kwimage.im_color module

class kwimage.im_color.Color(color, alpha=None, space=None)

Bases: NiceRepr

Used for converting a single color between spaces and encodings. This should only be used when handling small numbers of colors(e.g. 1), don’t use this to represent an image.

Parameters

space (str) – colorspace of wrapped color. Assume RGB if not specified and it cannot be inferred

CommandLine

xdoctest -m ~/code/kwimage/kwimage/im_color.py Color

Example

>>> print(Color('g'))
>>> print(Color('orangered'))
>>> print(Color('#AAAAAA').as255())
>>> print(Color([0, 255, 0]))
>>> print(Color([1, 1, 1.]))
>>> print(Color([1, 1, 1]))
>>> print(Color(Color([1, 1, 1])).as255())
>>> print(Color(Color([1., 0, 1, 0])).ashex())
>>> print(Color([1, 1, 1], alpha=255))
>>> print(Color([1, 1, 1], alpha=255, space='lab'))

forimage(image, space='auto')

Return a numeric value for this color that can be used in the given image.

Create a numeric color tuple that agrees with the format of the input image (i.e. float or int, with 3 or 4 channels).

Parameters

• image (ndarray) – image to return color for

• space (str) – colorspace of the input image. Defaults to ‘auto’, which will choose rgb or rgba

Returns

the color value

Return type

Tuple[Number, …]

Example

>>> import kwimage
>>> img_f3 = np.zeros([8, 8, 3], dtype=np.float32)
>>> img_u3 = np.zeros([8, 8, 3], dtype=np.uint8)
>>> img_f4 = np.zeros([8, 8, 4], dtype=np.float32)
>>> img_u4 = np.zeros([8, 8, 4], dtype=np.uint8)
>>> kwimage.Color('red').forimage(img_f3)
(1.0, 0.0, 0.0)
>>> kwimage.Color('red').forimage(img_f4)
(1.0, 0.0, 0.0, 1.0)
>>> kwimage.Color('red').forimage(img_u3)
(255, 0, 0)
>>> kwimage.Color('red').forimage(img_u4)
(255, 0, 0, 255)
>>> kwimage.Color('red', alpha=0.5).forimage(img_f4)
(1.0, 0.0, 0.0, 0.5)
>>> kwimage.Color('red', alpha=0.5).forimage(img_u4)
(255, 0, 0, 127)
>>> kwimage.Color('red').forimage(np.uint8)
(255, 0, 0)

ashex(space=None)

Convert to hex values

Parameters

space (None | str) – if specified convert to this colorspace before returning

Returns

the hex representation

Return type

str

as255(space=None)

Convert to byte values

Parameters

space (None | str) – if specified convert to this colorspace before returning

Returns

The uint8 tuple of color values between 0 and 255.

Return type

Tuple[int, int, int] | Tuple[int, int, int, int]

as01(space=None)

Convert to float values

Parameters

space (None | str) – if specified convert to this colorspace before returning

Returns

The float tuple of color values between 0 and 1

Return type

Tuple[float, float, float] | Tuple[float, float, float, float]

classmethod named_colors()

Returns

names of colors that Color accepts

Return type

List[str]

Example

>>> import kwimage
>>> named_colors = kwimage.Color.named_colors()
>>> color_lut = {name: kwimage.Color(name).as01() for name in named_colors}
>>> # xdoctest: +REQUIRES(module:kwplot)
>>> # xdoctest: +REQUIRES(--show)
>>> import kwplot
>>> kwplot.autompl()
>>> # This is a very big table if we let it be, reduce it
>>> color_lut =dict(list(color_lut.items())[0:10])
>>> canvas = kwplot.make_legend_img(color_lut)
>>> kwplot.imshow(canvas)

classmethod distinct(num, existing=None, space='rgb', legacy='auto', exclude_black=True, exclude_white=True)

Make multiple distinct colors.

The legacy variant is based on a stack overflow post [HowToDistinct], but the modern variant is based on the distinctipy package.

References

HowToDistinct

https://stackoverflow.com/questions/470690/how-to-automatically-generate-n-distinct-colors

Returns

list of distinct float color values

Return type

List[Tuple]

Example

>>> # xdoctest: +REQUIRES(module:matplotlib)
>>> from kwimage.im_color import *  # NOQA
>>> import kwimage
>>> colors1 = kwimage.Color.distinct(5, legacy=False)
>>> colors2 = kwimage.Color.distinct(3, existing=colors1)
>>> # xdoctest: +REQUIRES(module:kwplot)
>>> # xdoctest: +REQUIRES(--show)
>>> from kwimage.im_color import _draw_color_swatch
>>> swatch1 = _draw_color_swatch(colors1, cellshape=9)
>>> swatch2 = _draw_color_swatch(colors1 + colors2, cellshape=9)
>>> import kwplot
>>> kwplot.autompl()
>>> kwplot.imshow(swatch1, pnum=(1, 2, 1), fnum=1)
>>> kwplot.imshow(swatch2, pnum=(1, 2, 2), fnum=1)
>>> kwplot.show_if_requested()

classmethod random(pool='named')

Returns

Color

distance(other, space='lab')

Distance between self an another color

Parameters

• other (Color) – the color to compare

• space (str) – the colorspace to comapre in

Returns

float