pimoroni-pico/examples/badger2040/hershey_font_converter/convert.py

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4.9 KiB
Python
Executable File

#!/usr/bin/env python3
# converts Hershey fonts into a format easier to consume by the Badger2040
# e-ink badge library - the result can be piped directly into a .hpp file.
import argparse
from pathlib import Path
parser = argparse.ArgumentParser(
description="Converts Hershey fonts into the format used by Badger2040."
)
parser.add_argument("file", nargs="+", help="input files to convert")
options = parser.parse_args()
def convert_font(data):
# parse hershey font data file, the file format contains one record per
# character with the format:
#
# 2761 8MXP[OZPYQZQ[P]N_
#
# first 5 characters: represent the character id (or a dummy value
# of 12345). if it is a character id then a separate file contains the
# mapping information to convert that into an ascii table entry. if all of
# the ids are 12345 then it seems that the files contain 95 entries that
# start from ascii character 32 (space) in order
#
# next 3 characters: number of vertices (including special left/right
# bounds value)
#
# next 2 characters: represent the "left" and "right" offsets for this
# character, to convert you must subtract 'R' from them. this pair counts
# as the first "vertex"
#
# subsequent pairs of characters: represent each vertex, as before converted
# into numbers by subtracting 'R'. there are vertex count (-1) of these
#
# note! within the vertex data can be extra newline characters which must
# be ignored.
vertex_data = []
char_data = {}
auto_char_code = 0
# we'll loop, extracting one character per iteration, until all of the
# data is consumed
while len(data) > 0:
char_code = auto_char_code
auto_char_code += 1
# extract vertex count
vertex_count = int(data[5:8])
vertex_count -= 1 # remove one for the bounds data
# extract bounds
left = ord(data[8:9]) - ord("R")
right = ord(data[9:10]) - ord("R")
char_data[char_code] = {
"width": right - left,
"vertex_count": vertex_count,
"first_vertex_offset": len(vertex_data),
}
# work out expected total length of character data
char_data_len = 10 + (vertex_count * 2)
# if there are any newlines within this data then remove them before we
# move on the parse the vertices
while data.find("\n", char_data_len) != -1:
data = data.replace("\n", "", 1)
for i in range(0, vertex_count):
offset = 10 + (i * 2)
if data[offset:offset + 2] == " R":
# pen up for one
x = -128
y = -128
else:
x = ord(data[offset + 0:offset + 1]) - ord("R") - left
y = ord(data[offset + 1:offset + 2]) - ord("R")
vertex_data.append(str(x))
vertex_data.append(str(y))
data = data[char_data_len:]
font_name = Path(input_filename).stem
# create code for all of the vertices
vertex_code = """\
static const int8_t {font_name}_vertices[{count}] = {{
{vertices}
}};
""".format(
font_name=font_name, count=len(vertex_data), vertices=", ".join(vertex_data)
)
# create code for chars and font
#
# struct hershey_font_glyph_t {
# uint32_t width; // character width
# uint32_t vertex_count; // number of vertices
# int8_t *vertices; // vertex data (indices: even = x, odd = y)
# };
chars = []
for i in range(0, 95):
if i in char_data:
chars.append(
" {{.width={width}, .vertex_count={vertex_count}, .vertices=&{font_name}_vertices[{offset}]}}".format(
width=char_data[i]["width"],
vertex_count=char_data[i]["vertex_count"],
font_name=font_name,
offset=char_data[i]["first_vertex_offset"],
)
)
else:
chars.append(" {.width=0, .vertex_count=0, .vertices=nullptr}")
# struct hershey_font_t {
# hershey_font_glyph_t chars[95];
# };
font_code = """\
static const hershey_font_t {font_name} {{
.chars = {{
{chars}
}}
}};
""".format(
font_name=font_name, chars=",\n".join(chars)
)
print(vertex_code)
print(font_code)
return """ {{ \"{font_name}\", &{font_name} }}""".format(font_name=font_name)
# create map of font name to font structure
font_list = []
for input_filename in options.file:
input_file = open(input_filename, mode="r")
data = input_file.read()
input_file.close()
font_list.append(convert_font(data))
map_code = """\
std::map<std::string, const hershey_font_t*> fonts = {{
{font_list}
}};
""".format(
font_list=",\n".join(font_list)
)
print(map_code)