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2025-07-16 15:34:54 +08:00
"""Constants specific the the image sub-package."""
class JPEG_MARKER_CODE:
"""JPEG marker codes."""
TEM = b"\x01"
DHT = b"\xc4"
DAC = b"\xcc"
JPG = b"\xc8"
SOF0 = b"\xc0"
SOF1 = b"\xc1"
SOF2 = b"\xc2"
SOF3 = b"\xc3"
SOF5 = b"\xc5"
SOF6 = b"\xc6"
SOF7 = b"\xc7"
SOF9 = b"\xc9"
SOFA = b"\xca"
SOFB = b"\xcb"
SOFD = b"\xcd"
SOFE = b"\xce"
SOFF = b"\xcf"
RST0 = b"\xd0"
RST1 = b"\xd1"
RST2 = b"\xd2"
RST3 = b"\xd3"
RST4 = b"\xd4"
RST5 = b"\xd5"
RST6 = b"\xd6"
RST7 = b"\xd7"
SOI = b"\xd8"
EOI = b"\xd9"
SOS = b"\xda"
DQT = b"\xdb" # Define Quantization Table(s)
DNL = b"\xdc"
DRI = b"\xdd"
DHP = b"\xde"
EXP = b"\xdf"
APP0 = b"\xe0"
APP1 = b"\xe1"
APP2 = b"\xe2"
APP3 = b"\xe3"
APP4 = b"\xe4"
APP5 = b"\xe5"
APP6 = b"\xe6"
APP7 = b"\xe7"
APP8 = b"\xe8"
APP9 = b"\xe9"
APPA = b"\xea"
APPB = b"\xeb"
APPC = b"\xec"
APPD = b"\xed"
APPE = b"\xee"
APPF = b"\xef"
STANDALONE_MARKERS = (TEM, SOI, EOI, RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7)
SOF_MARKER_CODES = (
SOF0,
SOF1,
SOF2,
SOF3,
SOF5,
SOF6,
SOF7,
SOF9,
SOFA,
SOFB,
SOFD,
SOFE,
SOFF,
)
marker_names = {
b"\x00": "UNKNOWN",
b"\xc0": "SOF0",
b"\xc2": "SOF2",
b"\xc4": "DHT",
b"\xda": "SOS", # start of scan
b"\xd8": "SOI", # start of image
b"\xd9": "EOI", # end of image
b"\xdb": "DQT",
b"\xe0": "APP0",
b"\xe1": "APP1",
b"\xe2": "APP2",
b"\xed": "APP13",
b"\xee": "APP14",
}
@classmethod
def is_standalone(cls, marker_code):
return marker_code in cls.STANDALONE_MARKERS
class MIME_TYPE:
"""Image content types."""
BMP = "image/bmp"
GIF = "image/gif"
JPEG = "image/jpeg"
PNG = "image/png"
TIFF = "image/tiff"
class PNG_CHUNK_TYPE:
"""PNG chunk type names."""
IHDR = "IHDR"
pHYs = "pHYs"
IEND = "IEND"
class TIFF_FLD_TYPE:
"""Tag codes for TIFF Image File Directory (IFD) entries."""
BYTE = 1
ASCII = 2
SHORT = 3
LONG = 4
RATIONAL = 5
field_type_names = {
1: "BYTE",
2: "ASCII char",
3: "SHORT",
4: "LONG",
5: "RATIONAL",
}
TIFF_FLD = TIFF_FLD_TYPE
class TIFF_TAG:
"""Tag codes for TIFF Image File Directory (IFD) entries."""
IMAGE_WIDTH = 0x0100
IMAGE_LENGTH = 0x0101
X_RESOLUTION = 0x011A
Y_RESOLUTION = 0x011B
RESOLUTION_UNIT = 0x0128
tag_names = {
0x00FE: "NewSubfileType",
0x0100: "ImageWidth",
0x0101: "ImageLength",
0x0102: "BitsPerSample",
0x0103: "Compression",
0x0106: "PhotometricInterpretation",
0x010E: "ImageDescription",
0x010F: "Make",
0x0110: "Model",
0x0111: "StripOffsets",
0x0112: "Orientation",
0x0115: "SamplesPerPixel",
0x0117: "StripByteCounts",
0x011A: "XResolution",
0x011B: "YResolution",
0x011C: "PlanarConfiguration",
0x0128: "ResolutionUnit",
0x0131: "Software",
0x0132: "DateTime",
0x0213: "YCbCrPositioning",
0x8769: "ExifTag",
0x8825: "GPS IFD",
0xC4A5: "PrintImageMatching",
}