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41 lines
1.6 KiB
Plaintext
41 lines
1.6 KiB
Plaintext
XMP support
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XMP support is controlled with the --enable-xmp and
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--disable-xmp options of the configure script. Building Exiv2
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with XMP support requires the Expat XML parser library, which
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is widely available. The --with-expat configure option can
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be used if it is installed in a non-standard directory.
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Top-level Exiv2 classes to access XMP metadata are XmpData,
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Xmpdatum and XmpKey. They work similar to the corresponding
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Exif and IPTC classes. The property-repository is XmpProperties.
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In addition to the expected new members, class Image also
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has an interface to access the raw XMP packet.
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All XMP value types are supported: Simple types, structures,
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arrays, property qualifiers and language alternatives.
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XMP properties are accessed through keys of the form
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"Xmp.<Prefix>.<PropertyPath>", where <Prefix> is the preferred
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(or rather, registered) prefix for a schema namespace and
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<PropertyPath> is the path of the XMP node. In its most basic
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form, to address simple properties, <PropertyPath> is the name
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of the property. In general, <PropertyPath> can be used to
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address any XMP node, including array items, structure fields
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qualifiers and deeply nested properties.
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Any properties in known namespaces are supported and additional
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namespaces can be registered.
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The specialized Exiv2 values XmpArrayValue and LangAltValue are
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provided to simplify the use of XMP properties.
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See xmpsample.cpp for examples of how to set various types of
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XMP properties.
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Note: Unlike Exif and IPTC tags, XMP properties do not have
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a tag number.
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Todo: Conversion between XMP and Exif/IPTC metadata.
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