Zooming in and Out

Now, the cropped image occupies only a fraction of the screen. If you look at the title bar of the image window, you will notice that it includes the picture's name and something like "33.3%". The "33.3%" indicates that each pixel on the screen is actually being used to take the place of a 3x3 square of pixels in the actual image. To see the actual details of the image we should enlarge the display so that each screen pixel corresponds to one image pixel.

This can be done using the zoom tool:

• Select the "zoom" tool from the toolbox (it is the last small icon on the right hand side of the tool box and it looks a bit like a magnifying glass).

• Move the mouse into the image window. The cursor will look like the zoom tool icon with a plus sign in the middle.

• Click the mouse once. The display ratio should change from "33.3%" to "66.7%". Click again to get to "100%".

• At this point, the image is large, but the window in which it is displayed is not. Fix this by clicking the window's "zoom box" (the second box from the right end of the title bar).

• Click the mouse within the image a few more times. At about "800%" the individual pixels of the actual image become quite visible. Notice that each time you click, the place where you click is centered in the window when the enlarged image is displayed.

• Hold down the option key. The plus sign in the mouse cursor becomes a minus sign. Click once and notice that you now zoom out instead of zooming in.

• Point the mouse back at the zoom tool icon in the toolbox and double-click. This gets you back to a 1:1 ratio immediately.