From 5c1676dfe6d2f3c837a5e074117b45613fd29a72 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:30:19 +0200 Subject: Adding upstream version 2.10.34. Signed-off-by: Daniel Baumann --- devel-docs/exif-handling.txt | 97 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100755 devel-docs/exif-handling.txt (limited to 'devel-docs/exif-handling.txt') diff --git a/devel-docs/exif-handling.txt b/devel-docs/exif-handling.txt new file mode 100755 index 0000000..e196752 --- /dev/null +++ b/devel-docs/exif-handling.txt @@ -0,0 +1,97 @@ + How GIMP should handle EXIF data + + Bill Skaggs 1/2/05 + +This is a summary of how an image editing program is supposed to +handle each of the EXIF fields, according to the EXIF specs. Note +that this expresses my understanding based on a quick reading, and +should not be taken as gospel. For details on the contents of each of +these fields, consult the formal EXIF specifications, available from +http://www.exif.org/specifications.html. + +(Note: according to the EXIF specs, an EXIF jpeg file must have a name +that is ASCII, in 8.3 format, with extension .JPG, but of course we +are not going to enforce this.) + + + +Fields that should be used to set up the GIMP image when an EXIF file +is loaded, either by using them to configure the image (e.g., +orientation), or by placing them in parasites that can be accessed by +non-exif-aware functions. + +Orientation +XResolution +YResolution +ResolutionUnit +ImageDescription +Artist +Copyright +Colorspace +ComponentsConfiguration +UserComment +SubjectArea +SubjectLocation +ImageUniqueID +PixelXDimension +PixelYDimension + + + +Fields that should be modified by GIMP when an EXIF jpeg file is +saved. A letter "M" indicates fields whose presence is mandatory +according to the spec. + +Orientation +XResolution (M) +YResolution (M) +ResolutionUnit (M) +Software +DateTime +ImageDescription +Artist +Colorspace (M) +PixelXDimension (M) +PixelYDimension (M) +ComponentsConfiguration (M) +UserComment +SubsecTime +SubjectArea +SubjectLocation +FileSource +ImageUniqueID +thumbnail Compression (M) +thumbnail XResolution (M) +thumbnail YResolution (M) +thumbnail JPEGInterchangeFormat (M) +thumbnail JPEGInterchangeFormatLength (M) + + + +Fields that should be used and saved related to color management: + +TransferFunction +WhitePoint +PrimaryChromaticity +YCbCrCoefficients +ReferenceBlackWhite + + + +Fields that should be deleted if they exist when saving a file as +jpeg, because they only apply to uncompressed (TIFF) data. This +applies both to the main image and to the thumbnail, if there is one. + +ImageWidth +ImageLength +BitsPerSample +Compression +SamplesPerPixel +PhotometricInterpretation +StripOffsets +PlanarConfiguration +YCbCrSubSampling + + + +Any field not mentioned here should be passed through unchanged. -- cgit v1.2.3