You can resize the Ruler from the edges with the standard
Drag gesture. On a horizontal ruler you can resize from the left and right sides. For a vertical ruler, you can resize from the top and bottom.
You can also hold the
Option key to do symmetric resizing (ie. sizing from both sides at once). This is a standard OSX behavior for all windows.
Although mouse-based resizing works great, real fine-tuning can be done with the keyboard. Use the
- keys to increase and decrease the size of the ruler by 1pt. Hold the
Shift key to size in 10pts.
The ruler can be toggled between horizontal and vertical orientations with the
You can move the ruler with a
Drag gesture anywhere on the window. As you move between monitors, the tick marks will auto-adjust for retina and non-retina displays.
You can also use the
↓ keys to move the ruler by 1pt in any of the 4 directions. Hold the
Shift key to move by 10pts.
As you move your mouse along the ruler, you will see the relative position within the ruler. The relative position is shown next to the ruler size.
This is useful to get a rough measure along a side, without having to resize the ruler.