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| Keywords: Transmission line animation2.gif en A wave traveling right along a lossless transmission line Red color indicates high voltage and blue indicates low voltage Black dots represent electrons 2014-10-27 09 53 12 own Steven Byrnes other versions cc-zero Source code <source lang python > C Steven Byrnes 2014 This code is released under the MIT license http //opensource org/licenses/MIT This code runs in Python 2 7 or 3 3 It requires imagemagick to be installed; that's how it assembles images into animated GIFs from __future__ import division import pygame as pg from numpy import cos pi sin asarray import subprocess os directory_now os path dirname os path realpath __file__ frames_in_anim 75 animation_loop_seconds 5 time in seconds for animation to loop one cycle bgcolor 255 255 255 white ecolor 0 0 0 electron color is black pygame draws pixel-art not smoothed Therefore I am drawing it bigger then smoothly shrinking it down img_height 210 img_width 900 final_height 70 final_width 300 ~23 megapixel limit for wikipedia animated gifs assert final_height final_width frames_in_anim < 22e6 transmission line wire length and thickness and y-coordinate of each wire tl_length img_width tl_thickness 27 tl_top_y 66 tl_bot_y img_height - tl_top_y - tl_thickness + 2 wavelength 1 4 tl_length def rgb_from_V V voltage V varies -1 to +1 Return a color as a function of V Color is a 3-tuple red green blue each 0 to 255 return 200+55 V 200-55 V 200-55 V def tup_round tup round each element of a tuple to nearest integer return tuple int round x for x in tup def make_wire_surf phase_at_left make a pygame surface representing a colored wire startphase is phase at left side of the wire imgarray rgb_from_V cos phase_at_left + 2 pi x/wavelength for y in range tl_thickness for x in range tl_length return pg surfarray make_surface asarray imgarray def e_path param phase_top_left as param goes 0 to 1 this returns 'pos' x y 'phase' phi where x y is the coordinates of the corresponding point on the electron dot path and phi is the phase for an electron at that point on the path phase_top_left is phase of the left side of the top wire d is a vertical offset between the electrons and the wires d -21 pad is how far to extend the transmission line beyond the image borders since those electrons may enter the image a bit pad 36 path_length 2 tl_length + 2 pad howfar param path_length move right across top transmission line if howfar < path_length / 2 x howfar - pad y tl_top_y - d phase phase_top_left + 2 pi x / wavelength return 'pos' x y 'phase' phase then move left across the bottom transmission line x path_length - howfar - pad y tl_bot_y + tl_thickness + d phase phase_top_left + 2 pi x / wavelength return 'pos' x y 'phase' phase def main Make and save a drawing for each frame filename_list os path join directory_now 'temp' + str n + ' png' for n in range frames_in_anim for frame in range frames_in_anim phase_top_left -2 pi frame / frames_in_anim initialize surface surf pg Surface img_width img_height surf fill bgcolor ; draw transmission line top_wire_surf make_wire_surf phase_top_left bottom_wire_surf make_wire_surf phase_top_left + pi surf blit top_wire_surf 0 tl_top_y surf blit bottom_wire_surf 0 tl_bot_y draw electrons num_electrons 70 equilibrium_params x/ num_electrons-1 for x in range num_electrons phases e_path a phase_top_left 'phase' for a in equilibrium_params now_params equilibrium_paramsi + sin phasesi / 0 45 num_electrons for i in range num_electrons coords e_path a phase_top_left 'pos' for a in now_params for coord in coords pg draw circle surf ecolor tup_round coord 4 0 shrunk_surface pg transform smoothscale surf final_width final_height pg image save shrunk_surface filename_listframe seconds_per_frame animation_loop_seconds / frames_in_anim frame_delay str int seconds_per_frame 100 Use the convert command part of ImageMagick to build the animation command_list 'convert' '-delay' frame_delay '-loop' '0' + filename_list + 'anim gif' subprocess call command_list cwd directory_now Earlier we saved an image file for each frame of the animation Now that the animation is assembled we can optionally delete those files if True for filename in filename_list os remove filename main </source> Uploaded with UploadWizard Transmission lines Animations of electronics Impedance Animations of vibrations and waves Images with Python source code | ||||
