官术网_书友最值得收藏!

Working with text

Almost all applications require some sort of text to effectively communicate something to the user. This recipe will show you how to draw a simple text string with an optimistic welcoming.

Working with text

How to do it...

Follow these steps to write text on the canvas:

  1. Define a 2D canvas context and set the text style:
    window.onload = function(){
        var canvas = document.getElementById("myCanvas");
        var context = canvas.getContext("2d");
        
        context.font = "40pt Calibri";
        context.fillStyle = "black";
  2. Horizontally and vertically align the text, and then draw it:
    // align text horizontally center
        context.textAlign = "center";
        // align text vertically center
        context.textBaseline = "middle";
        context.fillText("Hello World!", canvas.width / 2, 120);
    };
  3. Embed the canvas tag inside the body of the HTML document:
    <canvas id="myCanvas" width="600" height="250" style="border:1px solid black;">
    </canvas>

How it works...

To draw text with the HTML5 canvas, we can define the font style and size with the font property, the font color with the fillStyle property, the horizontal text alignment with the textAlign property, and the vertical text alignment with the textBaseline property. The textAlign property can be set to left, center, or right, and the textBaseline property can be set to top, hanging, middle, alphabetic, ideographic, or bottom. Unless otherwise specified, the textAlign property is defaulted to left, and the textBaseline property is defaulted to alphabetic.

There's more...

In addition to fillText(), the HTML5 canvas API also supports strokeText():

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

This method will color the perimeter of the text instead of filling it. To set both the fill and stroke for HTML canvas text, you can use both the fillText() and the strokeText() methods together. It's good practice to use the fillText() method before the strokeText() method in order to render the stroke thickness correctly.

See also...

  • Drawing 3D text with shadows
  • Creating a mirror transform in Chapter 4
  • Drawing a simple logo and randomizing its position, rotation, and scale in Chapter 4
主站蜘蛛池模板: 泉州市| 安达市| 马关县| 华亭县| 西宁市| 定南县| 南汇区| 渑池县| 宁明县| 海丰县| 和静县| 定边县| 南皮县| 大悟县| 秦安县| 玉门市| 浪卡子县| 彰化市| 廊坊市| 赣州市| 邢台县| 资溪县| 绥棱县| 麻城市| 剑川县| 林周县| 通江县| 延津县| 明水县| 财经| 阜新| 凤山县| 榆中县| 普格县| 广丰县| 扎赉特旗| 沧州市| 迁安市| 凌云县| 汕头市| 南乐县|