From 008ab7fc0f43161e0eedfddbaa80fe28c4f9ff13 Mon Sep 17 00:00:00 2001
From: Dennis Real <github@tildepipe.org>
Date: Fri, 4 Jan 2013 00:09:31 +0100
Subject: Workaround for broken Flash Exposure Compensation

---
 src/exif_cfg.h   |  2 +-
 src/exif_nikon.c | 35 +++++++++++++++++++++++++++++++++--
 2 files changed, 34 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/exif_cfg.h b/src/exif_cfg.h
index a3344bc..a961147 100644
--- a/src/exif_cfg.h
+++ b/src/exif_cfg.h
@@ -72,8 +72,8 @@ const unsigned int Exif_makernote_nikon_tag_list [] =
   6,
   8,   /* Flash Setting */
   9,   /* Flash Mode */
-  24,  /* Flash exposure bracket value */
   135, /* Flash used */
+  18,  /* Flash Exposure Comp */
   168, /* Flash info: control mode */
 
   2,   /* ISO. Has some more info than EXIF_TAG_ISO_SPEED_RATINGS but also fails on Lo.1 */  
diff --git a/src/exif_nikon.c b/src/exif_nikon.c
index 21a2f08..7ee6e86 100644
--- a/src/exif_nikon.c
+++ b/src/exif_nikon.c
@@ -107,6 +107,7 @@ static void exn_get_prim_af_pt(unsigned int phasedetectaf,
                                char * buffer,
                                unsigned int maxsize);
 static void exn_get_flash_output(unsigned int flashoutput, char * buffer, unsigned int maxsize);
+static void exn_get_mnote_nikon_18(ExifData *ed, char * buffer, unsigned int maxsize);
 static void exn_get_mnote_nikon_34(ExifData *ed, char * buffer, unsigned int maxsize);
 static void exn_get_mnote_nikon_35(ExifData *ed, char * buffer, unsigned int maxsize);
 static void exn_get_mnote_nikon_168(ExifData *ed, char * buffer, unsigned int maxsize);
@@ -199,6 +200,23 @@ static void exn_get_flash_output(unsigned int flashoutput, char * buffer, unsign
 
 
 
+/* get ActiveD-Lighting (18) info */
+static void exn_get_mnote_nikon_18(ExifData *ed, char * buffer, unsigned int maxsize)
+{
+
+  char buf[EXIF_STD_BUF_LEN];
+  float data = 0;
+
+  buf[0] = '\0';
+  exif_get_mnote_tag(ed, 18, buf, sizeof(buf));
+
+  sscanf(buf, "Flash Exposure Compensation: %f", &data); /* libexif buggy here. fix conversion */
+
+  snprintf(buffer, maxsize, "FlashExposureCompensation: %.1f\n", ((float)((signed char)round(data*6.0))) / 6.0 );
+}
+
+
+
 /* get ActiveD-Lighting (34) info */
 static void exn_get_mnote_nikon_34(ExifData *ed, char * buffer, unsigned int maxsize)
 {
@@ -321,13 +339,16 @@ static void exn_get_mnote_nikon_168(ExifData *ed, char * buffer, unsigned int ma
   unsigned int exn_fcm = (EXN_FLASH_CONTROL_MODES_MAX-1); /* default to N/A */
   unsigned int flashoutput = 0;
   unsigned int externalflashflags = 0;
+  unsigned int flashcompensation = 0;
 
   /* libexif does not support flash info 168 yet. so we have to parse the debug data :-( */
   buf[0] = '\0';
   exif_get_mnote_tag(ed, 168, buf, sizeof(buf));
-  sscanf(buf, "(null): %u bytes unknown data: 303130%02X%*8s%02X%02X%02X", &length, &version, &externalflashflags, &exn_fcm, &flashoutput);
+  sscanf(buf, "(null): %u bytes unknown data: 303130%02X%*8s%02X%02X%02X%02X", &length, &version, &externalflashflags, &exn_fcm, &flashoutput, &flashcompensation);
   exn_fcm = exn_fcm & EXN_FLASH_CONTROL_MODE_MASK;
 
+  /* printf("%s - %d %d %d %d\n", buf, externalflashflags, exn_fcm, flashoutput, (signed char)flashcompensation); */
+
   if ( (exn_fcm < EXN_FLASH_CONTROL_MODES_MAX)
        && ( ((length == 22) && (version == '3'))      /* Nikon FlashInfo0103 */
             || ((length == 22) && (version == '4'))   /* Nikon FlashInfo0104 */
@@ -422,7 +443,7 @@ void exn_get_mnote_nikon_tags(ExifData *ed, unsigned int tag, char * buffer, uns
     /* show only if flash was used */
     case 8:   /* Flash Setting */
     case 9:   /* Flash Mode */
-    case 24:  /* Flash exposure bracket value */
+    case 27:  /* Flash exposure bracket value */
     case 135: /* Flash used */
     {
       if ( !(strcmp("Flash: Flash did not fire\n", buf) == 0) )
@@ -433,6 +454,16 @@ void exn_get_mnote_nikon_tags(ExifData *ed, unsigned int tag, char * buffer, uns
     }
     break;
 
+    case 18:  /* FlashExposureComp */
+    {
+      if ( !(strcmp("Flash: Flash did not fire\n", buf) == 0) )
+      {
+        /* show only if flash was fired */
+        exn_get_mnote_nikon_18(ed, buffer, maxsize);
+      }
+    }
+    break;
+    
     case 34:
     {
       /* ActiveD-Lighting */
-- 
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