This command is used to implement scanning on canvases. This command
computes the difference between its xPos and yPos arguments (which are
typically mouse coordinates) and the xPos and yPos arguments to the last
setScanMark command for the widget. It then adjusts the view by gain
times the difference in coordinates, where gain defaults to 1. This
command is typically associated with mouse motion events in the widget,
to produce the effect of dragging the canvas at high speed through its
window.
This command is used to implement scanning on canvases. This command computes the difference between its xPos and yPos arguments (which are typically mouse coordinates) and the xPos and yPos arguments to the last setScanMark command for the widget. It then adjusts the view by gain times the difference in coordinates, where gain defaults to 1. This command is typically associated with mouse motion events in the widget, to produce the effect of dragging the canvas at high speed through its window.