垂直对齐，使用CSS很容易实现，如果想在HTML5 Canvas中实现垂直对齐，如何设置呢，这就是今天要分享的笔记。

HTML画布垂直对齐的文本，我们可以使用的textBaseline在画布范围内的属性值。textBaseline可以设置以下值之一 ：top, hanging, middle, alphabetic, ideographic, and bottom。除非另有规定，textBaseline属性默认为字母。

context.textBaseline=[value];

html5_canvas_text_baseline

body {margin: 0px;padding: 0px;}

#myCanvas {border: 1px solid #9C9898; margin:0 auto;margin-top:200px; margin-left:100px;}

window.onload = function(){

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

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

var x = canvas.width / 2;

var y = canvas.height / 2;

context.font = "30pt Calibri";

// textAlign aligns text horizontally relative to placement

context.textAlign = "center";

// textBaseline aligns text vertically relative to font style

context.textBaseline = "middle";

context.fillStyle = "blue";

context.fillText("Hello World!", x, y);

};