HTML5 canvas basic drawing text rendering

var canvas = document.getElementById("canvas");   

        var context = canvas.getContext("2d");   

      

        context.font="bold 30px Arial"; //设置样式   

        context.strokeStyle = "#1712F4";   

        context.strokeText("欢迎来到我的博客！",30,100);   

      

        context.font="bold 50px Arial";    

        var grd = context.createLinearGradient( 30 , 200, 400 , 300 );//设置渐变填充样式   

        grd.addColorStop(0,"#1EF9F7");   

        grd.addColorStop(0.25,"#FC0F31");   

        grd.addColorStop(0.5,"#ECF811");   

        grd.addColorStop(0.75,"#2F0AF1");   

        grd.addColorStop(1,"#160303");   

        context.fillStyle = grd;   

        context.fillText("欢迎来到我的博客！",30,200);   

      

        context.save();   

        context.moveTo(200,280);   

        context.lineTo(200,420);   

        context.stroke();   

        context.font="bold 20px Arial";    

        context.fillStyle = "#F80707";   

        context.textAlign="left";   

        context.fillText("文本在指定的位置开始",200,300);   

        context.textAlign="center";   

        context.fillText("文本的中心被放置在指定的位置",200,350);   

        context.textAlign="right";   

        context.fillText("文本在指定的位置结束",200,400);   

        context.restore();   

      

        context.save();   

        context.moveTo(10,500);   

        context.lineTo(500,500);   

        context.stroke();   

        context.fillStyle="#F60D0D";   

        context.font="bold 20px Arial";    

        context.textBaseline="top";   

        context.fillText("指定位置在上面",10,500);   

        context.textBaseline="bottom";   

        context.fillText("指定位置在下面",150,500);   

        context.textBaseline="middle";   

        context.fillText("指定位置居中",300,500);   

        context.restore();   

      

      

        context.font="bold 40px Arial";    

        context.strokeStyle = "#16F643";   

        var text = "欢迎来到我的博客！";   

        context.strokeText("欢迎来到我的博客！",10,600);   

        context.strokeText("上面字符串的宽度为："+context.measureText(text).width,10,650);