Would this help
mouse control

class DrawBoxPointDJ

def onLButtonDown( flag,x, y,dj_view )
Sketchup.active_model.start_operation "onLButtonDown",true,true,true
dj_xdown = x;dj_ydown = y;dj_view="drawBoxPoint_dj";dj_point=(Sketchup.active_model.active_view.inputpoint x,y).position

puts dj_point

.
.
.
.

end
end

Also

BMVBv1-Script

by T. Marek

Sections: Animation - Camera ; Materials - Rendering

Draws a face that covers precisely current view. Created face can be used for B&W image with alpha transparency taken from the same camera possition. Face can be semitransparent and have some openings.