rick/LEDMatrix
1
0
Fork 0
mirror of https://github.com/ChuckBuilds/LEDMatrix.git synced 2026-10-04 06:15:09 +00:00
Code Issues Packages Projects Releases Wiki Activity

refactor(fonts): one BDF loader and one BDF rasterizer (#627)

Browse Source 
* refactor(fonts): one BDF loader and one BDF rasterizer

BDF faces were loaded three ways (FontManager._load_bdf_font,
element_style._load_bdf, DisplayManager._load_fonts) and drawn by two
copies of the same per-pixel loop (DisplayManager._draw_bdf_text and the
plugin test harness's "replicated" copy), which golden images and
check_plugin/dev_server previews rely on matching the panel.

src/common/bdf_font.py now owns both:
- load_bdf_face(path, size) -> (face, realised_px): native-strike fallback
  for sizes the file lacks, one bounded LRU cache keyed on path, size and
  mtime. FontManager, element_style and DisplayManager delegate to it;
  read_bdf_native_size moves here (the old names delegate).
- draw_bdf_text(draw, text, x, y, face, color, clip): builds each glyph as
  a 1-bit mask and fills it with ImageDraw.bitmap instead of a draw.point
  per pixel. A blending Draw (RGB image, "RGBA" mode) keeps the point path
  so translucent colours still blend.

Pixel-identical: 220,032 renders (every bundled BDF at native and
off-strike sizes, 14 strings, 4 colours, clipped on every edge, through
each old loader x rasterizer) match origin/main byte for byte.
test/test_bdf_font.py keeps a lightweight version against a frozen copy of
the old loop. DisplayManager._draw_bdf_text goes from 1.4-23 ms to about
0.1 ms per string (the old loop re-read FreeType's buffer as a Python list
for every pixel).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(testing): harness calendar_font is sized like the panel's

VisualTestDisplayManager built its 5x7 calendar_font / bdf_5x7_font as a
bare freetype.Face. With no size set its ascender reads 0, so BDF text
drawn with it landed 6px above where DisplayManager draws it -- entirely
off the canvas at y=0 -- and get_font_height() returned 0. Golden images
and check_plugin / dev_server previews showed text the panel does not.

Load it through load_bdf_face at the panel's 7px, so it is the very face
DisplayManager uses. Across the differential run this changes only the
cases drawn with the harness's own calendar_font (968 of 220,032), which
now match the panel's output.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(fonts): one BDF face per thread

The shared face cache now hands every loader (FontManager, element_style,
DisplayManager, the harness) the same freetype.Face. FreeType does not allow
two threads to use one face at once, since load_char rewrites its glyph
slot, so key the cache by thread as well.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Chuck
2026-09-24 15:51:53 -04:00
committed by GitHub
co-authored by Claude Opus 5.5
parent abedc46104
commit afe9001aed
8 changed files with 619 additions and 175 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/display_manager.py
+16 -48
View File
@@ -34,6 +34,7 @@ else:
from contextlib import contextmanager
from pathlib import Path
from PIL import Image, ImageDraw, ImageFont
from src.common.bdf_font import draw_bdf_text, load_bdf_face
from src.common.font_layout import crisp_size, load_truetype, resolve_asset_path
from src.display_geometry import (
DEFAULT_CHAIN_LENGTH, DEFAULT_COLS, DEFAULT_PARALLEL, DEFAULT_ROWS,
@@ -884,43 +885,16 @@ class DisplayManager:
logger.error(f"Error clearing display: {e}")
def _draw_bdf_text(self, text, x, y, color=(255, 255, 255), font=None):
"""Draw text using BDF font with proper bitmap handling."""
"""Draw text in a BDF ``freetype.Face`` with (x, y) as its top-left.
Delegates to :func:`src.common.bdf_font.draw_bdf_text`, which the
plugin test harness uses too, so previews and golden images show the
pixels the panel does. Clipped to the logical display size.
"""
try:
# Use the passed font or fall back to calendar_font
face = font if font else self.calendar_font
# Compute baseline from font ascender so caller can pass top-left y
try:
ascender_px = face.size.ascender >> 6
except Exception:
ascender_px = 0
baseline_y = y + ascender_px
for char in text:
face.load_char(char)
bitmap = face.glyph.bitmap
# Get glyph metrics
glyph_left = face.glyph.bitmap_left
glyph_top = face.glyph.bitmap_top
# Draw the character
for i in range(bitmap.rows):
for j in range(bitmap.width):
byte_index = i * bitmap.pitch + (j // 8)
if byte_index < len(bitmap.buffer):
byte = bitmap.buffer[byte_index]
if byte & (1 << (7 - (j % 8))):
# Calculate actual pixel position
pixel_x = x + glyph_left + j
pixel_y = baseline_y - glyph_top + i
# Only draw if within bounds
if (0 <= pixel_x < self.width and 0 <= pixel_y < self.height):
self.draw.point((pixel_x, pixel_y), fill=color)
# Move to next character
x += face.glyph.advance.x >> 6
draw_bdf_text(self.draw, text, x, y, face, color,
clip=(self.width, self.height))
except Exception as e:
logger.error(f"Error drawing BDF text: {e}", exc_info=True)
@@ -969,19 +943,13 @@ class DisplayManager:
if not os.path.exists(self.calendar_font_path):
raise FileNotFoundError(f"Font file not found at {self.calendar_font_path}")
# Load with freetype for proper BDF handling
face = freetype.Face(self.calendar_font_path)
# A freshly constructed Face has no active size, so
# face.size.height is 0 until set_char_size is called -- and
# get_font_height() reads exactly that. Without this, every
# caller measuring the 5x7 face got 0 and stacked rows on top
# of one another; the "Calendar font size: 0 pixels" line
# below has been printing the symptom on every start-up.
# font_manager._load_bdf_font already does this; the two paths
# disagreed about whether a Face was usable for measurement.
# 5x7.bdf is a fixed strike, so FreeType renders 7px whatever
# is asked for -- this sets the metrics, not the raster.
face.set_char_size(_CALENDAR_FONT_PX * 64, _CALENDAR_FONT_PX * 64, 72, 72)
# load_bdf_face sets the size: a Face built without
# set_char_size reports face.size.height 0, and every caller
# measuring the 5x7 face with get_font_height() got 0 and
# stacked rows on top of one another. 5x7.bdf is a fixed
# strike, so FreeType renders 7px whatever is asked for --
# the size sets the metrics, not the raster.
face, _ = load_bdf_face(self.calendar_font_path, _CALENDAR_FONT_PX)
logger.info(f"5x7 calendar font loaded successfully from {self.calendar_font_path}")
logger.info(f"Calendar font size: {face.size.height >> 6} pixels")