Support Transparent Colors #40
Description
It would be cool to be able to specify a transparency for the background and text color. This could work using 8-digit hex color codes that include values about the alpha transparency of the color. See https://www.quackit.com/css/color/values/css_hex_color_notation_8_digits.cfm#:~:text=Eight%2Ddigit%20hex%20notation%20consists,alpha%20chanel%20of%20the%20color.&text=The%20RR%20represents%20the%20red,GG%20represents%20the%20green%20component.
PHP has a function called imagecolorallocatealpha() for specifying RGB colors with an alpha value.
Related #21