Open CV widget memory leak

[Alex Wardle <awardle mailing gmail com>]

Hi,

I am trying to create a Gtk Widget using the Python GObject bindings that you can pass an OpenCV image to that will then show it. I have created a class that is inherited from Gtk.Image that is used to show the image. You pass the OpenCV image to this class using the show_frame method, which then updates the Gtk.Image so it shows that image.

I have tested this and it works fine, i.e the image is correctly shown and updated when the show_frame method is called. However every time the image is updated, the memory used increases, until there is not enough memory and the program crashes.

I believe this is due to the memory that image is not being freed correctly. I cannot however work out how to fix this. I have tried unreferencing the gbytes once a new frame is received but this does not help. The memory only builds up when the set_from_pixbuf function is called. If this is commented out the memory usage stays at a constant level.

class OpenCVImageViewer(Gtk.Image):
    def __init__(self):
        Gtk.Image.__init__(self)

    def show_frame(self, frame):
        # Convert to opencv BGR to Gtk RGB
        rgb_image = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)

        # Get details about frame in order to set up pixbuffer
        height = rgb_image.shape[0]
        width = rgb_image.shape[1]
        nChannels = rgb_image.shape[2]

        gbytes = GLib.Bytes.new(rgb_image.tostring())
        pixbuf = GdkPixbuf.Pixbuf.new_from_bytes(gbytes, GdkPixbuf.Colorspace.RGB, False,
                                                 8, width, height, width*nChannels)

        # Add Gtk to main thread loop for thread safety
        GLib.idle_add(self.set_from_pixbuf, pixbuf)
        GLib.idle_add(self.queue_draw)

Does any one know how to free this memory?