Compare GMA

compare.py

from coloraide.gamut import Fit
from coloraide.spaces import RGBish
from coloraide import algebra as alg

class OkLChScale(Fit):
    """
    Gamut mapping by scaling.
    Expected gamut mapping spaces are RGB type spaces.
    For best results, linear light RGB spaces are preferred.
    """

    NAME = "oklch-scale"
    SPACE = "oklch"

    def fit(self, color, space, **kwargs):
        """Scale the color within its gamut but preserve L and h as much as possible."""

        # Requires an RGB-ish space, preferably a linear space.
        if not isinstance(color.CS_MAP[space], RGBish):
            raise ValueError("Scaling only works in an RGBish color space, not {}".format(type(color.CS_MAP[space])))

        # For now, if a non-linear CSS variant is specified, just use the linear form.
        if space in {'srgb', 'display-p3', 'rec2020', 'a98-rgb', 'prophoto-rgb'}:
            space += '-linear'

        orig = color.space()
        mapcolor = color.convert(self.SPACE, norm=False) if orig != self.SPACE else color.clone().normalize(nans=False)
        gamutcolor = color.convert(space, norm=False) if orig != space else color.clone().normalize(nans=False)
        self.scale(gamutcolor)
        gamutcolor.set(
            {
                self.SPACE + '.l': mapcolor['l'],
                self.SPACE + '.h': mapcolor['h']
            }
        )
        self.scale(gamutcolor)
        color.update(gamutcolor)

    def scale(self, color):
        """Scale the RGB color within its gamut."""

        deltas = [c - 0.5 for c in color[:-1]]
        max_distance = max(abs(c) for c in deltas)
        scalingFactor = max_distance / 0.5;
        color[:-1] = [c / scalingFactor + 0.5 for c in deltas]

class ColorScale(Color):
    FIT = 'oklch-scale'

ColorScale.register(OkLChScale())

class ColorRayTrace(Color):
    FIT = 'oklch-raytrace'

class ColorCSS(Color):
    FIT = 'oklch-chroma'

ColorScale.interpolate(['red', 'green'], space='oklch')
ColorRayTrace.interpolate(['red', 'green'], space='oklch')
ColorCSS.interpolate(['red', 'green'], space='oklch')
ColorScale.interpolate(['white', 'blue'], space='oklch')
ColorRayTrace.interpolate(['white', 'blue'], space='oklch')
ColorCSS.interpolate(['white', 'blue'], space='oklch')
ColorScale.interpolate(['oklch(20% 0.8 0)', 'oklch(20% 0.8 360)'], space='oklch', hue='longer')
ColorRayTrace.interpolate(['oklch(20% 0.8 0)', 'oklch(20% 0.8 360)'], space='oklch', hue='longer')
ColorCSS.interpolate(['oklch(20% 0.8 0)', 'oklch(20% 0.8 360)'], space='oklch', hue='longer')