| iTool User's Guide: Manipulating the Display |

## Zooming

Two types of zooming are available in all iTools:

- Canvas Zoom changes the magnification of the entire display canvas (everything in the iTool window). If the display canvas is larger than the iTool window, scroll bars appear.

- View Zoom changes the magnification applied to the selected view. If the size of the view is larger than the visible portion of the view (that is, if the view zoom is greater than 100%), the view pan manipulator becomes active, allowing you to move different portions of the view into the visible area.

### Canvas Zoom

Canvas Zoom increases or decreases magnification of the entire iTool window without moving the observer's "eye."

To zoom in or out with Canvas Zoom:

1. Select Window Canvas Zoom and select a percentage from the list.

- To increase magnification, choose a percentage greater than 100%.

- To decrease magnification, choose a percentage less than 100%.

2. Select 100% to return to the default magnification.

### View Zoom

View Zoom increases or decreases magnification of items in the currently selected view in an iTool window. This is similar to moving the observer's "eye" closer to or farther away from the objects in the view. You can change the view zoom using the view zoom button or by using the view zoom pull-down menu.

To use the view zoom button:

1. Click Zoom on the toolbar to enter Zoom mode.

2. Position the mouse pointer on the viewplane. The pointer changes to a zoom pointer .

3. Do either of the following:

- Drag the zoom pointer toward the top of the iTool window to enlarge the display

- Drag the zoom pointer toward the bottom of the iTool window to make the display smaller

4. Click on the arrow Select button to leave Zoom mode and return to Select mode. The mouse pointer changes to an arrow pointer. In Select mode, dragging the arrow pointer positions the zoomed image.

The view zoom combobox is located just to the right of the view zoom manipulator button on the toolbar and always reports the zoom factor of the currently selected view. You can also use this combobox to set a requested zoom factor for the currently selected view by simply using the pull-down menu to select a value.

IDL Online Help (March 01, 2006)