4. The Screen Setup of PhotoLine
This function allows to create guides by typing the position. Therefore, it is very precise way to place a guide.
In addition to numeric values you can use mathematical formulas to define a position (see also section 3.3.7 "Unit Text Fields"). Therefore, the constants "w" and "h" representing the document's width and height are predefined. If you create a vertical guide with a position of "w - 1 cm", the guide will be placed 1 cm from the right edge of the document. They guides position is also stored as formula, so if you are changing the document’s size, the guide will still be placed 1 cm from the document’s right edge. Please note: Your input is saved as formula only if it contains a constant. So in order to define a guide, that has an offset of 1 cm to the left edge, you have to enter "w * 0 + 1 cm".
Guides that are based on formulas are shown as grey text and can be converted to ordinary numbers by using the context menu command Fix of the position field.
Aside from creating and modifying guides, the switch Protected allows to disable editing of guide lines by using the layer tool (see chapter 6.2.1). But even if editing is disabled here, new guides can be created by dragging them out of the ruler.