Output format

[NateBaldwinDesign]

Description

This issue closes #75

Added output option to generateContrastColors and generateAdaptiveTheme functions.

The output option refers to the desired color format that is returned by the function. Currently (and now by default), the output format is "HEX". However, now the following additional formats can be chosen by the user:

Output option	Sample value
'HEX' (default)	#RRGGBB
'RGB'	rgb(255, 255, 255)
'HSL'	hsl(360deg, 0%, 100%)
'HSV'	hsv(360deg, 0%, 100%)
'HSLuv'	hsluv(360, 0, 100)
'LAB'	lab(100%, 0, 0)
'LCH'	lch(100%, 0, 360deg)
'CAM02'	jab(100%, 0, 0)
'CAM02p'	jch(100%, 0, 360deg)

Output formats conform to the W3C CSS Color Module Level 4 spec for the supported options (rgb, hex, lab, lch, hsl).

The formatting is performed by the fixColorValue(color, format, object) function.

• color is the input color, of any format
• format is the desired output of the color
• object is a boolean option to either return a string or object. The object format conforms to d3 module formatting for these colors (sans the opacity object), and the string format conforms to W3C spec as mentioned above.

Within this function, another helper function filters through any NaN values that d3 returns for a color and replaces them with 0. While this may not be technically correct in the color science realm, the output and consumption of these colors using a 0 value where a NaN is defined is inconsequential. Primary example being the definition of grays in LCh space. While LCh would assign NaN to the chroma and hue, a value of 0 would produce the same color, as any value in place of NaN would produce the same output when clamped to RGB.

Motivation

This enhancement will enable teams that want to manipulate colors beyond Leonardo, or leverage supported color specs more directly. This removes the barrier for users to create their own color transformations as well.

This PR includes thorough testing for the new fixColorValue() function.

Additional tests to verify accuracy of output option are included in generateContrastColors and generateAdaptiveTheme test suites.

Screenshots

To-do list

• I have read the CONTRIBUTING document.

• This pull request is ready to merge.