Text styles
rgb r g b raises Invalid_argument if one of r, g or b is not in the range 0..255.
rgb r g b
Invalid_argument
r
g
b
0..255
Type of text styles.
Style with all fields set to None.
None
merge s1 s2 is s2 with all undefined fields set to ones of s1.
merge s1 s2
s2
s1
equal s1 s2 returns true iff s1 and s2 are equal after having replaced all None fields by Some false or Some Default.
equal s1 s2
true
Some false
Some Default