@@ -13,6 +13,7 @@
#include <set>
#include <stdint.h>
#include <string>
+#include <unordered_set>
#include <libcamera/base/class.h>
#include <libcamera/base/flags.h>
@@ -122,6 +123,7 @@ public:
const std::string &id() const;
+ Signal<Request *, std::unordered_set<const ControlId *>> metadataAvailable;
Signal<Request *, FrameBuffer *> bufferCompleted;
Signal<Request *> requestCompleted;
Signal<> disconnected;
@@ -886,6 +886,48 @@ const std::string &Camera::id() const
return _d()->id_;
}
+/**
+ * \var Camera::metadataAvailable
+ * \brief Signal emitted when metadata for a request are available
+ *
+ * The metadataAvailable signal notifies applications about the availability
+ * of metadata for a request before the request completes.
+ *
+ * As metadata results could be large in size, the signal transports the ids
+ * of the metadata that have just been made available, but the actual control
+ * values are stored in the Camera::metadata() list.
+ *
+ * Applications can access the value of the newly available metadata results
+ * with:
+ *
+ * \code
+
+ void metadataAvailableHandler(Request *request,
+ std::unordered_set<const ControlId *> ids)
+ {
+ const ControlList &metadata = request->metadata();
+
+ for (const auto id : ids) {
+ ControlValue &value = metadata.get(id->id());
+
+ ....
+ }
+ }
+ \endcode
+ *
+ * This signal is emitted multiple times for the same request, it is in facts
+ * emitted by the framework every time a new metadata list is made available
+ * by the Camera to the application.
+ *
+ * The sum of all metadata lists reported through this signal is equal to
+ * Request::metadata() list when the Request completes.
+ *
+ * Application can opt-in to handle this signal to receive fast notifications
+ * of metadata availability or can equally access the full metadata list
+ * at Request complete time through Request::metadata() if they have no interest
+ * in early metadata notification.
+ */
+
/**
* \var Camera::bufferCompleted
* \brief Signal emitted when a buffer for a request queued to the camera has
Add a new signal to the Camera class that allows applications to receive notifications for early completion of metadata results. To avoid expensive copies of the metadata results the signal transports the ids of the metadata keys that are ready. Applications can use these ids to access the metadata results from Request::metadata(). The signal is an opt-in feature for applications and the sum of all metadata results notified through this signal is available in Request::metadata() at request completion time. Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> --- include/libcamera/camera.h | 2 ++ src/libcamera/camera.cpp | 42 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+)