.img() parameters about g2 HOT 3 CLOSED

mec.shape.img = {
    /**
     * Check image shape properties for validity.
     * @method
     * @param {number} idx - index in shape array.
     * @returns {boolean} false - if no error / warning was detected. 
     */
    validate(idx) {
        if (this.uri === undefined) 
            return { mid:'E_IMG_URI_MISSING',id:this.id,idx};

        if (this.p === undefined) 
            return { mid:'E_ELEM_REF_MISSING',elemtype:'image',id:this.id,idx,reftype:'node',name:'p'};
        if (!this.model.nodeById(this.p)) 
            return { mid:'E_ELEM_INVALID_REF',elemtype:'image',id:this.id,idx,reftype:'node',name:this.p};
        else
            this.p = this.model.nodeById(this.p);

        if (this.wref && !this.model.constraintById(this.wref)) 
            return { mid:'E_ELEM_INVALID_REF',elemtype:'image',id:this.id,idx,reftype:'constraint',name:this.wref};
        else
            this.wref = this.model.constraintById(this.wref);

        return false;
    },
    /**
     * Initialize polygon shape. Multiple initialization allowed.
     * @method
     * @param {object} model - model parent.
     * @param {number} idx - index in shapes array.
     */
    init(model,idx) {
        this.model = model;
        if (!this.model.notifyValid(this.validate(idx))) return;

        this.w0 = this.w0 || 0;
        this.b = this.b || 100;
        this.h = this.h || 100;
        this.xoff = this.xoff || 0;
        this.yoff = this.yoff || 0;
        this.scl = this.scl || 5;
    },
    dependsOn(elem) {
        return this.p === elem || this.wref === elem;
    },
    asJSON() {
        return '{ "type":"'+this.type+'","uri":"'+this.uri+'","p":"'+this.p.id+'"'
                + (this.wref ? ',"wref":"'+this.wref.id+'"' : '')
                + ((this.w0 && this.w0 > 0.0001) ? ',"w0":'+this.w0 : '')
                + ((this.b && Math.abs(this.b - 100) > 0.01) ? ',"b":'+this.b : '')
                + ((this.h && Math.abs(this.h - 100) > 0.01) ? ',"h":'+this.h : '')
                + ((this.xoff && Math.abs(this.xoff) > 0.0001) ? ',"xoff":'+this.xoff : '')
                + ((this.yoff && Math.abs(this.yoff) > 0.0001) ? ',"yoff":'+this.yoff : '')
                + ((this.scl && Math.abs(this.scl - 1) > 0.0001) ? ',"scl":'+this.scl : '')
                + ' }';
    },
    draw(g) {
        const w0 = this.w0 || 0, w = this.wref ? ()=>this.wref.w + w0 : w0;
        g.img({uri:this.uri,x:()=>this.p.x,y:()=>this.p.y,w,b:this.b,h:this.h,scl:this.scl,xoff:this.xoff,yoff:this.yoff})
    }
}