Question

I have an image i need to rotate to an angle then draw it to the canvas at a point. I currently have this:

var image = roach.image;
image.style.msTransform = 'rotate(' + roach.heading + 'deg)';
this.gameContext.drawImage(image, roach.position.x, roach.position.y);

How can i edit this to make it work, where roach.heading is my angle i want to rotate it to in degrees.

Answer 1

Try this:

var image = roach.image,
    ctx = this.gameContext,
    widthHalf = Math.floor( image.width / 2 ),
    heightHalf = Math.floor( image.height / 2 );

ctx.save();

ctx.translate( roach.position.x, roach.position.y );
ctx.translate( widthHalf, heightHalf );
ctx.rotate( ( Math.PI / 180 ) * roach.heading );
ctx.drawImage( image, -widthHalf, -heightHalf );
ctx.restore();

jsfiddle: http://jsfiddle.net/PwzEc/