Console color. In Rust, console colors can be used with external crates that have convenient syntax. But this is not always desirable.
With a short function, we can implement our own console coloring logic. This reduces an external dependency in the project, and can lead to further improvements.
Example. With ANSI codes, we can use numbers to indicate colors and whether text is bold. Other display features can be set, but colors and bolding are the most useful.
Info When get_color is called, it adds the prefix syntax for ANSI display information.
Tip For bold text, we must use the "1" code with a trailing semicolon. The console will interpret this to mean bold.
Tip 2 For foreground and background colors, we can write 3 values separated by semicolons.
Finally The program supports red, green, blue, white and black. Further colors could easily be added.
fn get_color_code(name: &str) -> &'static str {
// Limited ANSI color converter.
if name == "red" {
"1"
} else if name == "green" {
"2"
} else if name == "blue" {
"4"
} else if name == "white" {
"7"
} else {
"0"// Black.
}
}
fn get_color(value: &str, bold: bool, color: &str, background: &str) -> String {
// Get string with console color information.
let mut result = String::from("\u{1b}[");
// [1;] means bold.
if bold {
result.push_str("1;");
}
// Handle foreground.
if !color.is_empty() {
result.push_str("38;5;"); // Codes for ANSI foreground.
result.push_str(get_color_code(color));
result.push(';');
}
// Handle background.
if !background.is_empty() {
result.push_str("48;5;"); // Codes for ANSI background.
result.push_str(get_color_code(background));
result.push(';');
}
result.push_str("7m"); // End token.
result.push_str(value);
result.push_str("\u{1b}[0m");
result
}
fn main() {
println!("{}", get_color("TEST", true, "blue", ""));
println!("{}", get_color("TEST", true, "green", ""));
println!("{}", get_color("OK", false, "black", ""));
println!("{}", get_color("OK", false, "", ""));
println!("{}", get_color("TEST", true, "blue", "white"));
println!("{}", get_color("TEST", true, "green", ""));
println!("{}", get_color("OK", false, "black", ""));
println!("{}", get_color("OK", false, "", ""));
println!("{}", get_color("RED", true, "red", ""));
println!("{}", get_color("abc", true, "green", "black"));
}TEST
TEST
OK
OK
TEST
TEST
OK
OK
RED
abc
Benefits. With these functions, we can often reduce a crate dependency and handle colors directly. And with the simple logic, we can make programs follow more unified themes.
Info We can only allow 5 colors, such as the ones in the get_color_code function.
And This can make programs easier to use and consistent. Unusual colors, like fuchsia, can be eliminated.
Summary. Handling colors directly in Rust programs with a custom function can sometimes be desirable. The ANSI codes are understandable once we learn the syntax.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Nov 14, 2023 (edit).
