无缝四分之一圆和半圆背景效果-html代码-BFW代码库

无缝四分之一圆和半圆背景效果

代码语言：html

所属分类：背景

代码描述：无缝四分之一圆和半圆背景效果

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">

<style>
body {
  font-family: Arial, Helvetica, "Liberation Sans", FreeSans, sans-serif;
  background-color: #000;
  color: #fff;
  margin: 0;
  padding: 0;
  border-width:0;
  cursor:pointer;
}
</style>

</head>
<body translate="no">


<script>
"use strict";

/* Inspired by Johan Karlsson'n pen Quarter Circle and Half a Circle
              https://codepen.io/DonKarlssonSan/details/abvRErd
              vertices are numberered 0 (NW), 1(NE), 2(SE) and 3(SW)
              sides are numered 0(N), 1(E), 2(S) and 3(W)
              */
window.onload = function () {

  const sideMin = 50;
  const sideMax = 120;

  let canv, ctx; // canvas and context
  let maxx, maxy;
  let side; // side of square
  let nbx, nby; // number of squares in width / height
  let orgx, orgy; // coordinates of top left corner of grid[0][0]
  let grid;
  let colors;

  /* for animation */
  let events = [];

  // shortcuts for Math.…

  const mrandom = Math.random;
  const mfloor = Math.floor;
  const mround = Math.round;
  const mceil = Math.ceil;
  const mabs = Math.abs;
  const mmin = Math.min;
  const mmax = Math.max;

  const mPI = Math.PI;
  const mPIS2 = Math.PI / 2;
  const m2PI = Math.PI * 2;
  const msin = Math.sin;
  const mcos = Math.cos;
  const matan2 = Math.atan2;

  const mhypot = Math.hypot;
  const msqrt = Math.sqrt;

  const rac3 = msqrt(3);
  const rac3s2 = rac3 / 2;
  const mPIS3 = Math.PI / 3;

  //-----------------------------------------------------------------

  function intAlea(min, max) {
    // random integer number [min..max[ . If no max is provided, [0..min[

    if (typeof max == 'undefined') {
      max = min;min = 0;
    }
    return mfloor(min + (max - min) * mrandom());
  } // intAlea

  //-----------------------------------------------------------------

  function createGrid() {
    /* attribute color 0, 1 or 2 to every square side
                         so that :
                           - each square uses the 3 colors (two are use once, one is used twice
                           on sides of a same vertex)
                           - matching sides of neighbour square are the same color
                         */

    let elem;
    grid = [];
    for (let ky = 0; ky < nby; ++ky) {
      grid[ky] = [];
      for (let kx = 0; kx < nbx; ++kx) {

        grid[ky][kx] = elem = [];
        // copy constraint f.........完整代码请登录后点击上方下载按钮下载查看