Get ANSI Code with Euclidean Distant

We all love cli and colorful console for our terminal.

Initially, I was customizing my zsh shell prompt for different color combination. And I learnt about ANSI code in more details.

ANSI/RGB

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There are 3 types of ANSI color codes. And here’s the breakdown:

1. 16-color Palette:

   • ANSI codes 30-37 and 90-97 represent a 16-color palette.
   • Each color has a specific RGB value.

2. 256-color Palette:

   • ANSI codes 38;5;0-255 represent a 256-color palette.
   • This includes the 16-color palette, 216 colors formed by combining 6 levels of red, green, and blue, and 24 greyscale colors.
   • Total 256 possible colors (16x Basic + 216x RGB + 24x Grayscale).
   • print(f'\033[38;5;{0~255}m256-color ANSI code\033[0m')

3. Truecolor ANSI code

   • ANSI codes 38;2;R;G;B represents true color (R,G,B are int from 0 to 255).
   • HTML Hex code color is represented in truecolor, such as #a1e335.
   • Total of 16,777,216 possible colors (256x256x256).
   • print(f'\033[38;2;{0~255};{0~255};{0~255}m16M-color ANSI code\033[0m')

Euclidean Distant

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In math, Euclidean distance is the method to calculate the distant between two points. The 2 points can be one-dimension, two-dimension or more. In this case, we are calculating the RGB which is three-dimension.

There is no direct 1x1 mapping between all ANSI codes and true RGB colors. But there is direct mapping between RGB and true RGB.

Thus, our goal is to find the approximate ANSI code by go with the closest RGB code.

Pseudocode

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Here’s the pseudocode:

1. Generate a dict to store mapping between ANSI code (256-color palette) and corresponding RGB values.
2. Based on the input value (hex_code), calculate the closest distant (using Euclidean).
3. Print the output with sample color/code.

Finally, I put everything in Python script called find_closest_ansi.py. It is at the following repo at GitHub.