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pylab_examples example code: demo_agg_filter.pyΒΆ

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../../_images/demo_agg_filter.png
import matplotlib.pyplot as plt

import numpy as np
import matplotlib.cm as cm
import matplotlib.mlab as mlab

def smooth1d(x, window_len):
    # copied from http://www.scipy.org/Cookbook/SignalSmooth

    s=np.r_[2*x[0]-x[window_len:1:-1],x,2*x[-1]-x[-1:-window_len:-1]]
    w = np.hanning(window_len)
    y=np.convolve(w/w.sum(),s,mode='same')
    return y[window_len-1:-window_len+1]

def smooth2d(A, sigma=3):

    window_len = max(int(sigma), 3)*2+1
    A1 = np.array([smooth1d(x, window_len) for x in np.asarray(A)])
    A2 = np.transpose(A1)
    A3 = np.array([smooth1d(x, window_len) for x in A2])
    A4 = np.transpose(A3)

    return A4




class BaseFilter(object):
    def prepare_image(self, src_image, dpi, pad):
        ny, nx, depth = src_image.shape
        #tgt_image = np.zeros([pad*2+ny, pad*2+nx, depth], dtype="d")
        padded_src = np.zeros([pad*2+ny, pad*2+nx, depth], dtype="d")
        padded_src[pad:-pad, pad:-pad,:] = src_image[:,:,:]

        return padded_src#, tgt_image

    def get_pad(self, dpi):
        return 0

    def __call__(self, im, dpi):
        pad = self.get_pad(dpi)
        padded_src = self.prepare_image(im, dpi, pad)
        tgt_image = self.process_image(padded_src, dpi)
        return tgt_image, -pad, -pad


class OffsetFilter(BaseFilter):
    def __init__(self, offsets=None):
        if offsets is None:
            self.offsets = (0, 0)
        else:
            self.offsets = offsets

    def get_pad(self, dpi):
        return int(max(*self.offsets)/72.*dpi)

    def process_image(self, padded_src, dpi):
        ox, oy = self.offsets
        a1 = np.roll(padded_src, int(ox/72.*dpi), axis=1)
        a2 = np.roll(a1, -int(oy/72.*dpi), axis=0)
        return a2

class GaussianFilter(BaseFilter):
    "simple gauss filter"
    def __init__(self, sigma, alpha=0.5, color=None):
        self.sigma = sigma
        self.alpha = alpha
        if color is None:
            self.color=(0, 0, 0)
        else:
            self.color=color

    def get_pad(self, dpi):
        return int(self.sigma*3/72.*dpi)


    def process_image(self, padded_src, dpi):
        #offsetx, offsety = int(self.offsets[0]), int(self.offsets[1])
        tgt_image = np.zeros_like(padded_src)
        aa = smooth2d(padded_src[:,:,-1]*self.alpha,
                      self.sigma/72.*dpi)
        tgt_image[:,:,-1] = aa
        tgt_image[:,:,:-1] = self.color
        return tgt_image

class DropShadowFilter(BaseFilter):
    def __init__(self, sigma, alpha=0.3, color=None, offsets=None):
        self.gauss_filter = GaussianFilter(sigma, alpha, color)
        self.offset_filter = OffsetFilter(offsets)

    def get_pad(self, dpi):
        return max(self.gauss_filter.get_pad(dpi),
                   self.offset_filter.get_pad(dpi))

    def process_image(self, padded_src, dpi):
        t1 = self.gauss_filter.process_image(padded_src, dpi)
        t2 = self.offset_filter.process_image(t1, dpi)
        return t2


from matplotlib.colors import LightSource

class LightFilter(BaseFilter):
    "simple gauss filter"
    def __init__(self, sigma, fraction=0.5):
        self.gauss_filter = GaussianFilter(sigma, alpha=1)
        self.light_source = LightSource()
        self.fraction = fraction
        #hsv_min_val=0.5,hsv_max_val=0.9,
        #                                hsv_min_sat=0.1,hsv_max_sat=0.1)
    def get_pad(self, dpi):
        return self.gauss_filter.get_pad(dpi)

    def process_image(self, padded_src, dpi):
        t1 = self.gauss_filter.process_image(padded_src, dpi)
        elevation = t1[:,:,3]
        rgb = padded_src[:,:,:3]

        rgb2 = self.light_source.shade_rgb(rgb, elevation,
                                           fraction=self.fraction)

        tgt = np.empty_like(padded_src)
        tgt[:,:,:3] = rgb2
        tgt[:,:,3] = padded_src[:,:,3]

        return tgt



class GrowFilter(BaseFilter):
    "enlarge the area"
    def __init__(self, pixels, color=None):
        self.pixels = pixels
        if color is None:
            self.color=(1, 1, 1)
        else:
            self.color=color

    def __call__(self, im, dpi):
        pad = self.pixels
        ny, nx, depth = im.shape
        new_im = np.empty([pad*2+ny, pad*2+nx, depth], dtype="d")
        alpha = new_im[:,:,3]
        alpha.fill(0)
        alpha[pad:-pad, pad:-pad] = im[:,:,-1]
        alpha2 = np.clip(smooth2d(alpha, self.pixels/72.*dpi) * 5, 0, 1)
        new_im[:,:,-1] = alpha2
        new_im[:,:,:-1] = self.color
        offsetx, offsety = -pad, -pad

        return new_im, offsetx, offsety


from matplotlib.artist import Artist

class FilteredArtistList(Artist):
    """
    A simple container to draw filtered artist.
    """
    def __init__(self, artist_list, filter):
        self._artist_list = artist_list
        self._filter = filter
        Artist.__init__(self)

    def draw(self, renderer):
        renderer.start_rasterizing()
        renderer.start_filter()
        for a in self._artist_list:
            a.draw(renderer)
        renderer.stop_filter(self._filter)
        renderer.stop_rasterizing()



import matplotlib.transforms as mtransforms

def filtered_text(ax):
    # mostly copied from contour_demo.py

    # prepare image
    delta = 0.025
    x = np.arange(-3.0, 3.0, delta)
    y = np.arange(-2.0, 2.0, delta)
    X, Y = np.meshgrid(x, y)
    Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
    Z2 = mlab.bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
    # difference of Gaussians
    Z = 10.0 * (Z2 - Z1)


    # draw
    im = ax.imshow(Z, interpolation='bilinear', origin='lower',
                   cmap=cm.gray, extent=(-3,3,-2,2))
    levels = np.arange(-1.2, 1.6, 0.2)
    CS = ax.contour(Z, levels,
                    origin='lower',
                    linewidths=2,
                    extent=(-3,3,-2,2))

    ax.set_aspect("auto")

    # contour label
    cl = ax.clabel(CS, levels[1::2],  # label every second level
                   inline=1,
                   fmt='%1.1f',
                   fontsize=11)

    # change clable color to black
    from matplotlib.patheffects import Normal
    for t in cl:
        t.set_color("k")
        t.set_path_effects([Normal()]) # to force TextPath (i.e., same font in all backends)

    # Add white glows to improve visibility of labels.
    white_glows = FilteredArtistList(cl, GrowFilter(3))
    ax.add_artist(white_glows)
    white_glows.set_zorder(cl[0].get_zorder()-0.1)

    ax.xaxis.set_visible(False)
    ax.yaxis.set_visible(False)


def drop_shadow_line(ax):
    # copied from examples/misc/svg_filter_line.py

    # draw lines
    l1, = ax.plot([0.1, 0.5, 0.9], [0.1, 0.9, 0.5], "bo-",
                  mec="b", mfc="w", lw=5, mew=3, ms=10, label="Line 1")
    l2, = ax.plot([0.1, 0.5, 0.9], [0.5, 0.2, 0.7], "ro-",
                  mec="r", mfc="w", lw=5, mew=3, ms=10, label="Line 1")


    gauss = DropShadowFilter(4)

    for l in [l1, l2]:

        # draw shadows with same lines with slight offset.

        xx = l.get_xdata()
        yy = l.get_ydata()
        shadow, = ax.plot(xx, yy)
        shadow.update_from(l)

        # offset transform
        ot = mtransforms.offset_copy(l.get_transform(), ax.figure,
                                     x=4.0, y=-6.0, units='points')

        shadow.set_transform(ot)


        # adjust zorder of the shadow lines so that it is drawn below the
        # original lines
        shadow.set_zorder(l.get_zorder()-0.5)
        shadow.set_agg_filter(gauss)
        shadow.set_rasterized(True) # to support mixed-mode renderers



    ax.set_xlim(0., 1.)
    ax.set_ylim(0., 1.)

    ax.xaxis.set_visible(False)
    ax.yaxis.set_visible(False)




def drop_shadow_patches(ax):
    # copyed from barchart_demo.py
    N = 5
    menMeans = (20, 35, 30, 35, 27)

    ind = np.arange(N)  # the x locations for the groups
    width = 0.35       # the width of the bars

    rects1 = ax.bar(ind, menMeans, width, color='r', ec="w", lw=2)

    womenMeans = (25, 32, 34, 20, 25)
    rects2 = ax.bar(ind+width+0.1, womenMeans, width, color='y', ec="w", lw=2)

    #gauss = GaussianFilter(1.5, offsets=(1,1), )
    gauss = DropShadowFilter(5, offsets=(1,1), )
    shadow = FilteredArtistList(rects1+rects2, gauss)
    ax.add_artist(shadow)
    shadow.set_zorder(rects1[0].get_zorder()-0.1)

    ax.set_xlim(ind[0]-0.5, ind[-1]+1.5)
    ax.set_ylim(0, 40)

    ax.xaxis.set_visible(False)
    ax.yaxis.set_visible(False)


def light_filter_pie(ax):
    fracs = [15,30,45, 10]
    explode=(0, 0.05, 0, 0)
    pies = ax.pie(fracs, explode=explode)
    ax.patch.set_visible(True)

    light_filter = LightFilter(9)
    for p in pies[0]:
        p.set_agg_filter(light_filter)
        p.set_rasterized(True) # to support mixed-mode renderers
        p.set(ec="none",
              lw=2)

    gauss = DropShadowFilter(9, offsets=(3,4), alpha=0.7)
    shadow = FilteredArtistList(pies[0], gauss)
    ax.add_artist(shadow)
    shadow.set_zorder(pies[0][0].get_zorder()-0.1)


if 1:

    plt.figure(1, figsize=(6, 6))
    plt.subplots_adjust(left=0.05, right=0.95)

    ax = plt.subplot(221)
    filtered_text(ax)

    ax = plt.subplot(222)
    drop_shadow_line(ax)

    ax = plt.subplot(223)
    drop_shadow_patches(ax)

    ax = plt.subplot(224)
    ax.set_aspect(1)
    light_filter_pie(ax)
    ax.set_frame_on(True)

    plt.show()

Keywords: python, matplotlib, pylab, example, codex (see Search examples)