Add support for writing external EXIF metadata back to images

Turned off by default, this will copy all data from supplied external
EXIF metadata file back to all generated image files. All user overrides
are still applied on top of it.

Another reason for turning this off is file size concern, target image
files would carry a lot more information that may not be always needed and
would increase total amount of data transferred.

2 files changed, 10 insertions, 2 deletions

diff --git a/sample/src/CIAF_1/index.xml b/sample/src/CIAF_1/index.xml
index 24433fd..5d9ad5a 100644
--- a/sample/src/CIAF_1/index.xml
+++ b/sample/src/CIAF_1/index.xml
@@ -108,7 +108,8 @@
                                   Photo editors and RAW workflow software usually strip big deal of metadata unknown to them. Things like <a href="http://exiv2.org/makernote.html">camera makernote</a> data are usually lost. Yet it may contain interesting information like lens used, crop factor/focal length converted to 35 mm film equivalent or even camera temperature.<br/><br/>
                                   Any format that the Exiv2 library is able to read can be used as a source of EXIF/IPTC information. Use <code>cgg-dirgen</code> to supply external metadata the same way like for supplied thumbnails. By default, the "<code>.exv</code>" file extension is used (default for <code>exiv2</code> commandline tool).<br/><br/>
                                   That said, if you extract and save original metadata and supply them in gallery source XML files, you may be able to display more EXIF information at the end. It's wise to either point to an original RAW file or (to save space) use the <code>exiv2</code> commandline tool to extract the metadata.<br/>
-                                  Example: <code>exiv2 -eeic -f *.cr2</code> extracts EXIF, IPTC and JPEG Comment information to separate .exv files for all Canon CR2 files.
+                                  Example: <code>exiv2 -eeic -f *.cr2</code> extracts EXIF, IPTC and JPEG Comment information to separate .exv files for all Canon CR2 files.<br/><br/>
+                                  Turning the setup key /gallery_setup/images/write_supplied_exif on will write supplied data to all generated image files (except of thumbnails which are always special).
                                   ]]></title_description>
       <metadata>
         <external_exif src="exif/5l9a4978.exv" />
@@ -123,7 +124,9 @@
 
                                   Changes can be made locally for specific item or globally for whole album (with the former taking priority).<br/><br/>
 
-                                  All such changes are written in generated image files in all present metadata fields. This also applies for user supplied images which are normally not supposed to be changed or resized.
+                                  All such changes are written in generated image files in all present metadata fields. This also applies for user supplied images which are normally not supposed to be changed or resized.<br/><br/>
+
+                                  Please note that source timestamps to shift are taken from image file metadata, so that if external EXIF metadata are being used for the particular item but are not set to be written back in the image, datetime shifting may take place on incorrect timestamp. This is normally not a problem since the external EXIF metadata feature was introduced to typically regain lost data from RAW conversion and timestamps should match. This may be subject to change in future.
                                   ]]></title_description>
       <metadata>
         <external_exif src="exif/5l9a4978.exv" />
diff --git a/sample/src/setup.xml b/sample/src/setup.xml
index 75cce85..e85d006 100644
--- a/sample/src/setup.xml
+++ b/sample/src/setup.xml
@@ -25,6 +25,11 @@
     <!--   (allowed values: "yes", "no") default = no                            -->
     <erase_embed_thumbnail value="yes" />
 
+    <!--  in case of supplied external EXIF data, shall these be written in generated images?   -->
+    <!--  This will make image files carry the same data as used for pages                      -->
+    <!--   (allowed values: "yes", "no") default = "no" as this could overwrite important data  -->
+    <write_supplied_exif value="no" />
+
     <!--  don't copy full size (original) images                         -->
     <!--    <nofullsize/> can be used globally for whole gallery,        -->
     <!--    for full album or selectively for each image                 -->