view_clipset

#View.ClipSet

##Syntax View.ClipSet (x1, y1, x2, y2 : int)

##Description The View.ClipSet procedure sets the clipping region to the rectangle specified by (x1, y1) - (x2, y2). If a clipping region already exist, it is replaced by the specified rectangle.

A clipping region is the region in which the output will appear. If the rectangle is specified as the clipping region, any drawing done outside the rectangle will not appear.

To set the initial clipping, or remove the old region and replace it with a new one, use View.ClipSet. To set the clipping region back to the entire screen or window, use View.ClipOff.

These commands only work in "graphics" mode.

##Example This program sets the clipping region to five rectangles and then draws random circles. The circles will only appear (or partially appear) in the rectangles.

    const maxx13 : int := maxx div 3
    const maxx23 : int := 2 * maxx div 3
    const maxy13 : int := maxy div 3
    const maxy23 : int := 2 * maxy div 3
    View.ClipSet (0, 0, maxx13, maxy13)
    View.ClipAdd (maxx23, 0, maxx, maxy13)
    View.ClipAdd (maxx13, maxy13, maxx23, maxy23)
    View.ClipAdd (0, maxy23, maxx13, maxy)
    View.ClipAdd (maxx23, maxy23, maxx, maxy)
    
    % Draw the random ovals in the box
    var x, y, clr : int
    loop
        x := Rand.Int (0, maxx)     % Random x
        y := Rand.Int (0, maxy)     % Random y
        clr := Rand.Int (0, maxcolor)   % Random color
        Draw.FillOval (x, y, 30, 30, clr)
    end loop

##Status Exported qualified.

This means that you can only call the function by calling View.ClipSet, not by calling ClipSet.

##See also view_clipadd.html and view_clipoff.html functions.