Add HAS_EXIF define

This brings a new HAS_EXIF define which is present when
EXIF information are available. Templates have been modified
to inform user when not available.

The test for EXIF metadata presence is fairly basic, we only look
for aperture, focal length and exposure time attributes. This might
be a subject to change in the future.

5 files changed, 59 insertions, 2 deletions

diff --git a/src/generators.c b/src/generators.c
index 1d05eea..5fe87fe 100644
--- a/src/generators.c
+++ b/src/generators.c
@@ -707,6 +707,11 @@ write_html_image (TGallerySetup *setup,
     if (exif == NULL)
       log_error ("write_html_image: error getting exif data from file \"%s\"\n", img_dst);
   }
+  /*  Test for basic EXIF keys presence  */
+  if (exif != NULL && exif_has_key (exif, EXIF_APERTURE) &&
+                      exif_has_key (exif, EXIF_FOCAL_LENGTH) &&
+                      exif_has_key (exif, EXIF_EXPOSURE))
+    g_hash_table_replace (defines, g_strdup ("HAS_EXIF"), g_strdup (""));
 
   /*  Retrieve image sizes of preview and original image  */
   get_image_sizes (img_dst, &img_w, &img_h, setup->autorotate);
diff --git a/src/jpeg-utils.cpp b/src/jpeg-utils.cpp
index 031ecc0..389b8e4 100644
--- a/src/jpeg-utils.cpp
+++ b/src/jpeg-utils.cpp
@@ -197,6 +197,41 @@ get_exif_data_fixed (ExifData *exif, const gchar *key)
   return get_exif_data (exif, key);
 }
 
+/*
+ *   Returns TRUE if the image contains the key specified
+ */
+gboolean
+exif_has_key (ExifData *exif, const gchar *key)
+{
+  g_return_val_if_fail (exif != NULL, FALSE);
+  g_return_val_if_fail (key != NULL, FALSE);
+
+  try {
+    if (g_strcmp0 (key, JPEG_COMMENT) == 0) {
+      return (! exif->image->comment().empty());
+    }
+
+    if (g_str_has_prefix (key, "Exif.")) {
+      Exiv2::ExifData &exifData = exif->image->exifData();
+      if (! exifData.empty()) {
+        return (! exifData[key].toString().empty());
+      }
+    }
+
+    if (g_str_has_prefix (key, "Iptc.")) {
+      Exiv2::IptcData &iptcData = exif->image->iptcData();
+      if (! iptcData.empty()) {
+        return (! iptcData[key].toString().empty());
+      }
+    }
+
+    return FALSE;
+  }
+  catch (...) {
+    return FALSE;
+  }
+}
+
 
 static void
 autorotate_image (MagickWand *magick_wand)
diff --git a/src/jpeg-utils.h b/src/jpeg-utils.h
index 05a6a49..7cec3a7 100644
--- a/src/jpeg-utils.h
+++ b/src/jpeg-utils.h
@@ -62,6 +62,11 @@ void exif_data_free (ExifData *data);
 gchar * get_exif_data (ExifData *exif, const gchar *key);
 gchar * get_exif_data_fixed (ExifData *exif, const gchar *key);
 
+/*
+ *   Returns TRUE if the image contains the key specified
+ */
+gboolean exif_has_key (ExifData *exif, const gchar *key);
+
 
 /*
  *   resize_image: resize image pointed by src and save result to dst
diff --git a/templates/styles.css b/templates/styles.css
index b96f19f..ea337f9 100644
--- a/templates/styles.css
+++ b/templates/styles.css
@@ -175,6 +175,10 @@ div.exif td {
    font-weight: bold;
 }
 
+div.no_exif {
+   padding: 1em 0 0 2.6em;
+   font-size: 80%;
+}
 
 /******   GENERAL CLASSES   ******/
 div.position_marker {
diff --git a/templates/template_picture.html b/templates/template_picture.html
index 07c79ec..d164b6d 100644
--- a/templates/template_picture.html
+++ b/templates/template_picture.html
@@ -20,7 +20,9 @@
     <span class="navposspacer"></span>
     <a href="$(LINK_PREV)">&lt; Previous</a> :: <a href="$(LINK_NEXT)">Next &gt;</a>
   </div>
-  <div class="navexif">ISO <!-- $(get_exif_value_fixed("Exif.Photo.ISOSpeedRatings")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.ExposureTime")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.FNumber")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.FocalLength")) --></div>
+  <!-- $(ifdef(HAS_EXIF)) -->
+    <div class="navexif">ISO <!-- $(get_exif_value_fixed("Exif.Photo.ISOSpeedRatings")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.ExposureTime")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.FNumber")) --> :: <!-- $(get_exif_value_fixed("Exif.Photo.FocalLength")) --></div>
+  <!-- $(endif(HAS_EXIF)) -->
 </div>
 
 
@@ -45,7 +47,8 @@
   <!--  ##  EXIF  -->
   <div class="exif">
     <div id="exif_table" style="display: none;">
-      :: <a href="javascript: set_exif_table_visibility('no'); write_exif_table_cookie('no');">Hide EXIF</a>
+      :: <a href="javascript: set_exif_table_visibility('no'); write_exif_table_cookie('no');">Hide EXIF</a><br/>
+      <!-- $(ifdef(HAS_EXIF)) -->
       <table><tbody>
         <tr><td>Date: </td>            <td><!-- $(get_exif_value_fixed("Exif.Photo.DateTimeOriginal")) --></td></tr>
         <tr><td>Camera: </td>          <td><!-- $(get_exif_value_fixed("Exif.Image.Model")) --></td></tr>
@@ -55,6 +58,11 @@
         <tr><td>Exposure time: </td>   <td><!-- $(get_exif_value_fixed("Exif.Photo.ExposureTime")) --></td></tr>
         <tr><td>Flash: </td>           <td><!-- $(get_exif_value_fixed("Exif.Photo.Flash")) --></td></tr>
       </tbody></table>
+      <!-- $(else(HAS_EXIF)) -->
+      <div class="no_exif">
+        No EXIF information available.
+      </div>
+      <!-- $(endif(HAS_EXIF)) -->
     </div>
     <div id="exif_line" style="display: block;">
       :: <a href="javascript: set_exif_table_visibility('yes'); write_exif_table_cookie('yes');">Show EXIF</a>