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Update lspng.py script to use functions implemented into YOGA

This commit is contained in:
Fabien LOISON 2021-07-02 16:09:42 +02:00
parent 2d6421e1c7
commit a615e7c9d4
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GPG Key ID: FF90CA148348048E
1 changed files with 12 additions and 69 deletions
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81
scripts/lspng.py
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@ -4,72 +4,13 @@ import sys
import struct
import zlib
def big_endian_uint32_bytes_to_python_int(bytes_):
return struct.unpack(">L", bytes_)[0]
from yoga.image.encoders import png
def big_endian_uint16_bytes_to_python_int(bytes_):
return struct.unpack(">H", bytes_)[0]
def get_png_structure(data):
PNG_MAGIC = b"\x89PNG\r\n\x1A\n"
if not data.startswith(PNG_MAGIC):
raise ValueError("Unvalid PNG: Not a PNG file")
result = {
"size": len(data),
"chunks": [],
}
offset = len(PNG_MAGIC)
while offset < result["size"]:
chunk = {
"type": data[offset + 4 : offset + 8].decode(),
"data_offset": offset + 8,
"size": big_endian_uint32_bytes_to_python_int(
data[offset : offset + 4]
),
"crc": None,
}
chunk["crc"] = big_endian_uint32_bytes_to_python_int(
data[
chunk["data_offset"]
+ chunk["size"] : chunk["data_offset"]
+ chunk["size"]
+ 4
]
)
result["chunks"].append(chunk)
offset += 12 + chunk["size"]
return result
def get_IHDR_info(data):
PNG_COLOR_TYPE = {
0: "Grayscale",
2: "Truecolour",
3: "Indexed-colour",
4: "Grayscale with alpha",
6: "Truecolour with alpha",
}
return {
"width": big_endian_uint32_bytes_to_python_int(data[0:4]),
"height": big_endian_uint32_bytes_to_python_int(data[4:8]),
"bit_depth": data[8],
"colour_type": data[9],
"colour_type_str": PNG_COLOR_TYPE[data[9]],
"compression_method": data[10],
"filter_method": data[11],
"interlace_method": data[12],
}
def get_sBIT_info(data, colour_type):
if colour_type == 0: # Grayscale
return {
@ -101,8 +42,12 @@ def get_pHYs_info(data):
1: "metre",
}
return {
"pixels_per_unit_x": big_endian_uint32_bytes_to_python_int(data[0:4]),
"pixels_per_unit_y": big_endian_uint32_bytes_to_python_int(data[4:8]),
"pixels_per_unit_x": png.big_endian_uint32_bytes_to_python_int(
data[0:4]
),
"pixels_per_unit_y": png.big_endian_uint32_bytes_to_python_int(
data[4:8]
),
"unit_specifier": data[8],
"unit_specifier_str": PNG_UNITS[data[8]],
}
@ -129,9 +74,7 @@ def get_tIME_info(data):
def get_bKGD_info(data, colour_type):
if colour_type in [0, 4]: # Grayscale, Grayscale with alpha
return {
"grayscale": big_endian_uint32_bytes_to_python_int(b"\0\0" + data)
}
return {"grayscale": big_endian_uint16_bytes_to_python_int(data)}
elif colour_type in [2, 6]: # Truecolour, Truecolour with alpha
return {
"red": big_endian_uint16_bytes_to_python_int(data[0:2]),
@ -156,12 +99,12 @@ def calculate_crc32(image_data, chunk_info):
def print_png_info(input_path):
image = open(input_path, "rb").read()
png = get_png_structure(image)
png_structure = png.get_png_structure(image)
print("+-- %s" % input_path)
print(" +-- PNG [size: %i]" % png["size"])
print(" +-- PNG [size: %i]" % png_structure["size"])
for chunk in png["chunks"]:
for chunk in png_structure["chunks"]:
print(
" +-- %s [offset: %i, size: %i, crc: %08X (%s)]"
% (
@ -175,7 +118,7 @@ def print_png_info(input_path):
)
)
if chunk["type"] == "IHDR":
ihdr_info = get_IHDR_info(
ihdr_info = png.get_IHDR_info(
image[
chunk["data_offset"] : chunk["data_offset"] + chunk["size"]
]