Add logo generation from skimage main repo

.gitignore

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+__pycache__
+*~

logo/Makefile

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+.PHONY: logo
+
+logo: green_orange_snake.png snake_logo.svg
+	inkscape --export-png=scikit_image_logo.png --export-dpi=100 \
+		     --export-area-drawing --export-background-opacity=1 \
+			 snake_logo.svg
+	python shrink_logo.py
+
+green_orange_snake.png:
+	python scikit_image_logo.py --no-plot
+

logo/scikit_image_logo.py

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+"""
+Script to draw skimage logo using Scipy logo as stencil. The easiest
+starting point is the `plot_colorized_logo`.
+
+Original snake image from pixabay [1]_
+
+.. [1] http://pixabay.com/en/snake-green-toxic-close-yellow-3237/
+"""
+import sys
+if len(sys.argv) != 2 or sys.argv[1] != '--no-plot':
+    print("Run with '--no-plot' flag to generate logo silently.")
+else:
+    import matplotlib as mpl
+    mpl.use('Agg')
+import matplotlib.pyplot as plt
+
+import numpy as np
+
+import skimage.io as sio
+from skimage import img_as_float
+from skimage.color import gray2rgb, rgb2gray
+from skimage.exposure import rescale_intensity
+from skimage.filters import sobel
+
+import scipy_logo
+
+# Utility functions
+# =================
+
+def colorize(image, color, whiten=False):
+    """Return colorized image from gray scale image.
+
+    The colorized image has values from ranging between black at the lowest
+    intensity to `color` at the highest. If `whiten=True`, then the color
+    ranges from `color` to white.
+    """
+    color = np.asarray(color)[np.newaxis, np.newaxis, :]
+    image = image[:, :, np.newaxis]
+    if whiten:
+        # truncate and stretch intensity range to enhance contrast
+        image = rescale_intensity(image, in_range=(0.3, 1))
+        return color * (1 - image) + image
+    else:
+        return image * color
+
+
+def prepare_axes(ax):
+    plt.sca(ax)
+    ax.xaxis.set_visible(False)
+    ax.yaxis.set_visible(False)
+    for spine in ax.spines.values():
+        spine.set_visible(False)
+
+
+# Logo generating classes
+# =======================
+
+class LogoBase(object):
+
+    def __init__(self):
+        self.logo = scipy_logo.ScipyLogo(radius=self.radius)
+        self.mask_1 = self.logo.get_mask(self.image.shape, 'upper left')
+        self.mask_2 = self.logo.get_mask(self.image.shape, 'lower right')
+
+        edges = np.array([sobel(img) for img in self.image.T]).T
+        # truncate and stretch intensity range to enhance contrast
+        self.edges = rescale_intensity(edges, in_range=(0, 0.4))
+
+    def _crop_image(self, image):
+        w = 2 * self.radius
+        x, y = self.origin
+        return image[y:y + w, x:x + w]
+
+    def plot_curve(self, **kwargs):
+        self.logo.plot_snake_curve(**kwargs)
+
+
+class SnakeLogo(LogoBase):
+
+    radius = 250
+    origin = (420, 0)
+
+    def __init__(self):
+        image = sio.imread('data/snake_pixabay.jpg')
+        image = self._crop_image(image)
+        self.image = img_as_float(image)
+
+        LogoBase.__init__(self)
+
+
+snake_color = SnakeLogo()
+snake = SnakeLogo()
+# turn RGB image into gray image
+snake.image = rgb2gray(snake.image)
+snake.edges = rgb2gray(snake.edges)
+
+
+# Demo plotting functions
+# =======================
+
+def plot_colorized_logo(logo, color, edges='light', whiten=False):
+    """Convenience function to plot artificially-colored logo.
+
+    The upper-left half of the logo is an edge filtered image, while the
+    lower-right half is unfiltered.
+
+    Parameters
+    ----------
+    logo : LogoBase instance
+    color : length-3 sequence of floats or 2 length-3 sequences
+        RGB color spec. Float values should be between 0 and 1.
+    edges : {'light'|'dark'}
+        Specifies whether Sobel edges are drawn light or dark
+    whiten : bool or 2 bools
+        If True, a color value less than 1 increases the image intensity.
+    """
+    if not hasattr(color[0], '__iter__'):
+        color = [color] * 2  # use same color for upper-left & lower-right
+    if not hasattr(whiten, '__iter__'):
+        whiten = [whiten] * 2  # use same setting for upper-left & lower-right
+
+    image = gray2rgb(np.ones_like(logo.image))
+    mask_img = gray2rgb(logo.mask_2)
+    mask_edge = gray2rgb(logo.mask_1)
+
+    # Compose image with colorized image and edge-image.
+    if edges == 'dark':
+        logo_edge = colorize(1 - logo.edges, color[0], whiten=whiten[0])
+    else:
+        logo_edge = colorize(logo.edges, color[0], whiten=whiten[0])
+    logo_img = colorize(logo.image, color[1], whiten=whiten[1])
+    image[mask_img] = logo_img[mask_img]
+    image[mask_edge] = logo_edge[mask_edge]
+
+    logo.plot_curve(lw=5, color='w')  # plot snake curve on current axes
+    plt.imshow(image)
+
+
+if __name__ == '__main__':
+    # Colors to use for the logo:
+    red = (1, 0, 0)
+    blue = (0.35, 0.55, 0.85)
+    green_orange = ((0.6, 0.8, 0.3), (1, 0.5, 0.1))
+
+    def plot_all():
+        color_list = [red, blue, green_orange]
+        edge_list = ['light', 'dark']
+        f, axes = plt.subplots(nrows=len(edge_list), ncols=len(color_list))
+        for axes_row, edges in zip(axes, edge_list):
+            for ax, color in zip(axes_row, color_list):
+                prepare_axes(ax)
+                plot_colorized_logo(snake, color, edges=edges)
+        plt.tight_layout()
+
+    def plot_official_logo():
+        f, ax = plt.subplots()
+        prepare_axes(ax)
+        plot_colorized_logo(snake, green_orange, edges='dark',
+                            whiten=(False, True))
+        plt.savefig('green_orange_snake.png', bbox_inches='tight')
+
+    plot_all()
+    plot_official_logo()
+
+    plt.show()