The mouse button on a tv_tool sets the mouse buttons.(The mouse is also set when the mouse button is pressed in another tool). There are three options ;-
left down ipos: the Tv image pixel (integer) position. middle down pos2D: the physical image position (sub pixel) with respect to image coordinates (takes account of scale). right down pos3D: the image position of the underlying physical image with respect to 3D co-ordinates of the camera located at the centre of the image.
left down grey: the grey level of the physical image. left down grey: the pixel value of the tv image.All diagnostics are written to the main tool.