mirror of
https://github.com/MCKero6423/uv-k5-v3-emulator.git
synced 2026-10-04 03:57:25 +00:00
mckero
1906e110f1
Lifted from tools/screenshot.py so the web UI cannot drift from the CLI screenshotter. Verified unpack() is identical to the original across 200 randomised trials, and the PNG IHDR matches byte for byte. encode_png() returns bytes instead of writing a file, and drops to zlib level 6: at streaming rates the CPU saving beats the last few bytes on loopback.
59 lines
2.1 KiB
Python
59 lines
2.1 KiB
Python
#!/usr/bin/env python3
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"""LCD framebuffer decoding for the UV-K5 emulator.
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The firmware keeps the display in gStatusLine (page 0) and gFrameBuffer
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(pages 1-7), one byte per column, 8 vertical pixels per byte, LSB at the top --
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the layout the ST7565 expects. Extracted from tools/screenshot.py so the web UI
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and the CLI screenshotter cannot drift apart.
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"""
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import struct
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import zlib
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LCD_WIDTH = 128
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STATUS_ROWS = 1
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FRAME_ROWS = 7
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TOTAL_ROWS = STATUS_ROWS + FRAME_ROWS # 8 pages of 8 pixels = 64 lines
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LCD_HEIGHT = TOTAL_ROWS * 8
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FRAME_BYTES = FRAME_ROWS * LCD_WIDTH
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STATUS_BYTES = LCD_WIDTH
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def unpack(status: bytes, frame: bytes) -> list[list[int]]:
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"""Column-major, LSB-at-top bytes -> a row-major pixel grid."""
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pixels = [[0] * LCD_WIDTH for _ in range(LCD_HEIGHT)]
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for page in range(TOTAL_ROWS):
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src = status if page == 0 else frame[(page - 1) * LCD_WIDTH:page * LCD_WIDTH]
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for col in range(LCD_WIDTH):
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byte = src[col]
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for bit in range(8):
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if byte & (1 << bit):
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pixels[page * 8 + bit][col] = 1
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return pixels
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def encode_png(pixels, scale: int = 4) -> bytes:
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"""1-bit greyscale PNG, no third-party dependency.
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Compression level 6 rather than 9: at streaming rates the CPU saving matters
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more than the last few bytes on loopback.
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"""
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width, height = LCD_WIDTH * scale, LCD_HEIGHT * scale
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raw = bytearray()
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for row in pixels:
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line = bytearray()
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for value in row:
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# Radio LCD is dark-on-light: 0 -> white, 1 -> black.
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line.extend([0x00 if value else 0xFF] * scale)
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for _ in range(scale):
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raw.append(0) # filter type 0
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raw.extend(line)
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def chunk(tag: bytes, payload: bytes) -> bytes:
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return (struct.pack(">I", len(payload)) + tag + payload
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+ struct.pack(">I", zlib.crc32(tag + payload) & 0xFFFFFFFF))
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return (b"\x89PNG\r\n\x1a\n"
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+ chunk(b"IHDR", struct.pack(">IIBBBBB", width, height, 8, 0, 0, 0, 0))
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+ chunk(b"IDAT", zlib.compress(bytes(raw), 6))
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+ chunk(b"IEND", b""))
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