On Sat, Aug 8, 2009 at 6:17 AM, Kaushik Ghose<kaushik_gh...@hms.harvard.edu> wrote:
> (http://matplotlib.sourceforge.net/api/artist_api.html#matplotlib.patches.Rectangle) > e.g. set_height() to change the rectangles? > > e.g. code > ------------------------------ > import pylab > x = pylab.rand(20) > h = pylab.hist(x) > h[2][0].set_height(1) > pylab.draw() > -------------------------------- This is the right idea, but it is likely to be slow for animation, since each rectangle is a separate mpl object, each with its own graphics contexs, rendering step, etc. bar and hist were very early functions which I wrote before we had collections and compound paths. If I were rewriting it from scratch, I would use a compound path. It's a little more work upfront because you have to manually compute the vertices and path codes, but it will be goo-gobs faster. Here is the animated histogram for tk using compound paths """ This example shows how to use a path patch to draw a bunch of rectangles for an animated histogram """ import numpy as np import matplotlib matplotlib.use('TkAgg') # do this before importing pylab import matplotlib.pyplot as plt import matplotlib.patches as patches import matplotlib.path as path fig = plt.figure() ax = fig.add_subplot(111) # histogram our data with numpy data = np.random.randn(1000) n, bins = np.histogram(data, 100) # get the corners of the rectangles for the histogram left = np.array(bins[:-1]) right = np.array(bins[1:]) bottom = np.zeros(len(left)) top = bottom + n nrects = len(left) # here comes the tricky part -- we have to set up the vertex and path # codes arrays using moveto, lineto and closepoly # for each rect: 1 for the MOVETO, 3 for the LINETO, 1 for the # CLOSEPOLY; the vert for the closepoly is ignored but we still need # it to keep the codes aligned with the vertices nverts = nrects*(1+3+1) verts = np.zeros((nverts, 2)) codes = np.ones(nverts, int) * path.Path.LINETO codes[0::5] = path.Path.MOVETO codes[4::5] = path.Path.CLOSEPOLY verts[0::5,0] = left verts[0::5,1] = bottom verts[1::5,0] = left verts[1::5,1] = top verts[2::5,0] = right verts[2::5,1] = top verts[3::5,0] = right verts[3::5,1] = bottom barpath = path.Path(verts, codes) patch = patches.PathPatch(barpath, facecolor='green', edgecolor='yellow', alpha=0.5) ax.add_patch(patch) ax.set_xlim(left[0], right[-1]) ax.set_ylim(bottom.min(), top.max()) def animate(): # simulate new data coming in data = np.random.randn(1000) n, bins = np.histogram(data, 100) top = bottom + n verts[1::5,1] = top verts[2::5,1] = top fig.canvas.draw() def run(): for i in range(100): fig.canvas.manager.window.after(100, animate) fig.canvas.manager.window.after(100, run) plt.show()
histogram_tkagg.py
Description: Binary data
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