How to add image to Path in PaperJS

问题

I am playing around with the nice code from http://paperjs.org/examples/candy-crash/. I want to replace the colors with an image so that instead of showing say a red circle, it should show a circle with an image inside. Here is the snippet I think I need to modify:

function Ball(r, p, v) {
    this.radius = r;
    this.point = p;
    this.vector = v;
    this.maxVec = 15;
    this.numSegment = Math.floor(r / 3 + 2);
    this.boundOffset = [];
    this.boundOffsetBuff = [];
    this.sidePoints = [];
    this.path = new Path({
        fillColor: {
            hue: Math.random() * 360,
            saturation: 1,
            brightness: 1
        },
        blendMode: 'screen'
    });

    for (var i = 0; i < this.numSegment; i ++) {
        this.boundOffset.push(this.radius);
        this.boundOffsetBuff.push(this.radius);
        this.path.add(new Point());
        this.sidePoints.push(new Point({
            angle: 360 / this.numSegment * i,
            length: 1
        }));
    }
}

I am reading up on raster as well. But I don't see how to get this code to work with the image. Thanks for any help.

If I simply do this.path = new Path(raster) it does not work. It only shows one static image as opposed to all the circles moving around.

UPDATE

Here is a raster to use

var imgUrl ="http://upload.wikimedia.org/wikipedia/commons/1/15/Red_Apple.jpg";
var raster = new Raster();
raster.scale(0.2)

回答1:

If you want to clip a raster with a path, you need to create a group that contains both objects, then set group.clipped property to true. Passing a raster as the argument for a path constructor will not work.

It's easiest to do this in the "main" loop.

//--------------------- main ---------------------

var balls = [];

// ADD AN ARRAY TO HOLD SOME RASTERS

var rasters = [];
var raster = new Raster("http://upload.wikimedia.org/wikipedia/commons/1/15/Red_Apple.jpg");
raster.scale(.05);
var numBalls = 18;
for (var i = 0; i < numBalls; i++) {
    var position = Point.random() * view.size;
    var vector = new Point({
        angle: 360 * Math.random(),
        length: Math.random() * 10
    });
    var radius = Math.random() * 60 + 60;
    balls.push(new Ball(radius, position, vector));

    // ADD RASTERS AND CLIP TO EACH "BALL"

    rasters.push(raster.clone().scale(radius/50));
    var group = new Group(balls[i].path, rasters[i]);
    group.clipped = true;
}
raster.remove();

function onFrame() {
    for (var i = 0; i < balls.length - 1; i++) {
        for (var j = i + 1; j < balls.length; j++) {
            balls[i].react(balls[j]);
        }
    }
    for (var i = 0, l = balls.length; i < l; i++) {
        balls[i].iterate();
        rasters[i].position = balls[i].path.position;
    }
}

来源：https://stackoverflow.com/questions/27428726/how-to-add-image-to-path-in-paperjs

标签

javascript

html5

image

vector-graphics

paperjs