Book Image

TypeScript Blueprints

By : Ivo Gabe de Wolff
Book Image

TypeScript Blueprints

By: Ivo Gabe de Wolff

Overview of this book

TypeScript is the future of JavaScript. Having been designed for the development of large applications, it is now being widely incorporated in cutting-edge projects such as Angular 2. Adopting TypeScript results in more robust software - software that is more scalable and performant. It's scale and performance that lies at the heart of every project that features in this book. The lessons learned throughout this book will arm you with everything you need to build some truly amazing projects. You'll build a complete single page app with Angular 2, create a neat mobile app using NativeScript, and even build a Pac Man game with TypeScript. As if fun wasn't enough, you'll also find out how to migrate your legacy codebase from JavaScript to TypeScript. This book isn't just for developers who want to learn - it's for developers who want to develop. So dive in and get started on these TypeScript projects.
Table of Contents (16 chapters)
TypeScript Blueprints
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Drawing on the canvas


In lib/framework/draw.ts, we will implement the drawPicture function that we created before. Using instanceof we can check which kind of picture we must draw.

We will interpret the location of an object as the center of it. Thus, new Rectangle(10, 10, 100, 100) will draw a rectangle around 10,10. We can draw the outline of a rectangle or the whole rectangle with strokeRect and fillRect:

import { Picture, Rectangle, RectangleOutline, Circle, CircleOutline, Line, Text, Color, Translate, Rotate, Scale, Pictures, Path } from "./picture"; 
 
export function drawPicture(context: CanvasRenderingContext2D, item: Picture) { 
  context.save(); 
  if (item instanceof RectangleOutline) { 
    const { x, y, width, height, thickness } = item; 
    context.strokeRect(x - width / 2, y - height / 2, width, height); 
  } else if (item instanceof Rectangle) { 
    const { x, y, width, height } = item; 
    context.fillRect(x - width / 2, y -...