Masks or masking is the ability to show the content of one picture within the confines of another. Imagine you have a large photo and you want to take a portion of that photo and put it in a nice wooden frame that you bought. You have two objects, the photo and the frame. If you place the frame over the area of the photo that you want and then proceed to cut the area of the photo that you need to put in the frame, then what you are doing is masking. Digitally, the concept is the same. To the left and below is a photo of my daughter. There are typically two parts to a mask, the background and frame. The frame consists of the border which in this case would be the blue ellipse surrounding her face.
In Expression Design, we don't have menu items that specifically read "Mask", but a masking effect can be achieved with relative ease. Here's how:
1. Open the .design file that contains your custom shapes and also open the file that contains the photo you want to mask. You should have two tabs showing at the top, one for your shapes and one for your photo.
2. Select the document containing your shapes. Select your shapes with the Selection arrow (the dark arrow at the top right of the toolbox). Hit CTRL+C to copy the shapes to the clipboard.
3. Now switch over to the photograph document and hit CTRL+F or Edit, Paste in Front from the menu. You should now see your shapes on the photograph page and your shapes are selected. Both the shapes and the photo should be in the same layer.
4. Hold down the SHIFT key and click anywhere on the photo so that the shapes and the photo are selected.
5. From the Object menu at the top, click Clipping Path, then Make with Top Path.
What we wind up with is shown to the right.