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trezor-firmware/core/tools/codegen/gen_font.py
2019-04-15 19:14:40 +02:00

116 lines
4.6 KiB
Python
Executable File

#!/usr/bin/env python3
# script used to generate /embed/extmod/modtrezorui/font_*_*.c
import freetype
MIN_GLYPH = ord(" ")
MAX_GLYPH = ord("~")
FONT_BPP = 4
# metrics explanation: https://www.freetype.org/freetype2/docs/glyphs/metrics.png
def process_face(name, style, size):
print("Processing ... %s %s %s" % (name, style, size))
face = freetype.Face("/usr/share/fonts/truetype/%s-%s.ttf" % (name, style))
face.set_pixel_sizes(0, size)
fontname = "%s_%s_%d" % (name.lower(), style.lower(), size)
with open("font_%s.h" % fontname, "wt") as f:
f.write("#include <stdint.h>\n\n")
f.write(
"extern const uint8_t* const Font_%s_%s_%d[%d + 1 - %d];\n"
% (name, style, size, MAX_GLYPH, MIN_GLYPH)
)
with open("font_%s.c" % fontname, "wt") as f:
f.write('#include "font_%s.h"\n\n' % fontname)
f.write("// first two bytes are width and height of the glyph\n")
f.write("// third, fourth and fifth bytes are advance\n")
f.write("// bearingX and bearingY of the horizontal metrics of the glyph\n")
f.write("// rest is packed 4-bit glyph data\n\n")
f.write("// clang-format off\n\n")
for i in range(MIN_GLYPH, MAX_GLYPH + 1):
c = chr(i)
face.load_char(c, freetype.FT_LOAD_RENDER | freetype.FT_LOAD_TARGET_NORMAL)
bitmap = face.glyph.bitmap
metrics = face.glyph.metrics
assert metrics.width // 64 == bitmap.width
assert metrics.height // 64 == bitmap.rows
assert metrics.width % 64 == 0
assert metrics.height % 64 == 0
assert metrics.horiAdvance % 64 == 0
assert metrics.horiBearingX % 64 == 0
assert metrics.horiBearingY % 64 == 0
assert bitmap.width == bitmap.pitch
assert len(bitmap.buffer) == bitmap.pitch * bitmap.rows
width = bitmap.width
rows = bitmap.rows
advance = metrics.horiAdvance // 64
bearingX = metrics.horiBearingX // 64
# the following code is here just for some letters (listed below)
# not using negative bearingX makes life so much easier; add it to advance instead
if c in "jy}),/" and bearingX < 0:
advance += -bearingX
bearingX = 0
bearingY = metrics.horiBearingY // 64
assert advance >= 0 and advance <= 255
assert bearingX >= 0 and bearingX <= 255
assert bearingY >= 0 and bearingY <= 255
print(
'Loaded glyph "%c" ... %d x %d @ %d grays (%d bytes, metrics: %d, %d, %d)'
% (
c,
bitmap.width,
bitmap.rows,
bitmap.num_grays,
len(bitmap.buffer),
advance,
bearingX,
bearingY,
)
)
f.write(
"/* %c */ static const uint8_t Font_%s_%s_%d_glyph_%d[] = { %d, %d, %d, %d, %d"
% (c, name, style, size, i, width, rows, advance, bearingX, bearingY)
)
buf = list(bitmap.buffer)
if len(buf) > 0:
if FONT_BPP == 2:
for _ in range(4 - len(buf) % 4):
buf.append(0)
buf = [
(
(a & 0xC0)
| ((b & 0xC0) >> 2)
| ((c & 0xC0) >> 4)
| ((d & 0xC0) >> 6)
)
for a, b, c, d in [
buf[i : i + 4] for i in range(0, len(buf), 4)
]
]
elif FONT_BPP == 4:
if len(buf) % 2 > 0:
buf.append(0)
buf = [
((a & 0xF0) | (b >> 4))
for a, b in [buf[i : i + 2] for i in range(0, len(buf), 2)]
]
f.write(", " + ", ".join(["%d" % x for x in buf]))
f.write(" };\n")
f.write(
"\nconst uint8_t * const Font_%s_%s_%d[%d + 1 - %d] = {\n"
% (name, style, size, MAX_GLYPH, MIN_GLYPH)
)
for i in range(MIN_GLYPH, MAX_GLYPH + 1):
f.write(" Font_%s_%s_%d_glyph_%d,\n" % (name, style, size, i))
f.write("};\n")
process_face("Roboto", "Regular", 20)
process_face("Roboto", "Bold", 20)
process_face("RobotoMono", "Regular", 20)
process_face("RobotoMono", "Bold", 20)