From 0e36d26dad1143877d2cccb588e630271b3bc9b4 Mon Sep 17 00:00:00 2001
From: Jacopo Mondi <jacopo@jmondi.org>
Date: Wed, 22 Apr 2020 09:46:05 +0200
Subject: libcamera: v4l2_subdevice: Implement getSelection()
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Implement V4L2Subdevice::getSelection() to support retrieving selection
rectangles from the V4L2 subdevice.
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
---
src/libcamera/include/v4l2_subdevice.h | 2 ++
src/libcamera/v4l2_subdevice.cpp | 36 ++++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 9a5c812d..27ba5b17 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -46,6 +46,8 @@ public:
const MediaEntity *entity() const { return entity_; }
+ int getSelection(unsigned int pad, unsigned int target,
+ Rectangle *rect);
int setSelection(unsigned int pad, unsigned int target,
Rectangle *rect);
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index e8623d58..06bc430f 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -133,6 +133,42 @@ int V4L2Subdevice::open()
* \return The subdevice's associated media entity.
*/
+/**
+ * \brief Get selection rectangle \a rect for \a target
+ * \param[in] pad The 0-indexed pad number the rectangle is retrieved from
+ * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
+ * \param[out] rect The retrieved selection rectangle
+ *
+ * \todo Define a V4L2SelectionTarget enum for the selection target
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
+ Rectangle *rect)
+{
+ struct v4l2_subdev_selection sel = {};
+
+ sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
+ sel.pad = pad;
+ sel.target = target;
+ sel.flags = 0;
+
+ int ret = ioctl(VIDIOC_SUBDEV_G_SELECTION, &sel);
+ if (ret < 0) {
+ LOG(V4L2, Error)
+ << "Unable to get rectangle " << target << " on pad "
+ << pad << ": " << strerror(-ret);
+ return ret;
+ }
+
+ rect->x = sel.r.left;
+ rect->y = sel.r.top;
+ rect->width = sel.r.width;
+ rect->height = sel.r.height;
+
+ return 0;
+}
+
/**
* \brief Set selection rectangle \a rect for \a target
* \param[in] pad The 0-indexed pad number the rectangle is to be applied to
--
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