitmapped,
+):
+    try:
+        fnt = Font(
+            font_path, height, minchar, maxchar, monospaced, defchar, charset, bitmapped
+        )
+    except freetype.ft_errors.FT_Exception:
+        click.echo(f"Can't open {font_path}")
+        return False
+    try:
+        with open(op_path, "w", encoding="utf-8") as stream:
+            write_data(stream, fnt, font_path, hmap, reverse, iterate, charset)
+    except OSError:
+        click.echo(f"Can't open {op_path} for writing")
+        return False
+    return True
+
+
+def write_data(  # noqa: PLR0913
+    stream, fnt, font_path, hmap, reverse, iterate, charset
+):
+    height = fnt.height  # Actual height, not target height
+    minchar = min(fnt.crange)
+    maxchar = max(fnt.crange)
+    st = "" if charset == "" else f" Char set: {charset}"
+    cl = " ".join([str(Path(sys.argv[0]).stem), *sys.argv[1:]])
+    stream.write(
+        STR01.format(font=Path(font_path).stem, charset=st, cmd=cl, version=VERSION)
+    )
+    write_func(stream, "height", height)
+    write_func(stream, "baseline", fnt._max_ascent)
+    write_func(stream, "max_width", fnt.max_width)
+    write_func(stream, "hmap", hmap)
+    write_func(stream, "reverse", reverse)
+    write_func(stream, "monospaced", fnt.monospaced)
+    write_func(stream, "min_ch", minchar)
+    write_func(stream, "max_ch", maxchar)
+    if iterate:
+        stream.write(STR03.format("".join(sorted(fnt.keys()))))
+    data, index, sparse = fnt.build_arrays(hmap, reverse)
+    bw_font = ByteWriter(stream, "_font")
+    bw_font.odata(data)
+    bw_font.eot()
+    if sparse:  # build_arrays() has returned a sparse index
+        bw_sparse = ByteWriter(stream, "_sparse")
+        bw_sparse.odata(sparse)
+        bw_sparse.eot()
+        stream.write(STRSP)
+        click.echo("Sparse")
+    else:
+        bw_index = ByteWriter(stream, "_index")
+        bw_index.odata(index)
+        bw_index.eot()
+        stream.write(STR02.format(min=minchar, max=maxchar))
+        click.echo("Normal")
+    if hmap:
+        stream.write(STR02H.format(height=height))
+    else:
+        stream.write(STR02V.format(height=height))