.. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_misc_demo_agg_filter.py: =============== Demo Agg Filter =============== .. image:: /gallery/misc/images/sphx_glr_demo_agg_filter_001.png :alt: demo agg filter :class: sphx-glr-single-img .. code-block:: default import matplotlib.cm as cm import matplotlib.pyplot as plt import matplotlib.transforms as mtransforms from matplotlib.colors import LightSource from matplotlib.artist import Artist import numpy as np 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 A = np.apply_along_axis(smooth1d, 0, A, window_len) A = np.apply_along_axis(smooth1d, 1, A, window_len) return A class BaseFilter: def get_pad(self, dpi): return 0 def process_image(padded_src, dpi): raise NotImplementedError("Should be overridden by subclasses") def __call__(self, im, dpi): pad = self.get_pad(dpi) padded_src = np.pad(im, [(pad, pad), (pad, pad), (0, 0)], "constant") tgt_image = self.process_image(padded_src, dpi) return tgt_image, -pad, -pad class OffsetFilter(BaseFilter): def __init__(self, offsets=(0, 0)): 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 Gaussian filter.""" def __init__(self, sigma, alpha=0.5, color=(0, 0, 0)): self.sigma = sigma self.alpha = alpha self.color = color def get_pad(self, dpi): return int(self.sigma*3 / 72 * dpi) def process_image(self, padded_src, dpi): tgt_image = np.empty_like(padded_src) tgt_image[:, :, :3] = self.color tgt_image[:, :, 3] = smooth2d(padded_src[:, :, 3] * self.alpha, self.sigma / 72 * dpi) return tgt_image class DropShadowFilter(BaseFilter): def __init__(self, sigma, alpha=0.3, color=(0, 0, 0), offsets=(0, 0)): 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 class LightFilter(BaseFilter): def __init__(self, sigma, fraction=0.5): self.gauss_filter = GaussianFilter(sigma, alpha=1) self.light_source = LightSource() self.fraction = fraction 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] alpha = padded_src[:, :, 3:] rgb2 = self.light_source.shade_rgb(rgb, elevation, fraction=self.fraction) return np.concatenate([rgb2, alpha], -1) class GrowFilter(BaseFilter): """Enlarge the area.""" def __init__(self, pixels, color=(1, 1, 1)): self.pixels = pixels self.color = color def __call__(self, im, dpi): alpha = np.pad(im[..., 3], self.pixels, "constant") alpha2 = np.clip(smooth2d(alpha, self.pixels / 72 * dpi) * 5, 0, 1) new_im = np.empty((*alpha2.shape, 4)) new_im[:, :, :3] = self.color new_im[:, :, 3] = alpha2 offsetx, offsety = -self.pixels, -self.pixels return new_im, offsetx, offsety class FilteredArtistList(Artist): """A simple container to filter multiple artists at once.""" def __init__(self, artist_list, filter): super().__init__() self._artist_list = artist_list self._filter = filter 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() 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 = np.exp(-X**2 - Y**2) Z2 = np.exp(-(X - 1)**2 - (Y - 1)**2) Z = (Z1 - Z2) * 2 # draw ax.imshow(Z, interpolation='bilinear', origin='lower', cmap=cm.gray, extent=(-3, 3, -2, 2), aspect='auto') levels = np.arange(-1.2, 1.6, 0.2) CS = ax.contour(Z, levels, origin='lower', linewidths=2, extent=(-3, 3, -2, 2)) # contour label cl = ax.clabel(CS, levels[1::2], # label every second level inline=True, fmt='%1.1f', fontsize=11) # change clabel color to black from matplotlib.patheffects import Normal for t in cl: t.set_color("k") # to force TextPath (i.e., same font in all backends) t.set_path_effects([Normal()]) # 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-") l2, = ax.plot([0.1, 0.5, 0.9], [0.5, 0.2, 0.7], "ro-") 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): # Copied from barchart_demo.py N = 5 men_means = [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, men_means, width, color='r', ec="w", lw=2) women_means = [25, 32, 34, 20, 25] rects2 = ax.bar(ind + width + 0.1, women_means, 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_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) 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 __name__ == "__main__": fix, axs = plt.subplots(2, 2) filtered_text(axs[0, 0]) drop_shadow_line(axs[0, 1]) drop_shadow_patches(axs[1, 0]) light_filter_pie(axs[1, 1]) axs[1, 1].set_frame_on(True) plt.show() .. _sphx_glr_download_gallery_misc_demo_agg_filter.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: demo_agg_filter.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: demo_agg_filter.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_