basecamerasrc: add virtual function to notify subclass of changing preview caps

Adds a virtual function to basecamerasrc in case subclasses want to be
notified of changing preview caps. This is useful if the subclass wants
to post the preview itself or if it wants to provide a preview buffer
as close to as possible to the user's requested resolution to the
preview generation pipeline.

2 files changed, 29 insertions, 7 deletions

diff --git a/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.c b/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.c
index a26533fc8..cf332be00 100644
--- a/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.c
+++ b/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.c
@@ -201,6 +201,28 @@ gst_base_camera_src_setup_zoom (GstBaseCameraSrc * self)
   bclass->set_zoom (self, zoom);
 }
 
+/**
+ * gst_base_camera_src_setup_preview:
+ * @self: camerasrc bin
+ * @preview_caps: preview caps to set
+ *
+ * Apply preview caps to preview pipeline and to video source.
+ */
+void
+gst_base_camera_src_setup_preview (GstBaseCameraSrc * self,
+    GstCaps * preview_caps)
+{
+  GstBaseCameraSrcClass *bclass = GST_BASE_CAMERA_SRC_GET_CLASS (self);
+
+  if (self->preview_pipeline) {
+    GST_DEBUG_OBJECT (self,
+        "Setting preview pipeline caps %" GST_PTR_FORMAT, self->preview_caps);
+    gst_camerabin_preview_set_caps (self->preview_pipeline, preview_caps);
+  }
+
+  if (bclass->set_preview)
+    bclass->set_preview (self, preview_caps);
+}
 
 /**
  * gst_base_camera_src_get_allowed_input_caps:
@@ -327,13 +349,8 @@ gst_base_camera_src_set_property (GObject * object,
     case PROP_PREVIEW_CAPS:
       gst_caps_replace (&self->preview_caps,
           (GstCaps *) gst_value_get_caps (value));
-      if (self->preview_pipeline) {
-        GST_DEBUG_OBJECT (self,
-            "Setting preview pipeline caps %" GST_PTR_FORMAT,
-            self->preview_caps);
-        gst_camerabin_preview_set_caps (self->preview_pipeline,
-            (GstCaps *) gst_value_get_caps (value));
-      }
+      gst_base_camera_src_setup_preview (self,
+          (GstCaps *) gst_value_get_caps (value));
       break;
     case PROP_PREVIEW_FILTER:
       if (self->preview_filter)
diff --git a/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.h b/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.h
index 4ff5e8842..ef9ae9e87 100644
--- a/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.h
+++ b/gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.h
@@ -109,6 +109,10 @@ struct _GstBaseCameraSrcClass
   gboolean    (*set_mode)            (GstBaseCameraSrc *self,
                                       GstCameraBinMode mode);
 
+  /* set preview caps */
+  gboolean    (*set_preview)         (GstBaseCameraSrc *self,
+                                      GstCaps *preview_caps);
+
   /* */
   GstCaps *   (*get_allowed_input_caps) (GstBaseCameraSrc * self);
 
@@ -130,6 +134,7 @@ GstColorBalance * gst_base_camera_src_get_color_balance (GstBaseCameraSrc *self)
 
 gboolean gst_base_camera_src_set_mode (GstBaseCameraSrc *self, GstCameraBinMode mode);
 void gst_base_camera_src_setup_zoom (GstBaseCameraSrc * self);
+void gst_base_camera_src_setup_preview (GstBaseCameraSrc * self, GstCaps * preview_caps);
 GstCaps * gst_base_camera_src_get_allowed_input_caps (GstBaseCameraSrc * self);
 void gst_base_camera_src_finish_capture (GstBaseCameraSrc *self);