Files: gui/ruler.h, gui/ruler.c, gui/vertruler.c, gui/horizruler.c
VRR uses special rulers created to meet all our requirements. In contrast to GTK rulers, our rulers can work with any resolution. According to the zoom, they choose a suitable decimal place as the root decimal place. This value designates proper numbers to be displayed on the rule. It can work with both small and large numbers.
The internal ruler implementation uses Pango drawing functions to display text and draws lines and marks defining the current cursor position.
The rulers support changing the lower and upper limit, moving the lower limit, changing the zoom and resolution and changing the current cursor position.