3. Colours and styles

Every element takes three more keywords: <element>_color_fg (the colour of the characters), <element>_color_bg (the colour behind them) and <element>_style (bold, italics, underline, ...). With the full block █ for both parts and two colours, the bar becomes solid:

call bar%initialize(prefix_string='march ', prefix_color_fg='cyan', prefix_style='bold_on',             &
                    bracket_left_string='[', bracket_right_string=']',                                  &
                    filled_char_string='█', filled_char_color_fg='green',                               &
                    empty_char_string='█', empty_char_color_fg='black_intense',                         &
                    suffix_string=' time steps', suffix_color_fg='yellow', suffix_style='italics_on', &
                    width=40, max_value=real(steps, R8P))

While running:

$ march
march [████████████████████████████████████████] time steps

• Colours and styles are names: red, green_intense, bold_on, ... in any case. There are 17 colours, the same for the foreground and the background, and 16 styles: the full list is in Colours and styles. A colour may also be a 24-bit #rrggbb, the same on every terminal palette.
• A name that is not in the list stops the program in initialize, with a message that names it: a typo cannot go unnoticed.
• Each element takes one style.
• A background colour fills the cell behind the characters: filled_char_string=' ', filled_char_color_bg='green' makes a solid bar too. The outputs of this documentation cannot show background colours, so the examples use foreground ones.

Colours are ANSI escape sequences, written with the bar: the terminal must understand them (every modern terminal does). Sent to a file, they are written into the file as they are.

What you learned

The _color_fg, _color_bg and _style keywords of every element; a solid bar. Reference: Colours and styles.

Next: 4. What the bar reports.