{ "metadata": { "signature": "sha256:12113b57f3dd9ec849fc169de6d42c92fd7f34fa4e324eb0a49aa71d56942622" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "Matplotlib: converting a matrix to a raster image\n", "======================================================================\n", "\n", "Scipy provides a command (imsave) to make a raster (png, jpg...) image\n", "from a 2D array, each pixel corresponding to one value of the array. Yet\n", "the image is black and white.\n", "\n", "Here is a recipy to do this with Matplotlib, and use a colormap to give\n", "color to the image." ] }, { "cell_type": "code", "collapsed": false, "input": [ "from matplotlib.pyplot import *\n", "from scipy import mgrid\n", "\n", "def imsave(filename, X, **kwargs):\n", " \"\"\" Homebrewed imsave to have nice colors... \"\"\"\n", " figsize=(array(X.shape)/100.0)[::-1]\n", " rcParams.update({'figure.figsize':figsize})\n", " fig = figure(figsize=figsize)\n", " axes([0,0,1,1]) # Make the plot occupy the whole canvas\n", " axis('off')\n", " fig.set_size_inches(figsize)\n", " imshow(X,origin='lower', **kwargs)\n", " savefig(filename, facecolor='black', edgecolor='black', dpi=100)\n", " close(fig)\n", "\n", "\n", "X,Y=mgrid[-5:5:0.1,-5:5:0.1]\n", "Z=sin(X**2+Y**2+1e-4)/(X**2+Y**2+1e-4) # Create the data to be plotted\n", "imsave('imsave.png', Z, cmap=cm.hot )" ], "language": "python", "metadata": {}, "outputs": [], "prompt_number": 1 }, { "cell_type": "code", "collapsed": false, "input": [ "imshow(imread('imsave.png'))" ], "language": "python", "metadata": {}, "outputs": [ { "metadata": {}, "output_type": "pyout", "prompt_number": 2, "text": [ "" ] }, { "metadata": {}, "output_type": "display_data", "png": 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"text": [ "" ] } ], "prompt_number": 2 } ], "metadata": {} } ] }