basecamerasrc: camerabin2: wrappercamerabinsrc: Add read-only max-zoom prop

This is not implemented in any of our real sources to which wrappercamerabinsrc
might connect but this is optional and can be implemented at any time. A
limit on the software zoom level using video{crop,scale} would be arbitrary.

gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.c

@@ -61,6 +61,7 @@ enum
   PROP_0,
   PROP_MODE,
   PROP_ZOOM,
+  PROP_MAX_ZOOM,
   PROP_READY_FOR_CAPTURE,
   PROP_POST_PREVIEW,
   PROP_PREVIEW_CAPS,
@@ -338,6 +339,12 @@ gst_base_camera_src_set_property (GObject * object,
       break;
     case PROP_ZOOM:{
       self->zoom = g_value_get_float (value);
+      /* limit to max-zoom */
+      if (self->zoom > self->max_zoom) {
+        GST_DEBUG_OBJECT (self, "Clipping zoom %f to max-zoom %f", self->zoom,
+            self->max_zoom);
+        self->zoom = self->max_zoom;
+      }
       /* does not set it if in NULL, the src is not created yet */
       if (GST_STATE (self) != GST_STATE_NULL)
         gst_base_camera_src_setup_zoom (self);
@@ -385,6 +392,9 @@ gst_base_camera_src_get_property (GObject * object,
     case PROP_ZOOM:
       g_value_set_float (value, self->zoom);
       break;
+    case PROP_MAX_ZOOM:
+      g_value_set_float (value, self->max_zoom);
+      break;
     case PROP_POST_PREVIEW:
       g_value_set_boolean (value, self->post_preview);
       break;
@@ -530,9 +540,15 @@ gst_base_camera_src_class_init (GstBaseCameraSrcClass * klass)
 
   g_object_class_install_property (gobject_class, PROP_ZOOM,
       g_param_spec_float ("zoom", "Zoom",
-          "Digital zoom factor (e.g. 1.5 means 1.5x)", MIN_ZOOM, MAX_ZOOM,
+          "Digital zoom factor (e.g. 1.5 means 1.5x)", MIN_ZOOM, G_MAXFLOAT,
           DEFAULT_ZOOM, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  g_object_class_install_property (gobject_class, PROP_MAX_ZOOM,
+      g_param_spec_float ("max-zoom", "Maximum zoom level (note: may change "
+          "depending on resolution/implementation)",
+          "Digital zoom factor (e.g. 1.5 means 1.5x)", MIN_ZOOM, G_MAXFLOAT,
+          MAX_ZOOM, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
   /**
    * GstBaseCameraSrc:post-previews:
    *
@@ -603,6 +619,7 @@ gst_base_camera_src_init (GstBaseCameraSrc * self,
   self->width = DEFAULT_WIDTH;
   self->height = DEFAULT_HEIGHT;
   self->zoom = DEFAULT_ZOOM;
+  self->max_zoom = MAX_ZOOM;
   self->mode = MODE_IMAGE;
 
   self->capturing = FALSE;

gst-libs/gst/basecamerabinsrc/gstbasecamerasrc.h

@@ -78,8 +78,8 @@ struct _GstBaseCameraSrc
   gint width;
   gint height;
 
-  /* The digital zoom (from 100% to 1000%) */
   gfloat zoom;
+  gfloat max_zoom;
 
   gpointer _gst_reserved[GST_PADDING_LARGE];
 };

gst/camerabin2/gstcamerabin2.c

@@ -109,6 +109,7 @@ enum
   PROP_AUDIO_CAPTURE_SUPPORTED_CAPS,
   PROP_AUDIO_CAPTURE_CAPS,
   PROP_ZOOM,
+  PROP_MAX_ZOOM,
   PROP_IMAGE_CAPTURE_ENCODER,
   PROP_IMAGE_CAPTURE_MUXER,
   PROP_IDLE
@@ -571,6 +572,12 @@ gst_camera_bin_class_init (GstCameraBinClass * klass)
           "Digital zoom factor (e.g. 1.5 means 1.5x)", MIN_ZOOM, MAX_ZOOM,
           DEFAULT_ZOOM, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  g_object_class_install_property (object_class, PROP_MAX_ZOOM,
+      g_param_spec_float ("max-zoom", "Maximum zoom level (note: may change "
+          "depending on resolution/implementation)",
+          "Digital zoom factor (e.g. 1.5 means 1.5x)", MIN_ZOOM, G_MAXFLOAT,
+          MAX_ZOOM, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
   /* TODO
    * Review before stable
    * - We use a profile for video recording properties and here we have
@@ -649,6 +656,7 @@ gst_camera_bin_init (GstCameraBin * camera)
   camera->viewfinderbin = gst_element_factory_make ("viewfinderbin", "vf-bin");
   camera->imagebin = gst_element_factory_make ("imagecapturebin", "imagebin");
   camera->zoom = DEFAULT_ZOOM;
+  camera->max_zoom = MAX_ZOOM;
 
   /* capsfilters are created here as we proxy their caps properties and
    * this way we avoid having to store the caps while on NULL state to 
@@ -901,6 +909,17 @@ videosink_event_probe (GstPad * pad, GstEvent * evt, gpointer data)
   return TRUE;
 }
 
+static void
+gst_camera_bin_src_notify_max_zoom_cb (GObject * self, GParamSpec * pspec,
+    gpointer user_data)
+{
+  GstCameraBin *camera = (GstCameraBin *) user_data;
+
+  g_object_get (self, "max-zoom", &camera->max_zoom, NULL);
+  GST_DEBUG_OBJECT (camera, "Max zoom updated to %f", camera->max_zoom);
+  g_object_notify (G_OBJECT (camera), "max-zoom");
+}
+
 /**
  * gst_camera_bin_create_elements:
  * @param camera: the #GstCameraBin
@@ -1066,6 +1085,8 @@ gst_camera_bin_create_elements (GstCameraBin * camera)
           camera->preview_filter, NULL);
     }
     g_object_set (camera->src, "zoom", camera->zoom, NULL);
+    g_signal_connect (G_OBJECT (camera->src), "notify::max-zoom",
+        (GCallback) gst_camera_bin_src_notify_max_zoom_cb, camera);
   }
   if (new_src) {
     gst_bin_add (GST_BIN_CAST (camera), gst_object_ref (camera->src));
@@ -1397,6 +1418,12 @@ gst_camera_bin_set_property (GObject * object, guint prop_id,
       break;
     case PROP_ZOOM:
       camera->zoom = g_value_get_float (value);
+      /* limit to max-zoom */
+      if (camera->zoom > camera->max_zoom) {
+        GST_DEBUG_OBJECT (camera, "Clipping zoom %f to max-zoom %f",
+            camera->zoom, camera->max_zoom);
+        camera->zoom = camera->max_zoom;
+      }
       if (camera->src)
         g_object_set (camera->src, "zoom", camera->zoom, NULL);
       break;
@@ -1557,6 +1584,9 @@ gst_camera_bin_get_property (GObject * object, guint prop_id,
     case PROP_ZOOM:
       g_value_set_float (value, camera->zoom);
       break;
+    case PROP_MAX_ZOOM:
+      g_value_set_float (value, camera->max_zoom);
+      break;
     case PROP_IMAGE_CAPTURE_ENCODER:{
       GstElement *enc;
 

gst/camerabin2/gstcamerabin2.h

@@ -87,6 +87,7 @@ struct _GstCameraBin
   GstElement *preview_filter;
   GstEncodingProfile *video_profile;
   gfloat zoom;
+  gfloat max_zoom;
 
   gboolean elements_created;
 };

gst/camerabin2/gstwrappercamerabinsrc.c

@@ -336,6 +336,17 @@ gst_wrapper_camera_bin_src_caps_cb (GObject * gobject, GParamSpec * pspec,
   gst_caps_unref (caps);
 };
 
+static void
+gst_wrapper_camera_bin_src_max_zoom_cb (GObject * self, GParamSpec * pspec,
+    gpointer user_data)
+{
+  GstBaseCameraSrc *bcamsrc = (GstBaseCameraSrc *) user_data;
+
+  g_object_get (self, "max-zoom", &bcamsrc->max_zoom, NULL);
+  g_object_notify (G_OBJECT (bcamsrc), "max-zoom");
+}
+
+
 /**
  * gst_wrapper_camera_bin_src_construct_pipeline:
  * @bcamsrc: camerasrc object
@@ -379,6 +390,13 @@ gst_wrapper_camera_bin_src_construct_pipeline (GstBaseCameraSrc * bcamsrc)
     /* we lost the reference */
     self->app_vid_src = NULL;
 
+    /* we listen for changes to max-zoom in the video src so that
+     * we can proxy them to the basecamerasrc property */
+    if (g_object_class_find_property (G_OBJECT_GET_CLASS (bcamsrc), "max-zoom")) {
+      g_signal_connect (G_OBJECT (self->src_vid_src), "notify::max-zoom",
+          (GCallback) gst_wrapper_camera_bin_src_max_zoom_cb, bcamsrc);
+    }
+
     /* add a buffer probe to the src elemento to drop EOS from READY->NULL */
     {
       GstPad *pad;