Define here the maximum and step parameters 
controlling the ruler (in the tools menu).
Rotate
Max sets the range of angle values accepted by the ruler, 
to rotate objects. Clicking on the ruler extreme left, the 
object is rotated by 
-Max. Clicking on the ruler 
extreme right, the object is rotated by 
Max. 
Max must be positive.
The rotation angle applied to the object, when clicking on the
ruler, increases from the extreme left to the extreme right 
(from 
-Max to 
+Max), in a step by step way. 
The width of each step, starting from the center to the extremes, 
is defined by 
Step.
For example, when 
Step is set to 
Max,
only two angles are recognized: 
-Max on the left
(negative) side and 
+Max on the right (positive)
side of the ruler. When 
Step is 0, the angle
changes continuously from one extreme to the other.
Step cannot exceed 
Max, otherwise the extreme 
values would never be reached (the central value is always 0).
Move
Max sets the range of length values accepted by the ruler,
to move objects. Clicking on the ruler extreme left, the
object is moved by 
-Max. Clicking on the ruler
extreme right, the object is moved by 
Max.
Max must be positive.
The translation length applied to the object, when clicking on 
the ruler, increases from the extreme left to the extreme right
(from 
-Max to 
+Max), in a step by step way.
The width of each step, starting from the center to the extremes,
is defined by 
Step.
For example, when 
Step is set to 
Max,
only two lengths are recognized: 
-Max on the left
(negative) side and 
+Max on the right (positive)
side of the ruler. When 
Step is 0, the length
changes continuously from one extreme to the other.
Step cannot exceed 
Max, otherwise the extreme
values would never be reached (the central value is always 0).
Scale
Max sets the range of factor values accepted by the ruler,
to scale objects. Clicking on the ruler extreme left, the object 
is scaled by 
1 / Max. Clicking on the ruler extreme right, 
the object is scaled by 
Max. 
Max must be larger than 1.
For example, when 
Step is set to 
Max - 1,
only two factors are recognized: 
1 / Max on the left
side and 
Max on the right side of the ruler. When
Step is 0, the factor changes continuously
from one extreme to the other.
Step cannot exceed 
Max - 1, otherwise the extreme 
values would never be reached (the central value is always 1).