Pan and Zoom Increments

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Each time you make a change to the pan, zoom and rotation using the Tool Bar buttons or key commands, the image changes by a certain predefined "increment." The size of the increment is important. For example, when your are zoomed-out on a big cave, you usually want to use large increments so you can rapidly zoom-in on a specific part of the cave. After you have zoomed-in, you usually want to use smaller increments so you don’t overshoot the target and you can get the precise view of the cave you want.


Action Multiplier. As a result, the Viewer allows you to select the amount of pan, zoom and rotation that occurs with each keystroke or mouse click. This “Increment” or "Action Multiplier" selects the number of units each action accomplishes.


Setting the Multiplier. There are several ways to set the Action Multiplier. The easiest way is to use the "Multiplier" drop-down box on the tool bar. By click-on the arrow button next to the box, a list of all the increments will appear. This makes it easy to select the increment with a single mouse click. You can also set the Multiplier by clicking-on the “Change Multiplier” button on the tool bar or by typing the “M” key on the keyboard. This will cause the multiplier to change to the next value in the sequence. In this way, you can cycle through all possible increments. Finally, you can also set the multiplier by selecting "Preferences|Settings" from the menu bar.


Selecting Multipliers. Large multipliers are useful when you are zoomed out and need move quickly. Small multipliers are most useful when you have zoomed-in and need to make fine adjustments. The Action Multiplier can be set to .1, 1, 3, 5, 10 and 30. (These are logarithmic values, which give a broad range of multipliers.)


Multiplier Units. For pans and zooms, the multiplier units are in pixels. For rotation, the units are degrees. For example, if the multiplier is ten, pans and zooms will move ten pixels for each keystroke or mouse click. For rotations, each keystroke or mouse click will rotate ten degrees.