view-start

Get the location at which the visible portion of the canvas starts, based on the current value of the horizontal and vertical scrollbars. Combined with get-client-size, the application can use this function to efficiently redraw only the visible portion of the canvas. The values are in logical scroll units, not pixels, so to convert to pixels you will have to multiply by the number of pixels per scroll increment.

• (send a-wx:canvas view-start x y) -> void
      x : boxed small integer
      y : boxed small integer

  The x box is filled with the horizontal scrollbar value and y is filled with the vertical scrollbar value.