1.3   The zoom function

One of the functions in the View menu is Zoom. You can access the zoom dialogue window in several ways:

From the menu bar:
  - either click on View, then Zoom on the drop down menu,
  - or hold down the [ALT] key and type V, then type [Z]. ( In short [ALT+V] > [Z] ).
Mouse shortcut:
  Right-click on the image (depress the right mouse button) and select Zoom.

The zoom dialog

As you see the zoom dialogue window has two main options

1. Set the zoom % by typing the zoom level you want (range 10 to 2000; 100 is full size, 50 is half size). Then click OK or press 'Enter'.
2. Zoom to fit the image window:
   - either keep the height to width aspect ratio; select 'Preserve shape',
   - or fit the image to the Bilko image window; select 'Don't care'(about the shape).

Expriment with the zoom option:

1. Try a 10% zoom, and see how the image shrinks to a thumbnail.
2. Click on the centre of the thumbnail image to position your cursor there. Then try a 2000% zoom and observe how this makes you able to see each pixel clearly as a grey square.
3. Try each the two versions of 'Zoom to fit' in turn, and experiment with resizing the image window, to see what happens.

Question 1:
When the zoomed image becomes larger than the window, what do you think determines which part of the image is displayed?

Note: You may already have noticed that the zoom function in Bilko is very similar to that in software such as Word and Excel. In Bilko, as in many other Windows applications, a zoom of 200% means enlarging the display to twice the original size, a zoom of 2000% enlarges it to 20 times the original size.

Zoom information on the status bar

By looking at the Bilko status bar, you can get information about the zoom level without having to open the dialogue window (see figure (1K)) This is particularly useful when you are using the 'zoom to fit' option.

To explore this you might try the following activity::

1. Resize the window, and choose 'Preserve shape' option, making a note of the zoom % from the status bar.
2. Increase the height of the image window, by dragging on the bottom edge with your mouse. Watch what happens, both to the image display and the zoom % on the status bar.
3. Change the zoom setting to 'Don't care', and again make a note of what happens to the image display and the zoom % on the status bar.
4. Increase the width of the window and watch what happens to the image and the zoom % on the status bar.

Question 2:
How is the zoom % on the statusbar calculated - from the image width or from the image height?