用Python和MoviePy将数据动态可视化_程序人生

Python有些出色的数据可视化库，但很少能渲染GIF或视频动画。本文介绍如何运用MoviePy作为其他库的通用动画插件。

有了 MoviePy ，你可以用一个函数 make_frame(t) 自定义动画，并返回相应的时间t的视频帧（秒）：

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from moviepy.editor import VideoClip def make_frame(t): \”\”\” returns an image of the frame at time t \”\”\” # … create the frame with any library return frame_for_time_t # (Height x Width x 3) Numpy array animation = VideoClip(make_frame, duration=3) # 3-second clip # For the export, many options/formats/optimizations are supportedanimation.write_videofile(\”my_animation.mp4\”, fps=24) # export as videoanimation.write_gif(\”my_animation.gif\”, fps=24) # export as GIF (slow)

在之前的文章中，我用这种方法来做制作矢量图形动画（用Gizeh库），和光线追踪三维场景（由POV-Ray做出）。这篇文章包括 MayaVi、vispy、matplotlib、NumPy 和 Scikit-image 这些科学库。

用Mayavi的动画

Mayavi是一个针对有简单接口的交互3D数据可视化的Python模块。在第一个例子中，我们做一个高度随时间t变化的表面的动画：

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import numpy as npimport mayavi.mlab as mlabimport moviepy.editor as mpy duration= 2 # duration of the animation in seconds (it will loop) # MAKE A FIGURE WITH MAYAVI fig_myv = mlab.figure(size=(220,220), bgcolor=(1,1,1))X, Y = np.linspace(–2,2,200), np.linspace(–2,2,200)XX, YY = np.meshgrid(X,Y)ZZ = lambda d: np.sinc(XX**2+YY**2)+np.sin(XX+d) # ANIMATE THE FIGURE WITH MOVIEPY, WRITE AN ANIMATED GIF def make_frame(t): mlab.clf() # clear the figure (to reset the colors) mlab.mesh(YY,XX,ZZ(2*np.pi*t/duration), figure=fig_myv) return mlab.screenshot(antialiased=True) animation = mpy.VideoClip(make_frame, duration=duration)animation.write_gif(\”sinc.gif\”, fps=20)

另一个例子是一个坐标和观看角度都随时间变化的线框网：

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import numpy as npimport mayavi.mlab as mlabimport moviepy.editor as mpy duration = 2 # duration of the animation in seconds (it will loop) # MAKE A FIGURE WITH MAYAVI fig = mlab.figure(size=(500, 500), bgcolor=(1,1,1)) u = np.linspace(0,2*np.pi,100)xx,yy,zz = np.cos(u), np.sin(3*u), np.sin(u) # Pointsl = mlab.plot3d(n>) # Pointsl = mlab.plot3d(thon有些出色的数据可视化库，但很少能渲染GIF或视频动画。本文介绍如何运用MoviePy作为其他库的通用动画插件。