html5 canvas drawing rectangle and circle example code
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> </head> <body onload="draw(),drawarc()"> <!--绘制的步骤:获取canvas元素->取得上下文->填充与绘制边框->设定绘图样式--> <!--绘制其他复杂图形需要使用路径:开始创建路径->创建图形路径->关闭路径->绘制图形--> <!--eg:绘制矩形--> 绘制矩形:<canvas id="ca"></canvas><br /> 绘制圆形:<canvas id="yuan"></canvas> </body> </html> <script> //绘制矩形 function draw(){ var canvas=document.getElementById('ca'); //获取canvas元素 if (canvas==null) return false; var context=canvas.getContext('2d'); //取得上下文 context.fillStyle='#EEEFF'; //填充颜色 context.fillRect(0,0,400,300); //填充矩形 (矩形1) context.fillStyle='red'; context.strokeStyle='blue'; //边框颜色 context.lineWidth=1; //边框宽度 context.fillRect(50,50,100,100); //填充矩形(内部矩形2) context.strokeRect(50,50,100,100); //绘制边框 } //绘制圆形 function drawarc(){ var canvas2=document.getElementById('yuan'); //获取canvas元素 if (canvas2==null) if(canvas2==null) return false; var context2=canvas2.getContext('2d'); //取得上下文 context2.fillStyle='#EEEEEF'; context2.fillRect(0,0,400,300); var n=0; for(var i=0;i<10;i++){ context2.beginPath(); //开始创建路径 context2.arc(i*25,i*25,i*10,0,Math.PI*2,true); //创建圆形路径 context2.closePath(); //关闭路径 context2.fillStyle='Rgba(255,0,0,0.25)'; //设置颜色 context2.fill(); //填充图形 } } </script>