Processing.py 中的“动画”运动

Question

I need to animate the movement of some linkages in processing . I use processing.py

I tried a toy example where I move a line segment across the screen. My idea was to: 1) draw the line 2) delay for a second 3) erase the screen 4) change the location of the line 5) repeat.

But my code doesn't work. It increments through, but ultimately only shows the final line location. I never see the intermediate step lines.

import math

def setup():
    size(800, 500)
    noLoop()

def draw():

    line(100,100,200,200)
    delay(100)

    x1,y1,x2,y2 = (100,100,200,200)

    for chunk in range(10,100,10):
        print(chunk)
        background(255)
        line(x1,y1,x2,y2)
        delay(1000)
        x2 += chunk

Answer 1

Read the documentation of draw() :

[...] All Processing programs update the screen at the end of draw() , never earlier.

In processing draw() is executed continuously, thus you do not need a loop. Increment x2 in draw and control the frames per second by frameRate

x1,y1,x2,y2 = (100,100,200,200)
chunk = 10

def setup():
    size(800, 500)
    frameRate(10)

def draw():
    global x2

    background(255)
    line(x1,y1,x2,y2)
    x2 += chunk