#!/usr/bin/env python3
"""B9A read-only: render the 128x128 RGB565 (little-endian u16) default splash embedded in stock LK
(imageBuffer @0x8f64b004, used by display_image_on_screen() when the splash partition has no 'SPLASH!!' header)
to a 2x-scaled PNG. usage: render-lk-logo.py lk.bin out.png"""
import struct, sys, zlib
d = open(sys.argv[1], 'rb').read(); o = 0x8f64b004 - 0x8f600000; W = H = 128
rows = []
for y in range(H):
    r = bytearray()
    for x in range(W):
        v = struct.unpack_from('<H', d, o + (y * W + x) * 2)[0]
        r += bytes(((v >> 11 & 31) * 255 // 31, (v >> 5 & 63) * 255 // 63, (v & 31) * 255 // 31)) * 2
    rows += [bytes(r)] * 2
def ch(t, b): return struct.pack('>I', len(b)) + t + b + struct.pack('>I', zlib.crc32(t + b) & 0xffffffff)
open(sys.argv[2], 'wb').write(b'\x89PNG\r\n\x1a\n' + ch(b'IHDR', struct.pack('>IIBBBBB', W * 2, H * 2, 8, 2, 0, 0, 0))
                              + ch(b'IDAT', zlib.compress(b''.join(b'\0' + r for r in rows))) + ch(b'IEND', b''))