b0¶

Set color 0 to actual black.

bd¶

When the palcomp xterm command is used, also emit a colorBD parameter and use color 15.

bg¶

When the palcomp xterm command is used, also emit a -bg parameter and use color 0.

blend=pct,name¶

RGB-blend the current palette with another; performs `output := curpal*(100-pct) + secondpal*pct`. pct should be in the range 0..100.

ct¶

Print the 16-color table.

ct256¶

Print 256-color cubes and tables.

cxl¶

Print a contrast analysis of the palette based on brightness differences.

cxa¶

Print a contrast analysis of the palette based on Myndex Advanced Perceptual Contrast Algorithm (APCA W3). Be aware of the Helmholtz–Kohlrausch effect, where certain highly saturated colors appear brighter than their measured luminance would imply; in other words, a color pair might appear more legible than the computed contrast value indicates.

eq[=b]¶

Equalize (equal-space) the lightness values of the palette's colors. The b parameter (0 <= b <= 100) specifies the mandatory lightness difference from the darkest to 2nd darkest color. In practice, b specifies the lightness value that blue is to be assigned. If b is absent, uses b=1/16.

eval=expr¶

Evaluate an (almost) arbitrary expression for every palette entry. The identifiers r, g and b refer to RGB components of the palette entry. The identifiers l, c and h refer to LCh components of the palette entry. x, y and z refer to temporaries free for use. Known operators are +, -, *, /, ^ (exponentiation), , (comma operator) and =. Grouping with (...) is recognized.

As a shorthand, if expr begins with an opening parenthesis or a one-letter identifier followed by =, the expression can also be used as a command without the need to type eval=.

eval@LIST=expr¶

Evaluate expression for the given colors. LIST shall be a comma-separated list of palette indices or index ranges, e.g. "0,4-7,12".

fg¶

When the palcomp xterm command is used, also emit a -fg parameter and use color 7.

hsltint=h,s,l¶

Map the (LCh) brightnesses onto a color line through the HSL cylinder that goes from black to the chosen color. Parameter ranges are (0 <= h < 360; 0 <= s < 1; 0 <= l <= 1). When using s<=0.5, this produces a black-to-{color} ramp; when using s==1, this produces a black-to-{color}-to-white ramp.

hsltint produces a somewhat more contrasty result than manipulating hue (h) and saturation/chromaticity (c) in LCh. Compare:

• palcomp vgs c=100 h=120 emit
• palcomp vgs hsltint=90,1,0.5 emit

hsltint=#rrggbb[,l]¶

A different syntax for the hsltint operation. First, the RGB value for the tint color is converted to HSL. The so-computed L value can be overridden with the optional ,l suffix. Afterwards, behaves like hsltint=h,s,l.

ild=t¶

Set the white point to be a series D illuminant at color temperature t. (t should be in the range 4000..25000 K). This only has an effect for the "cxa" command. (Commands like hue/lightness modification all use libbabl, which hardcodes D65.) The default white point used by palcomp is ild=6500. Note that D65 is not exactly 6500 K, due to changes of the Planck constant between when Illuminant D was first defined and 2019.

inv16¶

Perform color inversion the way Norton Icon Editor did it.

lch¶

Emit the LCh form of the palette to stdout (no particular formatting).

lchtint=h,s,l¶

lchtint=#rrggbb[,l]¶

Replace the LCh hue and saturation by the base color given in HSL or RGB. The LCh L value is retained as-is.

loadpal=¶

Load RGB palette from a file. xfce4-terminal *.theme files and termux *.properties files are understood.

loadreg=name¶

Set the working palette ("0") to the contents of the named palette.

loeq[=b[,g]]¶

Equalize (equal-space) the lightness values of the palette's low-intensity colors plus darkgray. The b parameter (0 <= b <= g <= 100) specifies the mandatory lightness difference from the darkest to 2nd darkest color. In practice, b specifies the lightness value that blue is to be assigned. The g parameter (b <= g <= 100) specifies the lightness that the brightest color of the low-intensity section is to use (in practice, the lightness for grey). If g is absent, defaults to g=88.88; this is so that gray is still a little less intense than white. If b is absent, uses b=11.11.

savereg=name¶

Save the current working palette ("0") to a new name.

syncfromlch¶

syncfromrgb¶

Explicitly synchronize palette representations. This can be used to experiment with value clippings (e.g. `palcomp vgs 'l=l*2' syncfromrgb 'l=l/2'`; the result of l*2 normally cannot be represented in RGB and causes clipping).

vga¶

Loads the standard VGA palette.

vgs¶

Loads a full-saturated VGA palette.

win¶

Loads the standard Windows palette.

xfce¶

Emit the palette as a line for an xfce4-terminal theme file.

xterm¶

Emit the palette as xterm command line options. Use e.g. `xterm $(palcomp vga h=120 xterm)` to utilize.