The Essential Guide to HTML5

CHAPTER 4

Code Explanation

ctx.lineTo(this.s2x,this.s2y); Set up to draw to s2x,s2y

ctx.lineTo(this.s3x,this.s3y); Draw to s3x,s3y

ctx.stroke(); Now draw the path

} Close function

function movesling(dx,dy) { Header for movesling

this.bx +=dx; Add dx to bx

this.by +=dy; Add dy to by

this.s1x +=dx; Add dx to slx

this.s1y +=dy; Add dy to s1y

this.s2x +=dx; Add dx to s2x

this.s2y +=dy; Add dy to s2y

this.s3x +=dx; Add dx to s3x

this.s3y +=dy; Add dy to s3y

} Close function

var mysling= new
Sling(startrockx,startrocky,

startrockx+80,startrocky-10,startrockx+80,

startrocky+10,startrockx+70,

startrocky+180,"rgb(120,20,10)");

Build new Sling and assign it to the mysling

variable

function Ball(sx,sy,rad,stylestring) {

this.sx = sx;

this.sy = sy;

this.rad = rad;

this.draw = drawball;