[wp-meta] [Making WordPress.org] #820: Codex page for wp_read_image_metadata gives wrong order for image meta determination

[Making WordPress.org]

#820: Codex page for wp_read_image_metadata gives wrong order for image meta
determination
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Reporter:  theMikeD  |      Owner:
    Type:  defect    |     Status:  new
Priority:  normal    |  Component:  Codex
Keywords:            |
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 The codex page for `wp_read_image_metadata()` describes how the various
 meta values are determined by reading IPTC and EXIF info embedded into the
 image header. Specifically it outlines the order used to populate the
 image metadata. The order shown is wrong for title, copyright, caption and
 credit. I've confirmed that it's wrong by making a logic block of the
 code, and by testing with the various IPTC and EXIF header info set.

 For example, for "title" codex lists the following as the order of
 preference:
 1. EXIF Title field
 2. IPTC Headline field (2#105)
 3. IPTC Title field (2#005)
 4. IPTC Caption field (2#120) but only if less than 80 characters
 5. EXIF ImageDescription field but only if less than 80 characters

 Looking at the code, the correct order is
 1. IPTC:Headline
 2. IPTC:Title
 3. IPTC:Description if less than 80 characters
 4. EXIF:Title
 5. EXIF:Description if less than 80 characters

 This is confirmed additionally by looking at the comments in the code, one
 of which states:

 {{{
          * Read IPTC first, since it might contain data not available in
 exif such
          * as caption, description etc.
 }}}


 Here are the correct orders:
 '''title:'''
 1. IPTC:Headline
 2. IPTC:Title
 3. IPTC:Description if less than 80 characters
 4. EXIF:Title
 5. EXIF:ImageDescription if less than 80 characters

 '''caption:'''
 1. IPTC:Description
 2. EXIF:UserComment if title is unset AND EXIF:ImageDescription is less
 than 80 characters
 3. EXIF:ImageDescription if title is set OR EXIF:ImageDescription is more
 than 80 characters
 4. EXIF:Comments if title !== EXIF:Comments

 '''credit:'''
 1. IPTC:Credit
 2. IPTC:Creator
 3. EXIF:Artist
 4. EXIF:Author

 '''copyright:'''
 1. IPTC:Copyright
 2. EXIF:Copyright

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Ticket URL: <https://meta.trac.wordpress.org/ticket/820>
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