.. _showcase-integral_demo: showcase example code: integral_demo.py ======================================= .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/showcase/integral_demo.py :: """ Plot demonstrating the integral as the area under a curve. Although this is a simple example, it demonstrates some important tweaks: * A simple line plot with custom color and line width. * A shaded region created using a Polygon patch. * A text label with mathtext rendering. * figtext calls to label the x- and y-axes. * Use of axis spines to hide the top and right spines. * Custom tick placement and labels. """ import numpy as np import matplotlib.pyplot as plt from matplotlib.patches import Polygon def func(x): return (x - 3) * (x - 5) * (x - 7) + 85 a, b = 2, 9 # integral limits x = np.linspace(0, 10) y = func(x) fig, ax = plt.subplots() plt.plot(x, y, 'r', linewidth=2) plt.ylim(ymin=0) # Make the shaded region ix = np.linspace(a, b) iy = func(ix) verts = [(a, 0)] + list(zip(ix, iy)) + [(b, 0)] poly = Polygon(verts, facecolor='0.9', edgecolor='0.5') ax.add_patch(poly) plt.text(0.5 * (a + b), 30, r"$\int_a^b f(x)\mathrm{d}x$", horizontalalignment='center', fontsize=20) plt.figtext(0.9, 0.05, '$x$') plt.figtext(0.1, 0.9, '$y$') ax.spines['right'].set_visible(False) ax.spines['top'].set_visible(False) ax.xaxis.set_ticks_position('bottom') ax.set_xticks((a, b)) ax.set_xticklabels(('$a$', '$b$')) ax.set_yticks([]) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:how-to-search-examples)