ansi256

README

ansi256

Small library and tools to calibrate and use an ANSI 256 color terminal.

For pixel emulation, it uses block codes ▒ and ░ to approximate a RGB color using two colors, one foreground and one background.

• cmd/output256 prints all the 256 colors.
• cmd/calibrate256 takes a PNG screenshot as input and generates a new table.
• cmd/genpng256 takes the table and generate a new PNG, to ensure the table looks good.

For calibration, make sure your terminal is not semi-transparent before taking a screenshot.

Documentation

Index

• Variables
• func Raw(foreground bool, c color.NRGBA) string
• type Palette
  • func (p *Palette) ANSI(c color.NRGBA) int
  • func (p *Palette) Block(c color.NRGBA) string

Variables

var Default = &Term256

Default is the default palette to use. It is selected based on the OS.

var Term256 = Palette{}/* 256 elements not displayed */

Term256 is the default look up table for ANSI color codes according to xterm-256.

var TermGnome = Palette{}/* 256 elements not displayed */

TermGnome is the colors as displayed on gnome-terminal.

This table was generated via a screenshot generated by ./cmd/output256 sent to ./cmd/calibrate256 using the Pro theme.

var TermOSX = Palette{}/* 256 elements not displayed */

TermOSX is the colors as displayed on OSX.

This table was generated via a screenshot generated by ./cmd/output256 sent to ./cmd/calibrate256 using the Pro theme.

Functions

func Raw

func Raw(foreground bool, c color.NRGBA) string

Raw returns a string using expanded syntax.

Your terminal may not support it. In that case, fall back to the palette.

Types

type Palette

type Palette [256]color.NRGBA

Palette is the color palette to use. The alpha value is ignored.

func (*Palette) ANSI

func (p *Palette) ANSI(c color.NRGBA) int

ANSI pick the closest term-256 color.

The color is converted to alpha-multiplied RGBA so this is important that alpha is set to 255 for full color. The return value is between 0 and 255.

func (*Palette) Block

func (p *Palette) Block(c color.NRGBA) string

Block returns a character with ANSI code to represent the color as closely as possible using a shaded block and two colors. It is important to clear with "\033[0m" after when done.