缩放 Matter.js canvas 打破鼠标拖动

Question

我的问题是：

我使用 Matter.js 在 canvas 上创建了一个可拖动对象。但是，当我缩放 canvas 时，我的鼠标点击不再拖动对象，因为点击因缩放而计算错误。 Matter.js 仍然认为 canvas 没有缩放。所以我必须在对象旁边单击才能真正拖动它。而且我缩放的越多，我必须从对象上点击越多。我需要做什么才能更正 Matter.js canvas 已缩放？

<body>
    <script>
        let Engine = Matter.Engine,
        Render = Matter.Render,
        World = Matter.World,
        Bodies = Matter.Bodies;

        let engine = Engine.create();
        let render = Render.create({
            element: document.body,
            engine: engine
        });

        Engine.run(engine);
        Render.run(render);
            

        let floor = Bodies.rectangle(0, 500, 600, 10, { isStatic: true });
        let ball = Bodies.circle(200, 10, 40);
        World.add(engine.world, [ball, floor]);


        render.canvas.width = 1000;
        render.canvas.height = 800;

        render.canvas.style.transformOrigin = '0 0';
        render.canvas.style.transform = 'scale(.8)';

        let world = engine.world;
        let Mouse = Matter.Mouse;
        let MouseConstraint = Matter.MouseConstraint;
        let mouse = Mouse.create(render.canvas);
        let mouseConstraint = MouseConstraint.create(engine, { mouse: mouse });
        World.add(world, mouseConstraint);
        render.mouse = mouse;
    </script>
</body>

亲切的问候，Slawek

Answer 1

感谢 ggorlen，答案是：

使用Matter.Mouse.setScale(鼠标、缩放);

您需要提供正确的比例尺，但您怎么知道只有初始比例尺用于缩放 canvas？公式如下：

set scale(scale){
        
    let mouseScale = 1 + (1 / (scale / (1 - scale)))
        
    this.Mouse.setScale(this.mouse, {x: mouseScale, y: mouseScale});
}

缩放 Matter.js canvas 打破鼠标拖动

Scaling Matter.js canvas breaks mouse drag

mouse

scaling

canvas

matter.js