forked from openkylin/gimp
98 lines
2.2 KiB
Plaintext
98 lines
2.2 KiB
Plaintext
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How GIMP should handle EXIF data
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Bill Skaggs 1/2/05
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This is a summary of how an image editing program is supposed to
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handle each of the EXIF fields, according to the EXIF specs. Note
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that this expresses my understanding based on a quick reading, and
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should not be taken as gospel. For details on the contents of each of
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these fields, consult the formal EXIF specifications, available from
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http://www.exif.org/specifications.html.
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(Note: according to the EXIF specs, an EXIF jpeg file must have a name
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that is ASCII, in 8.3 format, with extension .JPG, but of course we
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are not going to enforce this.)
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Fields that should be used to set up the GIMP image when an EXIF file
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is loaded, either by using them to configure the image (e.g.,
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orientation), or by placing them in parasites that can be accessed by
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non-exif-aware functions.
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Orientation
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XResolution
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YResolution
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ResolutionUnit
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ImageDescription
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Artist
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Copyright
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Colorspace
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ComponentsConfiguration
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UserComment
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SubjectArea
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SubjectLocation
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ImageUniqueID
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PixelXDimension
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PixelYDimension
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Fields that should be modified by GIMP when an EXIF jpeg file is
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saved. A letter "M" indicates fields whose presence is mandatory
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according to the spec.
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Orientation
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XResolution (M)
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YResolution (M)
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ResolutionUnit (M)
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Software
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DateTime
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ImageDescription
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Artist
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Colorspace (M)
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PixelXDimension (M)
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PixelYDimension (M)
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ComponentsConfiguration (M)
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UserComment
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SubsecTime
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SubjectArea
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SubjectLocation
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FileSource
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ImageUniqueID
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thumbnail Compression (M)
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thumbnail XResolution (M)
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thumbnail YResolution (M)
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thumbnail JPEGInterchangeFormat (M)
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thumbnail JPEGInterchangeFormatLength (M)
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Fields that should be used and saved related to color management:
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TransferFunction
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WhitePoint
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PrimaryChromaticity
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YCbCrCoefficients
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ReferenceBlackWhite
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Fields that should be deleted if they exist when saving a file as
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jpeg, because they only apply to uncompressed (TIFF) data. This
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applies both to the main image and to the thumbnail, if there is one.
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ImageWidth
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ImageLength
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BitsPerSample
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Compression
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SamplesPerPixel
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PhotometricInterpretation
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StripOffsets
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PlanarConfiguration
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YCbCrSubSampling
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Any field not mentioned here should be passed through unchanged.
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