mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-30 17:24:52 +08:00
Tony S Yu
75 lines
2.5 KiB
Python
75 lines
2.5 KiB
Python
import numpy as np
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import matplotlib.pyplot as plt
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from matplotlib.colors import LinearSegmentedColormap
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__all__ = ['figimage', 'LinearColormap', 'ClearColormap']
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def figimage(image, scale=1, dpi=None, **kwargs):
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"""Return figure and axes with figure tightly surrounding image.
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Unlike pyplot.figimage, this actually plots onto an axes object, which
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fills the figure. Plotting the image onto an axes allows for subsequent
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overlays of axes artists.
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Parameters
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----------
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image : array
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image to plot
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scale : float
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If scale is 1, the figure and axes have the same dimension as the
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image. Smaller values of `scale` will shrink the figure.
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dpi : int
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Dots per inch for figure. If None, use the default rcParam.
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"""
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dpi = dpi if dpi is not None else plt.rcParams['figure.dpi']
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kwargs.setdefault('interpolation', 'nearest')
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kwargs.setdefault('cmap', 'gray')
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h, w, d = np.atleast_3d(image).shape
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figsize = np.array((w, h), dtype=float) / dpi * scale
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fig, ax = plt.subplots(figsize=figsize, dpi=dpi)
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fig.subplots_adjust(left=0, bottom=0, right=1, top=1)
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ax.set_axis_off()
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ax.imshow(image, **kwargs)
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return fig, ax
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class LinearColormap(LinearSegmentedColormap):
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"""LinearSegmentedColormap in which color varies smoothly.
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This class is a simplification of LinearSegmentedColormap, which doesn't
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support jumps in color intensities.
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Parameters
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----------
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name : str
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Name of colormap.
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segmented_data : dict
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Dictionary of 'red', 'green', 'blue', and (optionally) 'alpha' values.
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Each color key contains a list of `x`, `y` tuples. `x` must increase
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monotonically from 0 to 1 and corresponds to input values for a mappable
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object (e.g. an image). `y` corresponds to the color intensity.
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"""
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def __init__(self, name, segmented_data, **kwargs):
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segmented_data = dict((key, [(x, y, y) for x, y in value])
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for key, value in segmented_data.iteritems())
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LinearSegmentedColormap.__init__(self, name, segmented_data, **kwargs)
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class ClearColormap(LinearColormap):
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"""Color map that varies linearly from alpha = 0 to 1
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"""
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def __init__(self, rgb, max_alpha=1, name='clear_color'):
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r, g, b = rgb
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cg_speq = {'blue': [(0.0, b), (1.0, b)],
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'green': [(0.0, g), (1.0, g)],
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'red': [(0.0, r), (1.0, r)],
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'alpha': [(0.0, 0.0), (1.0, max_alpha)]}
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LinearColormap.__init__(self, name, cg_speq)
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