交通灯序列
交通灯序列
提问于 2016-02-11 14:47:18
我使用数组和if语句创建了一个功能正常的自动交通灯序列。这一切都是正确的，但我想知道我还能做些什么来改进我的代码，而不改变它的结构或工作方式，也不需要使用字典等等。
<!DOCTYPE html>
<head>
<title> Traffic Light</title>
<style>
.rainbow {
background-image: -webkit-gradient( linear, left top, right top, color-stop(0, red), color-stop(0.1, yellow), color-stop(0.2, green));
background-image: gradient( linear, left top, right top, color-stop(0, #f22), color-stop(0.15, #f2f), color-stop(0.3, #22f), color-stop(0.45, #2ff), color-stop(0.6, #2f2),color-stop(0.75, #2f2), color-stop(0.9, #ff2), color-stop(1, #f22) );
color:transparent;
-webkit-background-clip: text;
background-clip: text;
}
</style>
</head>
<body background="street.gif">
<h1 class="rainbow">Traffic Light</h1>
<canvas id="myCanvas" width="200" height="300"
style="border:1px solid #000000;">
Your browser does not support the HTML5 canvas tag.
</canvas>
<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.rect(0, 0, 200, 300);
ctx.fillStyle = "grey";
ctx.fill();
var colours=["red", "yellow", "green", "black","red yellow"];
var current=colours[0];
function offlight() {
ctx.beginPath();
ctx.arc(95,50,40,10,12*Math.PI);
ctx.fillStyle = "black";
ctx.fill();
ctx.stroke();
}
function offlight1() {
ctx.beginPath();
ctx.arc(95,150,40,10,12*Math.PI);
ctx.fillStyle = "black";
ctx.fill();
ctx.stroke();
}
function offlight2() {
ctx.beginPath();
ctx.arc(95,250,40,10,12*Math.PI);
ctx.fillStyle = "black";
ctx.fill();
ctx.stroke();
}
function drawLight1() {
ctx.beginPath();
ctx.arc(95,50,40,10,12*Math.PI);
ctx.fillStyle = "red";
ctx.fill();
ctx.stroke();
}
function drawLight2() {
ctx.beginPath();
ctx.arc(95,150,40,10,12*Math.PI);
ctx.fillStyle = "yellow";
ctx.fill();
ctx.stroke();
}
function drawLight3() {
ctx.beginPath();
ctx.arc(95,250,40,10,12*Math.PI);
ctx.fillStyle = "green";
ctx.fill();
ctx.stroke();
}
function changelight(){
if (current==colours[0]){
drawLight1();
offlight1();
offlight2();
current=colours[4]
} else if (current==colours[4]){
drawLight1();
drawLight2();
offlight2();
current=colours[2]
} else if (current==colours[2]) {
offlight();
offlight1();
drawLight3();
current=colours[3]
} else if (current==colours[3]){
offlight();
drawLight2();
offlight2();
current=colours[0]
}
}
setInterval(changelight,1000);
</script>
<br><br>
<button onclick="changelight()">Click</button>
</body>
</html>回答 1
Code Review用户
回答已采纳
发布于 2016-02-11 14:49:14
啊，你把你的<h1>搬到<body>里了。你到底在找什么？文件大小(->代码缩减)？速度优化？
一件简单的事情是使用parameters来减少代码重复：
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.rect(0, 0, 200, 300);
ctx.fillStyle = "grey";
ctx.fill();
var colours = ["red", "yellow", "green", "red yellow"];
var current = colours[0];
function offlight(a1) {
ctx.beginPath();
ctx.arc(95, a1, 40, 10, 12 * Math.PI);
ctx.fillStyle = "black";
ctx.fill();
ctx.stroke();
}
function drawLight(a1, fillParam) {
ctx.beginPath();
ctx.arc(95, a1, 40, 10, 12 * Math.PI);
ctx.fillStyle = fillParam;
ctx.fill();
ctx.stroke();
}
function changelight() {
if (current == colours[0]) {
drawLight(50, "red");
offlight(150);
offlight(250);
current = colours[4]
} else if (current == colours[4]) {
drawLight(50, "red");
drawLight(150, "yellow");
offlight(250);
current = colours[2]
} else if (current == colours[2]) {
offlight(50);
offlight(150);
drawLight(250, "green");
current = colours[1]
} else if (current == colours[1]) {
offlight(50);
drawLight(150, "yellow");
offlight(250);
current = colours[0]
}
}
setInterval(changelight, 1000);你用过颜色吗？(“黄色”)
您还可以删除空白空间，缩短变量和函数名。还可以考虑将JS移动到一个单独的文件中。
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原文链接：
https://codereview.stackexchange.com/questions/119646
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