Subsections
The functions Zoom and New View are for doing precision,
pixel-scale work on an image. This section describes these
particularly useful functions.
1.8.1 Zoom
Figure
1.16
Figure 1.16:
Using Zoom
 |
illustrates the use of
Zoom. The
Zoom
function, enabled by clicking on the magnifying glass icon in the
Toolbox, has two modes of operation. The first mode is used by
clicking and dragging in the image window to frame a part of the
image. When the mouse button is released, the delineated region is
zoomed. Figure
1.16(a) shows a zoom selection area
created with the mouse, and Figure
1.16(b) shows how
this region is zoomed to fill the entire image window. This is a
convenient way to zoom into a specific region of your image.
The second mode of operation for the Zoom tool is accessed by
simply clicking or Shift-clicking in the image window. Each click
zooms in a step and each Shift-click zooms out a step. The image
window can also be zoomed in or out with keyboard shortcuts. Zooming
in is performed by typing = in the image
window, and zooming out is performed by
typing - (that is, the minus key). Notice that the = is
on the same key as the +, which should remind you that it adds
or increases zoom. By contrast, the - key subtracts or
decreases zoom. An advantage of the keyboard shortcuts is that they
function without having to first click on the Zoom icon in the
Toolbox.
The function Shrink Wrap, found in
the Image:View menu, can be used to resize the window to
encompass the entire image, but only within the limits of your
monitor's screen. Shrink Wrap can also be invoked by typing
C-e in the image window.
Whenever a part of a zoomed image cannot be seen in the image window,
the image panner, described in Section
1.1.2, can be
used to pan to a desired image area. There are also three other
possibilities for panning in a zoomed image. There are the
window's scroll bars, however, these probably aren't the most
convenient method. The second choice is to middle-click and drag in
the image window. This can work reasonably well if the image needs to
be adjusted only incrementally. If it is necessary to pan back and
forth between many different regions of a zoomed image, the Navigation Window is probably the most convenient.
The use of the Navigation Window, found in the Image:View
menu, is shown in Figure
1.17.
Figure
1.17(a)
Figure 1.17:
Using Zoom with the Navigation Window
 |
illustrates an image zoomed to 200%, and
Figure
1.17(b) shows the
Navigation Window.
This dialog allows the image to be panned in the image window by
clicking and dragging on the view rectangle. You can also use the
Navigation Window to control the degree of zoom by clicking on
the
+ and - buttons.
