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| 1 | +# SPDX-FileCopyrightText: 2025 Anne Barela for Adafruit Industries |
| 2 | +# |
| 3 | +# SPDX-License-Identifier: MIT |
| 4 | +# |
| 5 | +# Take a BDF or PCF font file and display it on a CircuitPython |
| 6 | +# HDMI/DVI display in 320x200 resolution. "." is used for unknown characters |
| 7 | + |
| 8 | +import gc |
| 9 | +import displayio |
| 10 | +import supervisor |
| 11 | +from adafruit_bitmap_font import bitmap_font |
| 12 | +from adafruit_display_text import label |
| 13 | +from adafruit_fruitjam.peripherals import request_display_config |
| 14 | + |
| 15 | +# Use the easy library call to set the resolution |
| 16 | +request_display_config(320, 240) |
| 17 | + |
| 18 | +# Initialize display |
| 19 | +display = supervisor.runtime.display |
| 20 | +main_group = displayio.Group() |
| 21 | +display.root_group = main_group |
| 22 | + |
| 23 | +# Use Labels to display characters that exist in font |
| 24 | +font_file = "fonts/cp437-8x12a.pcf" |
| 25 | +font = bitmap_font.load_font(font_file) # Use font = terminalio.FONT for built-in |
| 26 | +char_width = 8 # font character width |
| 27 | +char_height = 12 # font character height |
| 28 | +chars_per_line = 32 # Fixed at 32 characters per line |
| 29 | +line_number_width = 35 # Space for line numbers like "000: " |
| 30 | + |
| 31 | +displayed_count = 0 |
| 32 | +skipped_count = 0 |
| 33 | + |
| 34 | +current_x = line_number_width # Start after line number space |
| 35 | +current_y = char_height |
| 36 | +current_line_start = 0 |
| 37 | + |
| 38 | +# Add first line number |
| 39 | +line_label = label.Label( |
| 40 | + font, |
| 41 | + text=f"{current_line_start:03d}: ", |
| 42 | + color=0xFFFFFF, |
| 43 | + x=0, |
| 44 | + y=current_y |
| 45 | +) |
| 46 | +main_group.append(line_label) |
| 47 | + |
| 48 | +# Try all characters from 0-255 and display ones that exist |
| 49 | +for char_code in range(256): |
| 50 | + try: |
| 51 | + # Check if we need to wrap to next line |
| 52 | + if (char_code > 0) and (char_code % chars_per_line == 0): |
| 53 | + current_x = line_number_width # Reset to after line number |
| 54 | + current_y += char_height + 2 # Add some line spacing |
| 55 | + current_line_start = char_code |
| 56 | + |
| 57 | + # Stop if we run out of vertical space |
| 58 | + if current_y + char_height > display.height: |
| 59 | + print(f"Display full, stopped at {char_code}") |
| 60 | + break |
| 61 | + |
| 62 | + # Add line number for this new line |
| 63 | + line_label = label.Label( |
| 64 | + font, |
| 65 | + text=f"{current_line_start:03d}: ", |
| 66 | + color=0xFFFFFF, |
| 67 | + x=0, |
| 68 | + y=current_y |
| 69 | + ) |
| 70 | + main_group.append(line_label) |
| 71 | + |
| 72 | + # Check if glyph exists |
| 73 | + glyph = font.get_glyph(char_code) |
| 74 | + |
| 75 | + if glyph is None: |
| 76 | + # No glyph available - display a period instead |
| 77 | + display_char = "." |
| 78 | + skipped_count += 1 |
| 79 | + else: |
| 80 | + # Glyph exists - display the actual character |
| 81 | + display_char = chr(char_code) |
| 82 | + |
| 83 | + # Create label for this character (or replacement) |
| 84 | + char_label = label.Label( |
| 85 | + font, |
| 86 | + text=display_char, |
| 87 | + color=0xFFFFFF, |
| 88 | + x=current_x, |
| 89 | + y=current_y |
| 90 | + ) |
| 91 | + |
| 92 | + main_group.append(char_label) |
| 93 | + current_x += char_width |
| 94 | + displayed_count += 1 |
| 95 | + |
| 96 | + except (MemoryError, ValueError) as e: |
| 97 | + print(f"Memory limit reached at char {char_code}") |
| 98 | + break |
| 99 | + |
| 100 | + # Garbage collection every 16 characters |
| 101 | + if char_code % 16 == 0: |
| 102 | + gc.collect() |
| 103 | + |
| 104 | +print(f"Found {displayed_count - skipped_count} chars with glyphs") |
| 105 | +print(f"{skipped_count} missing chars -> periods") |
| 106 | +print(f"Free memory: {gc.mem_free()} bytes") |
| 107 | + |
| 108 | +# Keep display active |
| 109 | +while True: |
| 110 | + pass |
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