6.20. Color Functions

bar(x, width) → varchar

Renders a single bar in an ANSI bar chart using a defaultlowcolor of red and a high_color of green. For example,if x of 25% and width of 40 are passed to this function. A10-character red bar will be drawn followed by 30 spaces to createa bar of 40 characters.

bar(_x, width, low_color, high_color) → varchar

Renders a single line in an ANSI bar chart of the specifiedwidth. The parameter x is a double value between [0,1].Values of x that fall outside the range [0,1] will betruncated to either a 0 or a 1 value. The lowcolor andhigh_color capture the color to use for either end ofthe horizontal bar chart. For example, if x is 0.5, widthis 80, low_color is 0xFF0000, and high_color is 0x00FF00this function will return a 40 character bar that varies from red(0xFF0000) and yellow (0xFFFF00) and the remainder of the 80character bar will be padded with spaces.

color(_string) → color

Returns a color capturing a decoded RGB value from a 4-characterstring of the format “#000”. The input string should be varcharcontaining a CSS-style short rgb string or one of black,red, green, yellow, blue, magenta, cyan,white.

color(x, low, high, low_color, high_color) → color

Returns a color interpolated between lowcolor andhigh_color using the double parameters x, low, andhigh to calculate a fraction which is then passed to thecolor(fraction, low_color, high_color) function shown below.If x falls outside the range defined by low and highit’s value will be truncated to fit within this range.

color(_x, low_color, high_color) → color

Returns a color interpolated between lowcolor andhigh_color according to the double argument x between 0and 1.0. The parameter x is a double value between [0,1].Values of x that fall outside the range [0,1] will betruncated to either a 0 or a 1 value.

render(_x, color) → varchar

Renders value x using the specific color using ANSIcolor codes. x can be either a double, bigint, or varchar.

render(b) → varchar

Accepts boolean value b and renders a green true or a redfalse using ANSI color codes.

rgb(red, green, blue) → color

Returns a color value capturing the RGB value of threecomponent color values supplied as int parameters ranging from 0to 255: red, green, blue.

原文: https://prestodb.io/docs/current/functions/color.html