From c898ffceebcf7723e3d4805bf03cd890f4ba50fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Olivier=20Cr=C3=AAte?= <olivier.crete@collabora.com>
Date: Tue, 4 May 2021 15:50:59 -0400
Subject: [PATCH] video: Add API to parse the image orientation from a
 GstTagList

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1088>
---
 .../gst-libs/gst/video/video.c                | 49 +++++++++++++++++++
 .../gst-libs/gst/video/video.h                |  5 ++
 2 files changed, 54 insertions(+)

diff --git a/subprojects/gst-plugins-base/gst-libs/gst/video/video.c b/subprojects/gst-plugins-base/gst-libs/gst/video/video.c
index 21cc5a157c..4e20baa6c8 100644
--- a/subprojects/gst-plugins-base/gst-libs/gst/video/video.c
+++ b/subprojects/gst-plugins-base/gst-libs/gst/video/video.c
@@ -237,3 +237,52 @@ gst_video_orientation_method_get_type (void)
 
   return (GType) video_orientation_method_type;
 }
+
+/**
+ * gst_video_orientation_from_tag:
+ * @taglist: A #GstTagList
+ * @method: The location where to return the orientation.
+ *
+ * Parses the "image-orientation" tag and transforms it into the
+ * #GstVideoOrientationMethod enum.
+ *
+ * Returns: TRUE if there was a valid "image-orientation" tag in the taglist.
+ *
+ * Since: 1.20
+ */
+gboolean
+gst_video_orientation_from_tag (GstTagList * taglist,
+    GstVideoOrientationMethod * method)
+{
+  gchar *orientation;
+  gboolean ret = TRUE;
+
+  g_return_val_if_fail (GST_IS_TAG_LIST (taglist), FALSE);
+  g_return_val_if_fail (method != NULL, FALSE);
+
+  if (!gst_tag_list_get_string (taglist, "image-orientation", &orientation))
+    return FALSE;
+
+  if (!g_strcmp0 ("rotate-0", orientation))
+    *method = GST_VIDEO_ORIENTATION_IDENTITY;
+  else if (!g_strcmp0 ("rotate-90", orientation))
+    *method = GST_VIDEO_ORIENTATION_90R;
+  else if (!g_strcmp0 ("rotate-180", orientation))
+    *method = GST_VIDEO_ORIENTATION_180;
+  else if (!g_strcmp0 ("rotate-270", orientation))
+    *method = GST_VIDEO_ORIENTATION_90L;
+  else if (!g_strcmp0 ("flip-rotate-0", orientation))
+    *method = GST_VIDEO_ORIENTATION_HORIZ;
+  else if (!g_strcmp0 ("flip-rotate-90", orientation))
+    *method = GST_VIDEO_ORIENTATION_UR_LL;
+  else if (!g_strcmp0 ("flip-rotate-180", orientation))
+    *method = GST_VIDEO_ORIENTATION_VERT;
+  else if (!g_strcmp0 ("flip-rotate-270", orientation))
+    *method = GST_VIDEO_ORIENTATION_UL_LR;
+  else
+    ret = FALSE;
+
+  g_free (orientation);
+
+  return ret;
+}
diff --git a/subprojects/gst-plugins-base/gst-libs/gst/video/video.h b/subprojects/gst-plugins-base/gst-libs/gst/video/video.h
index 24a3a7319f..a1a6d1a422 100644
--- a/subprojects/gst-plugins-base/gst-libs/gst/video/video.h
+++ b/subprojects/gst-plugins-base/gst-libs/gst/video/video.h
@@ -172,6 +172,11 @@ GstSample *   gst_video_convert_sample       (GstSample     * sample,
                                               GstClockTime    timeout,
                                               GError       ** error);
 
+
+GST_VIDEO_API
+gboolean gst_video_orientation_from_tag (GstTagList * taglist,
+                                         GstVideoOrientationMethod * method);
+
 G_END_DECLS
 
 #include <gst/video/colorbalancechannel.h>