cleanup exif data (#16491)

* cleanup exif data

See discussion in #16479

It turned out that exiv2 gives a whole zoo of manufacturer specific values for the white balance. In some cases where a camera value has no representation by exiv2, the color temperature value is  returned, in a not well formated way with trailing spaces.

Improvements/fixes:

- remove trailing spaces
- `not defined` and `unknown` are now treated as the darktable default `unnamed`
- entries are now compared case-insensitive before they get written to the database. This avoids having duplicates like `Cloudy` and `CLOUDY`
- if a numeric exif value `n` has no textual representation in exiv2 the returned string is `(n)` which is pretty much useless so it is discarded now
- fixed a bug in `collection.c` where `strlen()` was used instead of `g_utf8_strlen()`. This failed on strings containing special characters (e.g. german umlauts)

src/common/collection.c

@@ -1245,12 +1245,12 @@ static gchar *_add_wildcards(const gchar *text)
   gchar *cam1 = NULL;
   gchar *cam2 = NULL;
   if(g_str_has_prefix(text, "\""))
-    cam1 = g_utf8_substring(text, 1, strlen(text));
+    cam1 = g_utf8_substring(text, 1, g_utf8_strlen(text, -1));
   else
     cam1 = g_strdup_printf("%%%s", text);
 
   if(g_str_has_suffix(cam1, "\""))
-    cam2 = g_utf8_substring(cam1, 0, strlen(cam1)-1);
+    cam2 = g_utf8_substring(cam1, 0, g_utf8_strlen(cam1, -1)-1);
   else
     cam2 = g_strdup_printf("%s%%", cam1);
 

src/common/exif.cc

@@ -425,8 +425,27 @@ static void _strlcpy_to_utf8(char *dest, size_t dest_max,
   {
     g_strlcpy(dest, str.c_str(), dest_max);
   }
+  g_strstrip(dest);
 }
 
+// if a numerical exif value n has no string repsentation in exiv2
+// the returned string is a useless "(n)" which can be descarded
+static void _exif_value_str(const int value,
+                            char *dest, 
+                            size_t dest_max,
+                            Exiv2::ExifData::const_iterator &pos,
+                            Exiv2::ExifData &exifData)
+{
+  _strlcpy_to_utf8(dest, dest_max, pos, exifData);
+  gchar *str_value = g_strdup_printf("(%d)", value);
+  if(g_strcmp0(dest, str_value) == 0)
+  {
+    dest[0] = '\0';
+  }
+  g_free(str_value);
+}
+
+
 // function to remove known dt keys and subtrees from xmpdata, so not
 // to append them twice this should work because dt first reads all
 // known keys
@@ -909,7 +928,7 @@ static gboolean _check_lens_correction_data(Exiv2::ExifData &exifData, dt_image_
         const float kc = posc->toFloat(i + 1);
         const float kv = posv->toFloat(i + 1);
         // check that the knots position is the same for distortion, ca and vignetting,
-        if (kd != kc || kd != kv)
+        if(kd != kc || kd != kv)
         {
           img->exif_correction_type = CORRECTION_TYPE_NONE;
           break;
@@ -943,7 +962,7 @@ static gboolean _check_lens_correction_data(Exiv2::ExifData &exifData, dt_image_
         if(i != 0) kc = posc->toFloat(i);
         const float kv = posv->toFloat(i + 1);
         // check that the knots position is the same for distortion, ca and vignetting,
-        if (kd != kc || kd != kv)
+        if(kd != kc || kd != kv)
         {
           img->exif_correction_type = CORRECTION_TYPE_NONE;
           break;
@@ -987,7 +1006,7 @@ static gboolean _check_lens_correction_data(Exiv2::ExifData &exifData, dt_image_
       {
         const float kd = pos->toFloat(i);
         img->exif_correction_data.olympus.dist[i] = kd;
-        if (kd != 0 && i < 3)
+        if(kd != 0 && i < 3)
         {
           // Assume it's valid if any of the first three elements are nonzero. Ignore the
           // fourth element since the null value for no correction is '0 0 0 1'
@@ -1010,7 +1029,7 @@ static gboolean _check_lens_correction_data(Exiv2::ExifData &exifData, dt_image_
       {
         const float kc = pos->toFloat(i);
         img->exif_correction_data.olympus.ca[i] = kc;
-        if (kc != 0)
+        if(kc != 0)
         {
           img->exif_correction_type = CORRECTION_TYPE_OLYMPUS;
           img->exif_correction_data.olympus.has_ca = TRUE;
@@ -1587,22 +1606,35 @@ static bool _exif_decode_exif_data(dt_image_t *img, Exiv2::ExifData &exifData)
 
     if((pos = Exiv2::whiteBalance(exifData)) != exifData.end() && pos->size())
     {
-      _strlcpy_to_utf8(img->exif_whitebalance, sizeof(img->exif_whitebalance), pos, exifData);
+      const int value = pos->toLong();
+      _exif_value_str(value, img->exif_whitebalance, sizeof(img->exif_whitebalance), pos, exifData);
     }
 
     if(FIND_EXIF_TAG("Exif.Photo.Flash"))
     {
-      _strlcpy_to_utf8(img->exif_flash, sizeof(img->exif_flash), pos, exifData);
+      const int value = pos->toLong();
+      if(value != 0)
+      {
+        _strlcpy_to_utf8(img->exif_flash, sizeof(img->exif_flash), pos, exifData);
+      }
     }
 
     if(FIND_EXIF_TAG("Exif.Photo.ExposureProgram"))
     {
-      _strlcpy_to_utf8(img->exif_exposure_program, sizeof(img->exif_exposure_program), pos, exifData);
+      const int value = pos->toLong();
+      if(value != 0)
+      {
+        _exif_value_str(value, img->exif_exposure_program, sizeof(img->exif_exposure_program), pos, exifData);
+      }
     }
 
     if(FIND_EXIF_TAG("Exif.Photo.MeteringMode"))
     {
-      _strlcpy_to_utf8(img->exif_metering_mode, sizeof(img->exif_metering_mode), pos, exifData);
+      const int value = pos->toLong();
+      if(value != 0)
+      {
+        _exif_value_str(value, img->exif_metering_mode, sizeof(img->exif_metering_mode), pos, exifData);
+      }
     }
 
     char datetime[DT_DATETIME_LENGTH];
@@ -5027,7 +5059,7 @@ const std::pair<std::array<float, 4>, bool> getRegionNormalized(
   float y = yIt->toFloat() * imgHeight;
 
   /* MWG regions use (x,y) as the center of the region */
-  if (regionType == RegionType::MWG)
+  if(regionType == RegionType::MWG)
   {
     x -= w/2;
     y -= h/2;

src/common/image.c

@@ -3200,7 +3200,7 @@ static int32_t _image_get_set_name_id(const char *table,
 
   char *query = g_strdup_printf("SELECT id"
                                 "  FROM main.%s"
-                                "  WHERE name = '%s'",
+                                "  WHERE LOWER(name) = LOWER('%s')",
                                 table,
                                 name);