Added the zfill, from_rgb, to_hex, lower, upper methods (v4.0.21)

[simon-ritchie]

Since version 4.0.21, the ap.String's zfill , lower, and upper methods have been added:

import apysc as ap
...

string: ap.String = ap.String(value="1")
string = string.zfill(width=3)
ap.assert_equal(string, "001")

...
string: ap.String = ap.String("AbC1_")
string = string.lower()
ap.assert_equal(string, "abc1_")

...
string: ap.String = ap.String("AbC1_")
string = string.lower()
ap.assert_equal(string, "abc1_")

The ap.Color's from_rgb class method and ap.Int or ao.Number's to_hex method have been added in the same version:

import apysc as ap
...
cyan_color: ap.Color = ap.Color.from_rgb(red=0, green=128, blue=255)
cyan_rectangle: ap.Rectangle = ap.Rectangle(
    x=250,
    y=50,
    width=50,
    height=50,
    fill_color=cyan_color,
)

import apysc as ap
...
int_value: ap.Int = ap.Int(28)
hex_str: ap.String = int_value.to_hex()
ap.assert_equal(hex_str, "1c")

For more details, please see the following documents:

• String class zfill method
• Color class from_rgb class method
• Int and Number classes to_hex method
• String class lower method
• String class upper method