<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title> Canvas 繪圖</title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="cloud">
<meta name="Keywords" content="H5 Canvas 繪圖">
<meta name="Description" content="使用Html5 Canvas 繪製圖形">
</head>
<style type="text/css">
#canvas{
border: 1px solid #000;
display:block;
margin: 50px auto;
}
</style>
<body>
<canvas id="canvas">
您的瀏覽器不支持Canvas
</canvas>
</body>
<script type="text/javascript" src="http://www.w3school.com.cn/jquery/jquery.js"></script>
<script type="text/javascript">
// 初始化Canvas
function init_canvas(canvas_id){
var canvas = document.getElementById("canvas");
canvas.width = 800;
canvas.height = 800;
return canvas.getContext("2d");
}
// 繪製線條公用方法
// context Canvas 容器 x y 起點 line_array 線條數組 line_width 線條精細 stroke_style 填充顏色
// line_width line_width 爲空即用默認值
function pub_ph(context, x_y, line_array, line_width, stroke_style){
context.moveTo(x_y[0], x_y[1]);
// 循環繪製線條
$.each(line_array, function(i, v){
//在第一次循環中，this代表一個一維數組，將這個一維數組再次送到each函數中，遍歷裏面的一維函數
context.lineTo(v[0], v[1]);
});
// 設置填充顏色
if(stroke_style != null)
context.strokeStyle = stroke_style;
// 設置線條顏色
if(line_width != null)
context.lineWidth = line_width;
context.stroke();
}
// |\
// ---- \
// ----| /
// |/
function ph1(context){
var line_array = [[100, 350], [500, 350], [500, 350] , [500, 200], [700, 400], [500, 600], [500, 450], [100, 450]];
pub_ph(context, [[100, 350]], line_array, 20, "#582");
}
// \ \ \
// / / /
function ph2(context){
context.beginPath();
context.moveTo(100, 200);
context.lineTo(300, 400);
context.lineTo(100, 600);
context.strokeStyle = "red";
context.stroke();
context.beginPath();
context.moveTo(300, 200);
context.lineTo(500, 400);
context.lineTo(300, 600);
context.strokeStyle = "green";
context.stroke();
context.beginPath();
context.moveTo(500, 200);
context.lineTo(700, 400);
context.lineTo(500, 600);
context.strokeStyle = "blue";
context.stroke();
}
// |\
// |--- \
// |---| /
// |/
function ph3(context){
context.moveTo(100, 350);
context.lineTo(500, 350);
context.lineTo(500, 350);
context.lineTo(500, 200);
context.lineTo(700, 400);
context.lineTo(500, 600);
context.lineTo(500, 450);
context.lineTo(100, 450);
context.lineTo(100, 350);
context.closePath();
context.lineWidth = "10";
context.strokeStyle = "#c00";
context.fillStyle = "#ff0"
//Canvas 基於狀態繪製，設置完繪製屬性進行繪製操作
context.fill();
context.stroke();
}
// _____
// | |
// |_____|
//
function ph4(context){
context.lineWidth = 5;
context.fillStyle = "#00f";
context.strokeStyle = "#f3c";
context.fillRect(200, 200, 400, 400);
context.strokeRect(200, 200, 400, 400);
}
// 五角星
function ph5(context){
context.beginPath();
for(var i = 0; i < 5; i++){
var x = Math.cos((18 + i * 72 - 30) / 180 * Math.PI) * 300 + 400;
var y = -Math.sin((18 + i * 72 - 30) / 180 * Math.PI) * 300 + 400;
context.lineTo(x, y);
x = Math.cos((54 + i * 72 - 30) / 180 * Math.PI) * 150 + 400;
y = -Math.sin((54 + i * 72 -30) / 180 * Math.PI) * 150 + 400;
context.lineTo(x, y);
}
context.closePath();
context.strokeStyle = "#f00";
context.fillStyle = "#f00";
context.lineWidth = 10;
context.fill();
context.stroke();
}
$(function(){
var context = init_canvas("canvas");
ph5(context);
});
</script>
</html>
最近在學習Html5 ，從最基礎的 Canvas 繪圖開始學習，分享一下二天下來的成果，效果圖：
