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Color map

This page contains classes defined in hakowan.common.colormap module.

ColorMap

A color map is a function that linearly interpolate a set of color samples.

Source code in hakowan/common/colormap/colormap.py 
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class ColorMap:
    """A color map is a function that linearly interpolate a set of color
    samples."""

    def __init__(self, samples: npt.NDArray):
        """Construct color map from color samples.

        Args:
            samples: A numpy array of shape (n, 3). Each row is a color sample.
        """
        assert len(samples) >= 2, "Color map must have at least 2 samples."
        self.samples = samples

    def __call__(self, value: float):
        """Evaluate color map at a value between 0 and 1.

        Args:
            value: A value between 0 and 1.

        Returns:
            (Color): The interpolated color.
        """
        value = max(0.0, min(1.0, value))

        n = len(self.samples) - 1
        i0 = math.floor(n * value)
        i1 = math.ceil(n * value)

        t = n * value - i0
        c0 = self.samples[i0]
        c1 = self.samples[i1]

        c = c0 * (1 - t) + c1 * t
        return Color(*c)

    def num_colors(self):
        """Number of color samples stored in this color map.

        Returns:
            (int): Number of colors in the color map.
        """
        return len(self.samples)

__init__(samples)

Construct color map from color samples.

Parameters:

Name Type Description Default
samples NDArray

A numpy array of shape (n, 3). Each row is a color sample.

 required
Source code in hakowan/common/colormap/colormap.py 
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def __init__(self, samples: npt.NDArray):
    """Construct color map from color samples.

    Args:
        samples: A numpy array of shape (n, 3). Each row is a color sample.
    """
    assert len(samples) >= 2, "Color map must have at least 2 samples."
    self.samples = samples

__call__(value)

Evaluate color map at a value between 0 and 1.

Parameters:

Name Type Description Default
value float

A value between 0 and 1.

 required

Returns:

Type Description
Color

The interpolated color.
Source code in hakowan/common/colormap/colormap.py 
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def __call__(self, value: float):
    """Evaluate color map at a value between 0 and 1.

    Args:
        value: A value between 0 and 1.

    Returns:
        (Color): The interpolated color.
    """
    value = max(0.0, min(1.0, value))

    n = len(self.samples) - 1
    i0 = math.floor(n * value)
    i1 = math.ceil(n * value)

    t = n * value - i0
    c0 = self.samples[i0]
    c1 = self.samples[i1]

    c = c0 * (1 - t) + c1 * t
    return Color(*c)

num_colors()

Number of color samples stored in this color map.

Returns:

Type Description
int

Number of colors in the color map.
Source code in hakowan/common/colormap/colormap.py 
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def num_colors(self):
    """Number of color samples stored in this color map.

    Returns:
        (int): Number of colors in the color map.
    """
    return len(self.samples)