a wiggly line

//

// draw a wiggly line

// program for lectures on "The Wrong Way to Draw a Line"

//

// schien@mail.ncku.edu.tw, DPD 2023

//

​

function setup() {

  createCanvas(500, 500);

  frameRate(1);

}

​

function draw() {

  let y = width/2; 

  background(255);

  strokeWeight(5);

  stroke(0, 30);

  line(20, y, 480, y);  // draw a line

​

  stroke(20, 50, 70, 180);

  let step = random(10); 

  let lastx = -999; 

  let lasty = -999; 

  let border = 20; 

  for (let x=border; x<=width-border; x+=step) { 

    let ystep = random(20) - 10;

    y += ystep;

    if (lastx > -999) { 

       line(x, y, lastx, lasty); 

    } 

    lastx = x; 

    lasty = y; 

  }

}