Adafruit_CircuitPython_Bitm.../adafruit_bitmap_font/pcf.py
2020-03-15 16:17:54 -04:00

163 lines
5.7 KiB
Python

# pylint: skip-file
# Remove the above when PCF is actually supported.
from .glyph_cache import GlyphCache
import displayio
import struct
_PCF_PROPERTIES = 1 << 0
_PCF_ACCELERATORS = 1 << 1
_PCF_METRICS = 1 << 2
_PCF_BITMAPS = 1 << 3
_PCF_INK_METRICS = 1 << 4
_PCF_BDF_ENCODINGS = 1 << 5
_PCF_SWIDTHS = 1 << 6
_PCF_GLYPH_NAMES = 1 << 7
_PCF_BDF_ACCELERATORS = 1 << 8
_PCF_DEFAULT_FORMAT = 0x00000000
_PCF_INKBOUNDS = 0x00000200
_PCF_ACCEL_W_INKBOUNDS = 0x00000100
_PCF_COMPRESSED_METRICS = 0x00000100
_PCF_GLYPH_PAD_MASK = 3 << 0 # See the bitmap table for explanation */
_PCF_BYTE_MASK = 1 << 2 # If set then Most Sig Byte First */
_PCF_BIT_MASK = 1 << 3 # If set then Most Sig Bit First */
_PCF_SCAN_UNIT_MASK = 3 << 4
# https://fontforge.github.io/en-US/documentation/reference/pcf-format/
class PCF(GlyphCache):
def __init__(self, f):
super().__init__()
self.file = f
self.name = f
f.seek(0)
header, table_count = self.read("<4sI")
self.tables = {}
for _ in range(table_count):
type, format, size, offset = self.read("<IIII")
self.tables[type] = {"format": format, "size": size, "offset": offset}
print(type)
def read(self, format):
s = struct.calcsize(format)
return struct.unpack_from(format, self.file.read(s))
def get_bounding_box(self):
property_table_offset = self.tables[_PCF_PROPERTIES]["offset"]
self.file.seek(property_table_offset)
(format,) = self.read("<I")
if format & _PCF_BYTE_MASK == 0:
raise RuntimeError("Only big endian supported")
(nprops,) = self.read(">I")
self.file.seek(property_table_offset + 8 + 9 * nprops)
pos = self.file.tell()
if pos % 4 > 0:
self.file.read(4 - pos % 4)
(string_size,) = self.read(">I")
strings = self.file.read(string_size)
string_map = {}
i = 0
for s in strings.split(b"\x00"):
string_map[i] = s
i += len(s) + 1
self.file.seek(property_table_offset + 8)
for _ in range(nprops):
name_offset, isStringProp, value = self.read(">IBI")
if isStringProp:
print(string_map[name_offset], string_map[value])
else:
print(string_map[name_offset], value)
return None
def load_glyphs(self, code_points):
metadata = True
character = False
code_point = None
rounded_x = 1
bytes_per_row = 1
desired_character = False
current_info = None
current_y = 0
total_remaining = len(code_points)
x, _, _, _ = self.get_bounding_box()
# create a scratch bytearray to load pixels into
scratch_row = memoryview(bytearray((((x - 1) // 32) + 1) * 4))
self.file.seek(0)
while True:
line = self.file.readline()
if not line:
break
if line.startswith(b"CHARS "):
metadata = False
elif line.startswith(b"SIZE"):
_, self.point_size, self.x_resolution, self.y_resolution = line.split()
elif line.startswith(b"COMMENT"):
pass
elif line.startswith(b"STARTCHAR"):
# print(lineno, line.strip())
# _, character_name = line.split()
character = True
elif line.startswith(b"ENDCHAR"):
character = False
if desired_character:
self._glyphs[code_point] = current_info
if total_remaining == 0:
return
desired_character = False
elif line.startswith(b"BBX"):
if desired_character:
_, x, y, dx, dy = line.split()
x = int(x)
y = int(y)
dx = int(dx)
dy = int(dy)
current_info["bounds"] = (x, y, dx, dy)
current_info["bitmap"] = displayio.Bitmap(x, y, 2)
elif line.startswith(b"BITMAP"):
if desired_character:
rounded_x = x // 8
if x % 8 > 0:
rounded_x += 1
bytes_per_row = rounded_x
if bytes_per_row % 4 > 0:
bytes_per_row += 4 - bytes_per_row % 4
current_y = 0
elif line.startswith(b"ENCODING"):
_, code_point = line.split()
code_point = int(code_point)
if code_point == code_points or code_point in code_points:
total_remaining -= 1
if code_point not in self._glyphs:
desired_character = True
current_info = {"bitmap": None, "bounds": None, "shift": None}
elif line.startswith(b"DWIDTH"):
if desired_character:
_, shift_x, shift_y = line.split()
shift_x = int(shift_x)
shift_y = int(shift_y)
current_info["shift"] = (shift_x, shift_y)
elif line.startswith(b"SWIDTH"):
pass
elif character:
if desired_character:
bits = int(line.strip(), 16)
for i in range(rounded_x):
val = (bits >> ((rounded_x - i - 1) * 8)) & 0xFF
scratch_row[i] = val
current_info["bitmap"]._load_row(
current_y, scratch_row[:bytes_per_row]
)
current_y += 1
elif metadata:
# print(lineno, line.strip())
pass