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util/font: Add support for dynamic canvas dimensions

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Update generate_font.py to support user-defined canvas width and height
via command-line arguments. This replaces the hardcoded 16x24 limits.

Key changes:
- Use argparse for --width and --height parameters.
- Ensure glyphs are left-aligned to the MSB (bit 15 or 31) for
  scalability.

TEST=Able to create font table upto 32 pixels wide.

```
python generate_font.py <path_to_ttf> --width 24 --height 32 > font_table.c
```

Change-Id: Ifd02a979abf41a2c2b088ae58bb931f9f6421491
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/91165
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Subrata Banik 2026-02-11 20:21:21 +05:30
commit 96b29e37db
1 changed files with 64 additions and 36 deletions
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104
util/font/generate_font.py
View file

@ -9,31 +9,40 @@ The output is a C source file containing:
3. A character width table for proportional spacing.
Usage:
python generate_font.py <path_to_ttf> > font_table.c
python generate_font.py <path_to_ttf> --width 24 --height 32 > font_table.c
"""
import argparse
from PIL import Image, ImageFont, ImageDraw
import sys
import os
# FONT DIMENSIONS
FONT_SIZE = 19
CANVAS_WIDTH = 16
CANVAS_HEIGHT = 24
Y_OFFSET = -2
# PRINTABLE ASCII RANGE
START_CHAR = 32
END_CHAR = 126
NUM_CHARS = END_CHAR - START_CHAR + 1
def generate_c_table(font_path):
def generate_c_table(font_path, canvas_width, canvas_height):
if not os.path.exists(font_path):
print(f"Error: Font file '{font_path}' not found.", file=sys.stderr)
sys.exit(1)
# Validation: Width must not exceed 32 bits for uint32_t storage
if canvas_width > 32:
print(f"Error: Requested width ({canvas_width}) exceeds 32-bit capacity. "
"The current renderer supports up to 32 pixels wide.", file=sys.stderr)
sys.exit(1)
# Validation: Basic sanity check for positive dimensions
if canvas_width <= 0 or canvas_height <= 0:
print("Error: Width and Height must be positive integers.", file=sys.stderr)
sys.exit(1)
# Use canvas_width as font size to maintain original calculation style
font_size = canvas_width
y_offset = 0
try:
font = ImageFont.truetype(font_path, FONT_SIZE)
font = ImageFont.truetype(font_path, font_size)
except OSError:
print(f"Error: Could not open font file '{font_path}'.", file=sys.stderr)
sys.exit(1)
@ -43,63 +52,79 @@ def generate_c_table(font_path):
print("/*")
print(" * THIS FILE WAS AUTOMATICALLY GENERATED. DO NOT EDIT.")
print(f" * Source: {os.path.basename(font_path)}")
print(f" * Command: python util/font/{os.path.basename(__file__)} {font_path}")
print(f" * Command: python {os.path.basename(__file__)} {font_path} --width {canvas_width} --height {canvas_height}")
print(" */\n")
print("#include <stdint.h>\n")
# 1. Output the Macros for C code usage
print(f"#define FONT_WIDTH {CANVAS_WIDTH}")
print(f"#define FONT_HEIGHT {CANVAS_HEIGHT}")
print(f"#define FONT_WIDTH {canvas_width}")
print(f"#define FONT_HEIGHT {canvas_height}")
print(f"#define FONT_START_CHAR {START_CHAR}")
print(f"#define FONT_END_CHAR {END_CHAR}")
print(f"#define FONT_NUM_CHARS (FONT_END_CHAR - FONT_START_CHAR + 1)\n")
widths = []
# 2. Generate packed font table with block formatting
print(f"const uint16_t font_table[FONT_NUM_CHARS][FONT_HEIGHT] = {{")
# Choose data type based on width
data_type = "uint32_t"
hex_format = "08x" if canvas_width > 16 else "04x"
bit_depth = 32 if canvas_width > 16 else 16
# 2. Generate packed font table
print(f"const {data_type} font_table[FONT_NUM_CHARS][FONT_HEIGHT] = {{")
for char_code in range(START_CHAR, END_CHAR + 1):
char = chr(char_code)
image = Image.new("1", (CANVAS_WIDTH, CANVAS_HEIGHT), 0)
image = Image.new("1", (canvas_width, canvas_height), 0)
draw = ImageDraw.Draw(image)
draw.text((0, Y_OFFSET), char, font=font, fill=1)
draw.text((0, y_offset), char, font=font, fill=1)
pixels = list(image.getdata())
rows = []
global_mask = 0
for y in range(CANVAS_HEIGHT):
for y in range(canvas_height):
row_val = 0
base = y * CANVAS_WIDTH
for x in range(CANVAS_WIDTH):
base = y * canvas_width
for x in range(canvas_width):
if pixels[base + x]:
row_val |= (1 << ((CANVAS_WIDTH - 1) - x))
# Map pixels to bits: Leftmost pixel is highest bit
row_val |= (1 << ((canvas_width - 1) - x))
rows.append(row_val)
global_mask |= row_val
# Dead space removal / Normalization
left_shift = 0
actual_width = 0
if global_mask > 0:
temp_mask = global_mask
while not (temp_mask & 0x8000):
temp_mask <<= 1
left_shift += 1
rightmost_bit = 0
for i in range(CANVAS_WIDTH):
if (global_mask >> i) & 1:
rightmost_bit = i
if global_mask > 0:
# Find the leftmost pixel column
leftmost_col = 0
for i in range(canvas_width):
if (global_mask >> (canvas_width - 1 - i)) & 1:
leftmost_col = i
break
actual_width = ((CANVAS_WIDTH - 1) - left_shift) - rightmost_bit + 1
# Find the rightmost pixel column
rightmost_col = 0
for i in range(canvas_width):
if (global_mask >> i) & 1:
rightmost_col = (canvas_width - 1) - i
break
# Width is the horizontal span of active pixels
actual_width = rightmost_col - leftmost_col + 1
# left_shift ensures character is left-aligned to MSB of the data type
left_shift = (bit_depth - canvas_width) + leftmost_col
else:
actual_width = 6 # Default space width
actual_width = canvas_width // 3 # Default width for space
widths.append(actual_width)
# Format the pre-shifted hex rows into blocks of 8
hex_values = [f"0x{(row << left_shift) & 0xFFFF:04x}" for row in rows]
# Pre-shift values to be MSB-aligned and mask based on bit depth
mask_val = 0xFFFFFFFF if bit_depth == 32 else 0xFFFF
hex_values = [f"0x{(row << left_shift) & mask_val:{hex_format}}" for row in rows]
char_repr = f"'{char}'" if char not in ["'", "\\"] else f"'\\{char}'"
print(f"\t[0x{char_code:02x} - FONT_START_CHAR] = {{")
@ -118,7 +143,10 @@ def generate_c_table(font_path):
print("};")
if __name__ == "__main__":
if len(sys.argv) < 2:
print(f"Usage: python3 {sys.argv[0]} <path_to_ttf_file>")
sys.exit(1)
generate_c_table(sys.argv[1])
parser = argparse.ArgumentParser(description="Generate bitmapped font table.")
parser.add_argument("font_path", help="Path to TTF/OTF font file")
parser.add_argument("--width", type=int, default=24, help="Canvas width (default: 24)")
parser.add_argument("--height", type=int, default=32, help="Canvas height (default: 32)")
args = parser.parse_args()
generate_c_table(args.font_path, args.width, args.height)