3 files changed, 116 insertions, 1 deletions
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index b940647d..59ee3c40 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -291,7 +291,8 @@ bool SensorConfiguration::isValid() const
  * \brief Create an empty camera configuration
  */
 CameraConfiguration::CameraConfiguration()
-	: transform(Transform::Identity), config_({})
+	: transform(Transform::Identity), orientation(Orientation::Rotate0),
+	  config_({})
 {
 }
 
@@ -553,6 +554,21 @@ CameraConfiguration::Status CameraConfiguration::validateColorSpaces(ColorSpaceF
  */
 
 /**
+ * \var CameraConfiguration::orientation
+ * \brief The desired orientation of the images produced by the camera
+ *
+ * The orientation field is a user-specified 2D plane transformation that
+ * specifies how the application wants the camera images to be rotated in
+ * the memory buffers.
+ *
+ * If the orientation requested by the application cannot be obtained, the
+ * camera will not rotate or flip the images, and the validate() function will
+ * Adjust this value to the native image orientation produced by the camera.
+ *
+ * By default the orientation field is set to Orientation::Rotate0.
+ */
+
+/**
  * \var CameraConfiguration::config_
  * \brief The vector of stream configurations
  */
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index b24f8296..d0e26f6b 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -34,6 +34,7 @@ libcamera_sources = files([
     'mapped_framebuffer.cpp',
     'media_device.cpp',
     'media_object.cpp',
+    'orientation.cpp',
     'pipeline_handler.cpp',
     'pixel_format.cpp',
     'process.cpp',
diff --git a/src/libcamera/orientation.cpp b/src/libcamera/orientation.cpp
new file mode 100644
index 00000000..a3465383
--- /dev/null
+++ b/src/libcamera/orientation.cpp
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2023, Ideas On Board Oy
+ *
+ * orientation.cpp - Image orientation
+ */
+
+#include <libcamera/orientation.h>
+
+#include <array>
+#include <string>
+
+/**
+ * \file libcamera/orientation.h
+ * \brief Image orientation definition
+ */
+
+namespace libcamera {
+
+/**
+ * \enum Orientation
+ * \brief The image orientation in a memory buffer
+ *
+ * The Orientation enumeration describes the orientation of the images
+ * produced by the camera pipeline as they get received by the application
+ * inside memory buffers.
+ *
+ * The image orientation expressed using the Orientation enumeration can be then
+ * inferred by applying to a naturally oriented image a multiple of a 90 degrees
+ * rotation in the clockwise direction from the origin and then by applying an
+ * optional horizontal mirroring.
+ *
+ * The enumeration numerical values follow the ones defined by the EXIF
+ * Specification version 2.32, Tag 274 "Orientation", while the names of the
+ * enumerated values report the rotation and mirroring operations performed.
+ *
+ * For example, Orientation::Rotate90Mirror describes the orientation obtained
+ * by rotating the image 90 degrees clockwise first and then applying a
+ * horizontal mirroring.
+ */
+
+/**
+ * \brief Return the orientation representing a rotation of the given angle
+ * clockwise
+ * \param[in] angle The angle of rotation in a clockwise sense. Negative values
+ * can be used to represent anticlockwise rotations
+ * \param[out] success Set to `true` if the angle is a multiple of 90 degrees,
+ * otherwise `false`
+ * \return The orientation corresponding to the rotation if \a success was set
+ * to `true`, otherwise the `Rotate0` orientation
+ */
+Orientation orientationFromRotation(int angle, bool *success)
+{
+	angle = angle % 360;
+	if (angle < 0)
+		angle += 360;
+
+	if (success != nullptr)
+		*success = true;
+
+	switch (angle) {
+	case 0:
+		return Orientation::Rotate0;
+	case 90:
+		return Orientation::Rotate90;
+	case 180:
+		return Orientation::Rotate180;
+	case 270:
+		return Orientation::Rotate270;
+	}
+
+	if (success != nullptr)
+		*success = false;
+
+	return Orientation::Rotate0;
+}
+
+/**
+ * \brief Prints human-friendly names for Orientation items
+ * \param[in] out The output stream
+ * \param[in] orientation The Orientation item
+ * \return The output stream \a out
+ */
+std::ostream &operator<<(std::ostream &out, const Orientation &orientation)
+{
+	constexpr std::array<const char *, 9> orientationNames = {
+		"", /* Orientation starts counting from 1. */
+		"Rotate0", "Rotate0Mirror",
+		"Rotate180", "Rotate180Mirror",
+		"Rotate90Mirror", "Rotate270",
+		"Rotate270Mirror", "Rotate90",
+	};
+
+	out << orientationNames[static_cast<unsigned int>(orientation)];
+	return out;
+}
+
+} /* namespace libcamera */