gradient_filled_segment

bubbletea_rs::gradient

Function gradient_filled_segment 

Source 
pub fn gradient_filled_segment(filled_width: usize, ch: char) -> String
Expand description

Creates a gradient-colored text segment for terminal display.

This function generates a string containing a gradient-colored sequence of characters using ANSI escape codes. Each character is colored using linear interpolation between Charm’s default gradient colors, creating a smooth color transition from left to right. This is commonly used for progress bars, loading indicators, and other visual elements in terminal user interfaces.

§Arguments

  • filled_width - The number of characters to include in the gradient segment. If 0, returns an empty string.
  • ch - The character to repeat for each position in the gradient (commonly ‘█’, ‘▓’, etc.)

§Returns

A String containing the gradient-colored characters with embedded ANSI escape sequences. Each character includes both the foreground color code and a reset sequence.

§Performance Notes

This function pre-allocates string capacity and manually constructs ANSI sequences to avoid the overhead of format macros and style library allocations. It’s optimized for repeated use in animation loops and real-time rendering.

§Examples

use bubbletea_rs::gradient::gradient_filled_segment;

// Create a 10-character gradient progress bar
let progress = gradient_filled_segment(10, '█');
println!("{}", progress);

// Create a loading spinner segment
let spinner = gradient_filled_segment(5, '▓');
print!("Loading: {}\r", spinner);

// Empty width returns empty string
let empty = gradient_filled_segment(0, '█');
assert_eq!(empty, "");

§ANSI Escape Sequence Format

Each character in the output follows the pattern: \x1b[38;2;r;g;bm{char}\x1b[0m

Where:

  • \x1b[38;2;r;g;bm sets the foreground color to RGB(r,g,b)
  • {char} is the specified character
  • \x1b[0m resets all formatting

§See Also