From 7979f76dcd5d5e2340956f6ec3b9009e64648fc1 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Mon, 17 Sep 2012 15:20:47 +0200
Subject: Fix EXIF orientation tag after lossless rotate

---
 ChangeLog   |  7 +++++++
 man/feh.pre | 14 +++++++++++++-
 src/imlib.c | 32 ++++++++++++++++++++++++++++++--
 3 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index af57063..6cefc73 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+git HEAD
+
+    * Set EXIF orientation tag to 1 ("0,0 is top left" aka normal) after
+      running jpegtran. Previously, when doing a lossless rotate, the image
+      was rotated but the corresponding EXIF tag not updated, resulting in
+      wrong image display in programs aware of this EXIF tag.
+
 Thu, 13 Sep 2012 12:00:06 +0200  Daniel Friesel <derf+feh@finalrewind.org>
 
     * Fix freedesktop.org Thumbnail Managing Standard implementation:
diff --git a/man/feh.pre b/man/feh.pre
index e047286..5199151 100644
--- a/man/feh.pre
+++ b/man/feh.pre
@@ -1106,6 +1106,16 @@ away.  See
 .Xr jpegtran 1
 for more about lossless JPEG rotation.
 .
+.Em Note:
+jpegtran does not update EXIF orientation tags. However,
+.Nm
+assumes that you use the feature to normalize image orientation and want it to
+be displayed this way everywhere. After every rotation, it will unconditionally
+set the EXIF orientation to 1
+.Pq Qq 0,0 is top left .
+Should you need to reverse this, see
+.Xr jpegexiforient 1 .
+.
 .It _ Bq flip
 .
 In place editing - vertical flip
@@ -1487,7 +1497,9 @@ but without the flickering.
 .Nm
 requires the
 .Cm jpegtran
-binary
+and
+.Cm jpegexiforient
+binaries
 .Pq usually distributed in Qo libjpeg-progs Qc or similar
 for lossless rotation.
 .
diff --git a/src/imlib.c b/src/imlib.c
index b3abc8a..f247bf7 100644
--- a/src/imlib.c
+++ b/src/imlib.c
@@ -1137,6 +1137,7 @@ void feh_edit_inplace_lossless(winwidget w, int op)
 	int len = strlen(filename) + 1;
 	char *file_str = emalloc(len);
 	int pid, status;
+	int devnull = -1;
 	char op_name[]  = "rotate";     /* message */
 	char op_op[]    = "-rotate";    /* jpegtran option */
 	char op_value[] = "horizontal"; /* jpegtran option's value */
@@ -1156,14 +1157,16 @@ void feh_edit_inplace_lossless(winwidget w, int op)
 	if ((pid = fork()) < 0) {
 		im_weprintf(w, "lossless %s: fork failed:", op_name);
 		exit(1);
-	} else if (pid == 0) {
+	}
+	else if (pid == 0) {
 
 		execlp("jpegtran", "jpegtran", "-copy", "all", op_op, op_value,
 				"-outfile", file_str, file_str, NULL);
 
 		im_weprintf(w, "lossless %s: Is 'jpegtran' installed? Failed to exec:", op_name);
 		exit(1);
-	} else {
+	}
+	else {
 		waitpid(pid, &status, 0);
 
 		if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
@@ -1176,6 +1179,31 @@ void feh_edit_inplace_lossless(winwidget w, int op)
 			return;
 		}
 	}
+	if ((pid = fork()) < 0) {
+		im_weprintf(w, "lossless %s: cannot fix rotation: fork:", op_name);
+		exit(1);
+	}
+	else if (pid == 0) {
+
+		/* discard normal output */
+		devnull = open("/dev/null", O_WRONLY);
+		dup2(devnull, 1);
+
+		execlp("jpegexiforient", "jpegexiforient", "-1", file_str, NULL);
+		im_weprintf(w, "lossless %s: Failed to exec jpegexiforient:", op_name);
+		exit(1);
+	}
+	else {
+		waitpid(pid, &status, 0);
+
+		if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+			im_weprintf(w,
+					"lossless %s: Got exitcode %d from jpegexiforient",
+					status >> 8);
+			free(file_str);
+			return;
+		}
+	}
 	free(file_str);
 }
 
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