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Canvas Cookbook

You're reading from   Canvas Cookbook Over 80 simple but creative and structured recipes to explore the capabilities of HTML5 Canvas

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Product type Paperback
Published in May 2019
Publisher
ISBN-13 9781785284892
Length 254 pages
Edition 1st Edition
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Concepts
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Toc

Table of Contents (11) Chapters Close

Preface 1. Paths and Text 2. Shapes and Composites FREE CHAPTER 3. Animation 4. Images and Videos 5. Interactivity through Events 6. Creating Graphs and Charts 7. 3D Modeling 8. Game Development 9. Interoperability and Deployment Index

Drawing triangles


There is no direct function to draw a triangle using the canvas API. But we do have the other, simpler functions that, together, allow us to draw different shapes. A triangle is a combination of three joined lines. Let's see this in our new example. The output is quite simple and looks like this:

How to do it…

The triangle is drawn by calling two basic functions, namely moveTo() and lineTo(). Here is the recipe.

The HTML file:

<html>
<head>
<title>triangles</title>
<script src="triangles.js"></script>
</head>
<body onload="init()">
<canvas id="MyCanvasArea" width="200" height="200" style="border:2px solid blue;" >
      your browser does not support canvas
</canvas>
<H1>Triangle</H1>
</body>
</html>

The JavaScript file:

function init(){
  var can = document.getElementById("MyCanvasArea");
  if(can.getContext)
  {
    var context=can.getContext("2d");  
    drawTriangle(context,100,20,100,100,...
You have been reading a chapter from
Canvas Cookbook
Published in: May 2019
Publisher:
ISBN-13: 9781785284892
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