问HTML5旋转方法倾斜图像

EN

function Sprite(imgg,w,h)
{
    this.img = imgg;
    this.x = 350;//Math.random()*700;
    this.y = 350;//Math.random()*700;
    this.vx = 0;//Math.random()*8-4;
    this.vy = 0;//Math.random()*8-4;
    this.width = w;
    this.height = h;
    this.rotatespeed = 0;//0.01;
    this.rotate = 40;

}

function drawSprite(sprite, ctx)
{

    ctx.save();

    ctx.translate(sprite.x,sprite.y);
    ctx.rotate(sprite.rotate);


    ctx.drawImage(sprite.img,0,0,sprite.img.width,sprite.img.height,-sprite.width/2,-sprite.height,sprite.width,sprite.height);


    ctx.restore();
}

function drawGame(g)
{
    var gameLoop = setInterval(function(){

        g.context.clearRect(0,0,g.canvas.width, g.canvas.height);
        g.context.save();


        g.context.translate(g.canvas.width/2, g.canvas.height/2);
        g.context.scale(g.camera.scale,g.camera.scale);
        g.context.rotate(g.camera.rotate);
        g.context.translate(g.camera.x,g.camera.y);


        for(var i=0;i<g.objects.length;i++)
        {
            updateSprite(g.objects[i]);
            drawSprite(g.objects[i], g.context);
        }
        g.context.restore();

    },setIntervalAmount); 

}