Re: [Matplotlib-users] fading line plot
On 2/24/2013 1:28 PM, Paul Anton Letnes wrote: > Hi everyone, > > I've been looking into making an animation of a mechanical system. In its > first incarnation, my plan was as follows: > 1) Make a fading line plot of two variables (say, x and y) > 2) Run a series of such plots through ffmpeg/avencode to generate an animation > > First, I'm wondering whether there's a built-in way of making a fading line > plot, i.e. a plot where one end of the line is plotted with high alpha, the > other end with low alpha, and intermediate line segments with linearly scaled > alpha. For now, I've done this by manually "chunking" the x and y arrays and > plotting each chunk with different alpha. Is there a better way? Is there > interest in creating such a plotting function and adding it to matplotlib? > > Second, is there a way of integrating the "chunked" generation of fading > lines with the animation generating features of matplotlib? It seems > possible, although a bit clunky, at present, but maybe someone has a better > idea at what overall approach to take than I do. > > Cheers > Paul > -- > Everyone hates slow websites. So do we. > Make your web apps faster with AppDynamics > Download AppDynamics Lite for free today: > http://p.sf.net/sfu/appdyn_d2d_feb > ___ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users Paul, I've had to do something similar to what you need, and I found the following example from the Gallery quite helpful: http://matplotlib.org/examples/pylab_examples/multicolored_line.html I think the second plot in particular is pretty close to what you want; however, you'll need to set the alpha values manually. This is what I've done for line collections, scatter plots, etc. _ import numpy as np import matplotlib.pyplot as plt norm_data = np.random.rand(20) xs = np.random.rand(20) # Pick a colormap and generate the color array for your data cmap = plt.cm.spectral colors = cmap(norm_data) # Reset the alpha data using your desired values colors[:,3] = norm_data # Adding a colorbar is a bit of a pain here, need to use a mappable fig = plt.figure() plt.scatter(xs, norm_data, c=colors, s=55) mappable = plt.cm.ScalarMappable(cmap=cmap) mappable.set_array(norm_data) fig.colorbar(mappable) plt.show() _ Hope that helps a little. Ryan -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] fading line plot
On 24/02/2013 18:28, Paul Anton Letnes wrote: > Hi everyone, > > I've been looking into making an animation of a mechanical system. In its > first incarnation, my plan was as follows: > 1) Make a fading line plot of two variables (say, x and y) > 2) Run a series of such plots through ffmpeg/avencode to generate an animation > > First, I'm wondering whether there's a built-in way of making a fading line > plot, i.e. a plot where one end of the line is plotted with high alpha, the > other end with low alpha, and intermediate line segments with linearly scaled > alpha. For now, I've done this by manually "chunking" the x and y arrays and > plotting each chunk with different alpha. Is there a better way? Is there > interest in creating such a plotting function and adding it to matplotlib? > > Second, is there a way of integrating the "chunked" generation of fading > lines with the animation generating features of matplotlib? It seems > possible, although a bit clunky, at present, but maybe someone has a better > idea at what overall approach to take than I do. > > Cheers > Paul > -- > Everyone hates slow websites. So do we. > Make your web apps faster with AppDynamics > Download AppDynamics Lite for free today: > http://p.sf.net/sfu/appdyn_d2d_feb > I remember this http://www.johndcook.com/blog/2013/02/20/python-animation-for-mechanical-vibrations/ from a few days back, HTH. -- Cheers. Mark Lawrence -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
[Matplotlib-users] fading line plot
Hi everyone, I've been looking into making an animation of a mechanical system. In its first incarnation, my plan was as follows: 1) Make a fading line plot of two variables (say, x and y) 2) Run a series of such plots through ffmpeg/avencode to generate an animation First, I'm wondering whether there's a built-in way of making a fading line plot, i.e. a plot where one end of the line is plotted with high alpha, the other end with low alpha, and intermediate line segments with linearly scaled alpha. For now, I've done this by manually "chunking" the x and y arrays and plotting each chunk with different alpha. Is there a better way? Is there interest in creating such a plotting function and adding it to matplotlib? Second, is there a way of integrating the "chunked" generation of fading lines with the animation generating features of matplotlib? It seems possible, although a bit clunky, at present, but maybe someone has a better idea at what overall approach to take than I do. Cheers Paul -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
