Units
gPage uses a coordinate system where each point maps to a screen pixel when the zoom is set to normal (100%). You may define the real size of the points (their printed size) and the size they represent to scale.
The menu item Page+Units... pops up a dialog box to set units preferences.
Resolution
Sets the real size of a point when printed. This value is given in dots per inch (DPI). You may enter a value or let gPage compute this field by choosing one of the preset values.
Scale
Sets the scale size of a pixel. This value is used to compute the sizes displayed on screen and those entered at the keyboard. You may enter a value or let gPage compute this field by choosing one of the preset values.
Decimals
Sets the number of digits shown after decimal point. You may enter a value or let gPage set an appropriate one by choosing one of the preset values.
Units Name
gPage does not use this name, but it is shown on the status bar to remind which units are used in the document. A suitable name is given when you choose one of the preset values, but you can change it according to your needs.
Format
With this option you change the way values appear on screen and in the document. Decimals are appropriate for metric scales and decimal inches, while non-metric scales may show as inches/fraction of an inch, or feet/inches/fraction of an inch. This option is set to a suitable value when you choose one of the preset values, but you can change it afterwards.
Keep Original Paper Size
With this option on, the units can be changed without changing the overall size of the drawing. Useful if the paper size is already set.
Adjust Grid and Snap
With this option on, a suitable value will be calculated for the grid and the snap when you select one of the preset values. If off, actual values will not be changed.
Preset Values
Unless you fully understand what you are doing (or are willing to make some tests), it is more convenient to choose a predefined value from the list. This will compute all necessary values in the dialog box. You may change any value afterward to suit your needs.
Result to Scale
Each time a value is changed in the dialog box, gPage computes the final result so you may check if this is what you expected. This one is the size of the whole drawing to scale.
Result on Paper
Each time a value is changed in the dialog box, gPage computes the final result so you may check if this is what you expected. This one is the size of the whole drawing on paper. The units are given in inches or centimeters depending on the selection made through the menu Preferences+Units System.