Marlin/buildroot/share/scripts/rle_compress_bitmap.py
2024-10-25 21:01:00 +02:00

201 lines
6.6 KiB
Python
Executable File

#!/usr/bin/env python3
#
# Bitwise RLE compress a Marlin mono DOGM bitmap.
# Input: An existing Marlin Marlin mono DOGM bitmap .cpp or .h file.
# Output: A new file with the original and compressed data.
#
# Usage: rle_compress_bitmap.py INPUT_FILE OUTPUT_FILE
#
import sys,struct
import re
def addCompressedData(input_file, output_file):
ofile = open(output_file, 'wt')
datatype = "uint8_t"
bytewidth = 16
raw_data = []
arrname = ''
c_data_section = False ; c_skip_data = False ; c_footer = False
while True:
line = input_file.readline()
if not line: break
if not c_footer:
if not c_skip_data: ofile.write(line)
mat = re.match(r'.+CUSTOM_BOOTSCREEN_BMPWIDTH\s+(\d+)', line)
if mat: bytewidth = (int(mat[1]) + 7) // 8
if "};" in line:
c_skip_data = False
c_data_section = False
c_footer = True
if c_data_section:
cleaned = re.sub(r"\s|,|\n", "", line)
mat = re.match(r'(0b|B)[01]{8}', cleaned)
if mat:
as_list = cleaned.split(mat[1])
as_list.pop(0)
raw_data += [int(x, 2) for x in as_list]
else:
as_list = cleaned.split("0x")
as_list.pop(0)
raw_data += [int(x, 16) for x in as_list]
mat = re.match(r'const (uint\d+_t|unsigned char)', line)
if mat:
# e.g.: const unsigned char custom_start_bmp[] PROGMEM = {
datatype = mat[0]
if "_rle" in line:
c_skip_data = True
else:
c_data_section = True
arrname = line.split('[')[0].split(' ')[-1]
print("Found data array", arrname)
input_file.close()
#print("\nRaw Bitmap Data", raw_data)
#
# Bitwise RLE (run length) encoding
# Convert data from raw mono bitmap to a bitwise run-length-encoded format.
# - The first nybble is the starting bit state. Changing this nybble inverts the bitmap.
# - The following bytes provide the runs for alternating on/off bits.
# - A value of 0-14 encodes a run of 1-15.
# - A value of 16 indicates a run of 16-270 calculated using the next two bytes.
#
def bitwise_rle_encode(data):
def get_bit(data, n): return 1 if (data[n // 8] & (0x80 >> (n & 7))) else 0
def try_encode(data, isext):
bitslen = len(data) * 8
bitstate = get_bit(data, 0)
rledata = [ bitstate ]
bigrun = 256 if isext else 272
medrun = False
i = 0
runlen = -1
while i <= bitslen:
if i < bitslen: b = get_bit(data, i)
runlen += 1
if bitstate != b or i == bitslen:
if runlen >= bigrun:
isext = True
if medrun: return [], isext
rem = runlen & 0xFF
rledata += [ 15, 15, rem // 16, rem % 16 ]
elif runlen >= 16:
rledata += [ 15, runlen // 16 - 1, runlen % 16 ]
if runlen >= 256: medrun = True
else:
rledata += [ runlen - 1 ]
bitstate ^= 1
runlen = 0
i += 1
#print("\nrledata", rledata)
encoded = []
ri = 0
rlen = len(rledata)
while ri < rlen:
v = rledata[ri] << 4
if (ri < rlen - 1): v |= rledata[ri + 1]
encoded += [ v ]
ri += 2
#print("\nencoded", encoded)
return encoded, isext
# Try to encode with the original isext flag
warn = "This may take a while" if len(data) > 300000 else ""
print("Compressing image data...", warn)
isext = False
encoded, isext = try_encode(data, isext)
if len(encoded) == 0:
encoded, isext = try_encode(data, True)
return encoded, isext
def bitwise_rle_decode(isext, rledata, invert=0):
expanded = []
for n in rledata: expanded += [ n >> 4, n & 0xF ]
decoded = []
bitstate = 0 ; workbyte = 0 ; outindex = 0
i = 0
while i < len(expanded):
c = expanded[i]
i += 1
if i == 1: bitstate = c ; continue
if c == 15:
d = expanded[i] ; e = expanded[i + 1]
if isext and d == 15:
c = 256 + 16 * e + expanded[i + 2] - 1
i += 1
else:
c = 16 * d + e + 15
i += 2
for _ in range(c, -1, -1):
bitval = 0x80 >> (outindex & 7)
if bitstate: workbyte |= bitval
if bitval == 1:
decoded += [ workbyte ]
workbyte = 0
outindex += 1
bitstate ^= 1
print("\nDecoded RLE data:")
pretty = [ '{0:08b}'.format(v) for v in decoded ]
rows = [pretty[i:i+bytewidth] for i in range(0, len(pretty), bytewidth)]
for row in rows: print(f"{''.join(row)}")
return decoded
def rle_emit(ofile, arrname, rledata, rawsize, isext):
outstr = ''
rows = [ rledata[i:i+16] for i in range(0, len(rledata), 16) ]
for i in range(0, len(rows)):
rows[i] = [ '0x{0:02X}'.format(v) for v in rows[i] ]
outstr += f" {', '.join(rows[i])},\n"
outstr = outstr[:-2]
size = len(rledata)
defname = 'COMPACT_CUSTOM_BOOTSCREEN_EXT' if isext else 'COMPACT_CUSTOM_BOOTSCREEN'
ofile.write(f"\n// Saves {rawsize - size} bytes\n#define {defname}\n{datatype} {arrname}_rle[{size}] PROGMEM = {{\n{outstr}\n}};\n")
# Encode the data, write it out, close the file
rledata, isext = bitwise_rle_encode(raw_data)
rle_emit(ofile, arrname, rledata, len(raw_data), isext)
ofile.close()
# Validate that code properly compressed (and decompressed) the data
checkdata = bitwise_rle_decode(isext, rledata)
for i in range(0, len(checkdata)):
if raw_data[i] != checkdata[i]:
print(f'Data mismatch at byte offset {i} (should be {raw_data[i]} but got {checkdata[i]})')
break
if len(sys.argv) <= 2:
print('Usage: rle_compress_bitmap.py INPUT_FILE OUTPUT_FILE')
exit(1)
output_cpp = sys.argv[2]
inname = sys.argv[1].replace('//', '/')
try:
input_cpp = open(inname)
print("Processing", inname, "...")
addCompressedData(input_cpp, output_cpp)
except OSError:
print("Can't find input file", inname)