In PyChart, the X axis grows to the right, and the Y axis grows up (the same as PostScript, but different from X and Windows).
The length is measured in ``PostScript points'', which coincides with TEX points. Usually, one point is equal to 1/72 inch. Several variables and functions are provided to manipulate lengths.
Chart magnification can be changed by setting
variable theme.scale_factor
.
One can convert a sample data value to a canval coordinate by
calling two methods, x_pos
and y_pos
in area.T
object.