"Offset" allows you to shift the content of the active layer. Anything that gets shifted outside the edges of the layer is cropped away. Choosing this menu entry brings up a dialog that allows you to specify how the shift should be performed. You can set the distance to shift the layer in the X and Y directions, measuring from the upper left corner, with positive numbers representing movement to the right (X) or downward (Y). The default units are pixels, but you can use the Units menu in the Offset area to change this if you like: units of "%" are sometimes useful. Pressing the button labeled "Offset by x/2, y/2" will cause the layer contents to be shifted exactly half the width and height of the layer.

10.52.2.  The "Offset" dialog

Figure 10.81.  The "Offset" dialog

Offset

X;Y

With these both options, you can set how long the content of the active layer offset will be in the respective directions. You have two input boxes with arrow heads to enter offset in pixels. You can select another unit of measurement in the next drop-down list.

Offset by (x/2),(y/2)

Ought to this button, you can set X and Y offset by half the width and height of the image automatically.

Edge Behavior

There are three possible ways to treat the areas left empty by the shift, specified by "Edge Behavior":

• Wrap around: This option causes the empty space to be filled with the parts of the layer that are shifted outside the edges.

• Fill with background color: This option causes the empty space to be filled with the Background color shown in the Color Area of the Toolbox.

• Make transparent: This option causes the empty area to be made transparent. If the layer lacks an alpha channel, "Make transparent" will not be available.