Positive numbers indicate downward and rightward direction. Thus in the example above, the top left corner of the clipping rectangle will inset rightward 20 pixels and downward 30 pixels from the top left corner of the layer . The bottom right corner of the clipping rectangle will be 180 pixels rightward and 300 pixels downward from the upper left corner of the layer . This clipping rectangle is smaller than the layer and lies inside it. If you specify a background color for the layer, the color will flood the entire clipping area .
Negative numbers indicate leftward and upward direction.
Notice, however, that the space occupied by the display is now 40 pixels wider and 40 pixels higher than the layer itself . You must plan your displays accordingly. A clipping rectangle is relative to the top left corner of its layer. So you need not change the clipping rectangle if you change the position of the layer by changing its TOP or LEFT values. If you change the shape of the layer, however, you will have to change the clipping rectangle.