.. 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_user_interfaces_svg_histogram_sgskip.py: ============= SVG Histogram ============= Demonstrate how to create an interactive histogram, in which bars are hidden or shown by clicking on legend markers. The interactivity is encoded in ecmascript (javascript) and inserted in the SVG code in a post-processing step. To render the image, open it in a web browser. SVG is supported in most web browsers used by Linux and OSX users. Windows IE9 supports SVG, but earlier versions do not. Notes ----- The matplotlib backend lets us assign ids to each object. This is the mechanism used here to relate matplotlib objects created in python and the corresponding SVG constructs that are parsed in the second step. While flexible, ids are cumbersome to use for large collection of objects. Two mechanisms could be used to simplify things: * systematic grouping of objects into SVG tags, * assigning classes to each SVG object according to its origin. For example, instead of modifying the properties of each individual bar, the bars from the `hist` function could either be grouped in a PatchCollection, or be assigned a class="hist_##" attribute. CSS could also be used more extensively to replace repetitive markup throughout the generated SVG. Author: david.huard@gmail.com .. code-block:: default import numpy as np import matplotlib.pyplot as plt import xml.etree.ElementTree as ET from io import BytesIO import json plt.rcParams['svg.fonttype'] = 'none' # Apparently, this `register_namespace` method works only with # python 2.7 and up and is necessary to avoid garbling the XML name # space with ns0. ET.register_namespace("", "http://www.w3.org/2000/svg") # Fixing random state for reproducibility np.random.seed(19680801) # --- Create histogram, legend and title --- plt.figure() r = np.random.randn(100) r1 = r + 1 labels = ['Rabbits', 'Frogs'] H = plt.hist([r, r1], label=labels) containers = H[-1] leg = plt.legend(frameon=False) plt.title("From a web browser, click on the legend\n" "marker to toggle the corresponding histogram.") # --- Add ids to the svg objects we'll modify hist_patches = {} for ic, c in enumerate(containers): hist_patches['hist_%d' % ic] = [] for il, element in enumerate(c): element.set_gid('hist_%d_patch_%d' % (ic, il)) hist_patches['hist_%d' % ic].append('hist_%d_patch_%d' % (ic, il)) # Set ids for the legend patches for i, t in enumerate(leg.get_patches()): t.set_gid('leg_patch_%d' % i) # Set ids for the text patches for i, t in enumerate(leg.get_texts()): t.set_gid('leg_text_%d' % i) # Save SVG in a fake file object. f = BytesIO() plt.savefig(f, format="svg") # Create XML tree from the SVG file. tree, xmlid = ET.XMLID(f.getvalue()) # --- Add interactivity --- # Add attributes to the patch objects. for i, t in enumerate(leg.get_patches()): el = xmlid['leg_patch_%d' % i] el.set('cursor', 'pointer') el.set('onclick', "toggle_hist(this)") # Add attributes to the text objects. for i, t in enumerate(leg.get_texts()): el = xmlid['leg_text_%d' % i] el.set('cursor', 'pointer') el.set('onclick', "toggle_hist(this)") # Create script defining the function `toggle_hist`. # We create a global variable `container` that stores the patches id # belonging to each histogram. Then a function "toggle_element" sets the # visibility attribute of all patches of each histogram and the opacity # of the marker itself. script = """ """ % json.dumps(hist_patches) # Add a transition effect css = tree.getchildren()[0][0] css.text = css.text + "g {-webkit-transition:opacity 0.4s ease-out;" + \ "-moz-transition:opacity 0.4s ease-out;}" # Insert the script and save to file. tree.insert(0, ET.XML(script)) ET.ElementTree(tree).write("svg_histogram.svg") .. _sphx_glr_download_gallery_user_interfaces_svg_histogram_sgskip.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: svg_histogram_sgskip.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: svg_histogram_sgskip.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_