Function fromName

Create a color from its name, as defined by the following schemes:

• A string of the form x:A:R:G:B, where x is any text not containing a colon, and ARGB are integers between 0 and 255.
• A string of the form x:name, where x is as above and name is lowercased and re-evaluated by this function.
• A hex code of the form #RRGGBB. Alpha is 255.
• A hex code of the form AARRGGBB, with no hash mark.
• The name of one of the HTML Known Colors in lowercase (https://www.w3schools.com/colors/colors_names.asp)
• Otherwise, white.