The rulers displayed in the document windows of Atlantis can be used to change the numeric characteristics of the document components such as page margins, paragraph indents, tab stop positions, etc.
For instance, you can capture the right indent box on the horizontal ruler with the mouse, and drag it to change the right indent of the current selection of paragraphs:
As you drag the box with the mouse, new values are suggested for the corresponding right indent. In the above example, the value of the original right indent is 0. If we drag the indent box to the left, the next possible value of the right indent will be 0.06", then 0.13", 0.19", and so on:
These are so-called "discrete" values. In most cases, such discrete values will be OK. But sometimes you might want to use more precise values. In such cases, you only need to hold the Alt key pressed down as you drag the indent box along the ruler: you'll be able to choose from a continuous range of values, such as 0.01", 0.02", 0.03", 0.04", 0.05", in addition to 0.06" - offered by default with the first method.
Things work in the same way whenever you use the ruler to adjust other indent types, or page margins, or column spacing, etc:
Drag the mouse to get new discrete values. Hold the Alt key down and drag to get a continuous range of possible values.