let widthInInches = 40;

let heightInInches = 4;

let boxSizeInInches = 1; // width between imaginary grid lines

let lineWidthInInches = .1; // width of the actual drawn black lines

​

let saveImage = false; // set to true before you run when you want to save

​

/*

let strokeWidth = 1;

let boxSize = 100;

let screenWidth = 300;

let screenHeight = 300;

*/

​

​

let progress = 0;

​

function setup() {

    console.log("Process started. Generating image.");

    screenWidth = pixelsPerInch * widthInInches;

    screenHeight = pixelsPerInch * heightInInches;

    boxSize = boxSizeInInches * pixelsPerInch;

    strokeWidth = lineWidthInInches * pixelsPerInch;

    let BLACK = color(0);

    let WHITE = color(255);

    createCanvas(screenWidth, screenHeight);

    background(WHITE);

    strokeWeight(strokeWidth);

    stroke(BLACK);

    for (i = 0; i < screenWidth; i += boxSize) {

        for (j = 0; j < screenHeight; j += boxSize) {

            theLine(int(random(4)));

        }

      progress = 100 * (i*j) / (screenWidth * screenHeight);

      console.log(progress + "% completed");

    }

  if(saveImage)

    saveCanvas('image','png');

}

​

function draw() {}

​

function theLine(dir) {

    switch (dir) {

        case 0:

            line(i + boxSize / 2, j, i + boxSize / 2, j + boxSize);

            break;

        case 1:

            line(i, j, i + boxSize, j + boxSize);

            break;

        case 2:

            line(i + boxSize, j, i, j + boxSize);

            break;

        case 3:

            line(i, j + boxSize / 2, i + boxSize, j + boxSize / 2);

            break;

    }

}

​

​

​