效果演示

1.左下点

2.左上点

3.上左点

var doc = activeDocument;
var pt = 72 / 25.4;
var cx = 3 * pt;

var marks = [];
for (var i = 0; i < doc.selection.length; i++) {
    var shape = doc.selection[i];
    if (shape.typename == 'GroupItem' && shape.pageItems.length > 0) {
        if (shape.clipped) {
            //这里蒙版的判断有点懵逼   下面应该能获取2层
            var sh = shape.pageItems[0];
            if (sh.pageItems && sh.pageItems.length > 0) {
                sh = sh.pageItems[0];
            }
            marks.push(sh)
        }
    }
}

var results = []
for (var i = 0; i < marks.length; i++) {
    results.push(checkShapeBounds(marks[i], marks,0.1));
}

for(var i=0;i<marks.length;i++){
    var result = results[i];
    new Main(marks[i],
        result.left, result.leftBottom, result.leftTop,
        result.top, result.topLeft, result.topRight,
        result.right, result.rightTop, result.rightBottom,
        result.bottom, result.bottomLeft, result.bottomRight
    ).work();
}


//判断 图形周围是不是有图形
function checkShapeBounds(shape, shapes, tolerance) {
    var result = {
        left: false,
        leftBottom:false,
        leftTop:false,
        top: false,
        topLeft: false,
        topRight: false,
        bottom: false,
        bottomLeft: false,
        bottomRight: false,
        right: false,
        rightTop: false,
        rightTopCount: 0,
        rightBottom: false,
    };
    var bounds = shape.geometricBounds;
    /**
     * 线重合
     */
    for (var i = 0; i < shapes.length; i++) {
        var otherShape = shapes[i];
        str+=otherShape.geometricBounds[0]+","+otherShape.geometricBounds[1]+","+otherShape.geometricBounds[2]+","+otherShape.geometricBounds[3]+"\n"
        if (otherShape === shape) {
            continue; // 跳过当前形状
        }
        var otherBounds = otherShape.geometricBounds;
        var leftLine = Math.abs(bounds[0] - otherBounds[0]) < tolerance;
        var rightLine = Math.abs(bounds[2] - otherBounds[2]) < tolerance;
        var topLine = Math.abs(bounds[1] - otherBounds[1]) < tolerance;
        var bottomLine = Math.abs(bounds[3] - otherBounds[3]) < tolerance;

        if(topLine && bottomLine){
            if ( Math.abs(otherBounds[2] - bounds[0]) < tolerance) {
                result.left = true;
            }
            if (Math.abs(otherBounds[0] - bounds[2]) < tolerance) {
                result.right = true;
            }
        }
        if(leftLine&&rightLine){
            if (Math.abs(otherBounds[3] - bounds[1]) < tolerance) {
                result.top = true;
            }
            if (Math.abs(otherBounds[1] - bounds[3]) < tolerance) {
                result.bottom = true;
            }
        }
    }
    /**
     * 线 三边是否有内容
     */
    for (var i = 0; i < shapes.length; i++) {
        var otherShape = shapes[i];
        if (otherShape === shape) {
            continue; // 跳过当前形状
        }
        var otherBounds = otherShape.geometricBounds;
        var left = Math.abs(otherBounds[2] - bounds[0]) < tolerance;
        var right = Math.abs(otherBounds[0] - bounds[2]) < tolerance;
        var bottom = Math.abs(otherBounds[1] - bounds[3]) < tolerance;
        var top = Math.abs(otherBounds[3] - bounds[1]) < tolerance;

        if(result.left&&left&&top){
            result.topLeft= true;
        }
        if(result.left&&left&&bottom){
            result.bottomLeft= true;
        }

        if(result.right&&right&&top){
            result.topRight= true;
        }
        if(result.right&&right&&bottom){
            result.bottomRight= true;
        }


        if(result.bottom&&bottom&&right){
            result.rightBottom= true;
        }
        if(result.bottom&&bottom&&left){
            result.leftBottom= true;
        }

        if(result.top&&top&&right){
            result.rightTop= true;
        }
        if(result.top&&top&&left){
            result.leftTop= true;
        }

    }
    result.left =!result.left;
    result.top =!result.top;
    result.bottom =!result.bottom;
    result.right =!result.right;
    return result;
}



/**
 * 下面是 7个 位置的 代码
 var main = new Main(shape, true, false, false, false, false, false, false, false, false, true, false, false).work();//1
 var main = new Main(shape, false, false, false, true, true, true, false, false, true, true, true, true).work();//2
 var main = new Main(shape, false, false, false, false, false, false, false, false, false, false, false, false).work();//3
 var main = new Main(shape, false, false, false, true, true, false, false, false, false, true, true, false).work();//4
 var main = new Main(shape, true, true, false, true, false, false, true, false, true, false, false, false).work();//5
 var main = new Main(shape, true, true, false, true, false, false, true, false, true, false, false, false).work();//6
 var main = new Main(shape, true, false, true, false, false, false, true, true, false, true, false, false).work();//7
 * @param shape
 * @param left
 * @param leftBottom
 * @param leftTop
 * @param top
 * @param topLeft
 * @param topRight
 * @param right
 * @param rightTop
 * @param rightBottom
 * @param bottom
 * @param bottomLeft
 * @param bottomRight
 * @constructor
 */
function Main(shape, left, leftBottom, leftTop, top, topLeft, topRight, right, rightTop, rightBottom, bottom, bottomLeft, bottomRight) {
    var rect = new Rect(shape.geometricBounds);
    this.left = left;
    this.leftTop = leftTop;
    this.leftBottom = leftBottom;
    this.top = top;
    this.topLeft = topLeft;
    this.topRight = topRight;
    this.right = right;
    this.rightBottom = rightBottom;
    this.rightTop = rightTop;
    this.bottom = bottom;
    this.bottomLeft = bottomLeft;
    this.bottomRight = bottomRight;
    this.x1 = rect.x1;
    this.y1 = rect.y1;
    this.x2 = rect.x2;
    this.y2 = rect.y2;
    this.paths = [];
    this.shape = shape;

    function computeNode() {
        //左下
        if (this.left) {
            if (this.leftBottom) {
                this.paths.push([this.x1, this.y1])
                this.paths.push([this.x1 - cx, this.y1 + cx])
            } else {
                if (this.bottom) {
                    if (!this.bottomLeft) {
                        this.paths.push([this.x1 - cx, this.y1 - cx])
                    }
                } else {
                    this.paths.push([this.x1 - cx, this.y1])
                }
            }
        } else {
            if (this.bottom && !this.bottomLeft) {
                this.paths.push([this.x1, this.y1 - cx])
            } else {
                this.paths.push([this.x1, this.y1])
            }

        }
        //左上
        if (this.left) {
            if (this.leftTop) {
                this.paths.push([this.x1 - cx, this.y2 - cx])
                this.paths.push([this.x1, this.y2])
            } else {
                if (this.top) {
                    if (!this.topLeft) {
                        this.paths.push([this.x1 - cx, this.y2 + cx])
                    }
                } else {
                    this.paths.push([this.x1 - cx, this.y2])
                }
            }
        } else {
            if (this.top && !this.topLeft) {
                this.paths.push([this.x1, this.y2 + cx])
            } else {
                this.paths.push([this.x1, this.y2])
            }

        }
        //上左
        if (this.top) {
            if (this.topLeft) {
                this.paths.push([this.x1, this.y2])
                this.paths.push([this.x1 + cx, this.y2 + cx])

            } else {
                if (this.left) {
                    if (!this.leftTop) {
                        this.paths.push([this.x1 - cx, this.y2 + cx])
                    }
                } else {
                    this.paths.push([this.x1, this.y2 + cx])
                }
            }
        } else {
            if (this.left && !this.leftTop) {
                this.paths.push([this.x1 - cx, this.y2])
            } else {
                this.paths.push([this.x1, this.y2])
            }

        }
        //上右
        if (this.top) {
            if (this.topRight) {
                this.paths.push([this.x2 - cx, this.y2 + cx])
                this.paths.push([this.x2, this.y2])
            } else {
                if (this.right) {
                    if (!this.rightTop) {
                        this.paths.push([this.x2 + cx, this.y2 + cx])
                    }
                } else {
                    this.paths.push([this.x2, this.y2 + cx])
                }
            }
        } else {
            if (this.right && !this.rightTop) {
                this.paths.push([this.x2 + cx, this.y2])
            } else {
                this.paths.push([this.x2, this.y2])
            }

        }

        //右上
        if (this.right) {
            if (this.rightTop) {
                this.paths.push([this.x2, this.y2])
                this.paths.push([this.x2 + cx, this.y2 - cx])

            } else {
                if (this.top) {
                    if (!this.topRight) {
                        this.paths.push([this.x2 + cx, this.y2 + cx])
                    }
                } else {
                    this.paths.push([this.x2 + cx, this.y2])
                }
            }
        } else {
            if (this.top && !this.topRight) {
                this.paths.push([this.x2, this.y2 + cx])
            } else {
                this.paths.push([this.x2, this.y2])
            }

        }

        //右下
        if (this.right) {
            if (this.rightBottom) {
                this.paths.push([this.x2 + cx, this.y1 + cx])
                this.paths.push([this.x2, this.y1])
            } else {
                if (this.bottom) {
                    if (!this.bottomRight) {
                        this.paths.push([this.x2 + cx, this.y1 - cx])
                    }
                } else {
                    this.paths.push([this.x2 + cx, this.y1])
                }
            }
        } else {
            if (this.bottom && !this.bottomRight) {
                this.paths.push([this.x2, this.y1 - cx])
            } else {
                this.paths.push([this.x2, this.y1])
            }

        }

        //下右
        if (this.bottom) {
            if (this.bottomRight) {
                this.paths.push([this.x2, this.y1])
                this.paths.push([this.x2 - cx, this.y1 - cx])

            } else {
                if (this.right) {
                    if (!this.rightBottom) {
                        this.paths.push([this.x2 + cx, this.y1 - cx])
                    }
                } else {
                    this.paths.push([this.x2, this.y1 - cx])
                }
            }
        } else {
            if (this.right && !this.rightBottom) {
                this.paths.push([this.x2 + cx, this.y1])
            } else {
                this.paths.push([this.x2, this.y1])
            }

        }

        //下左
        if (this.bottom) {
            if (this.bottomLeft) {
                this.paths.push([this.x1 + cx, this.y1 - cx])
                this.paths.push([this.x1, this.y1])
            } else {
                if (this.left) {
                    if (!this.leftBottom) {
                        this.paths.push([this.x1 - cx, this.y1 - cx])
                    }
                } else {
                    this.paths.push([this.x1, this.y1 - cx])
                }
            }
        } else {
            if (this.left && !this.leftBottom) {
                this.paths.push([this.x1 - cx, this.y1])
            } else {
                this.paths.push([this.x1, this.y1])
            }
        }
    }

    function addNodesToMask() {
// 添加节点到其他节点上
        for (var i = sh.pathPoints.length; i < this.paths.length; i++) {
            this.shape.pathPoints.add();
        }
        //修改节点的坐标
        for (var i = 0; i < this.paths.length; i++) {
            this.shape.pathPoints[i].anchor = this.paths[i];
            this.shape.pathPoints[i].leftDirection = this.paths[i];
            this.shape.pathPoints[i].rightDirection = this.paths[i];
        }
    }

    this.work = function () {
        computeNode.call(this);
        addNodesToMask.call(this);
    }
    function Rect(bounds) {
        this.x1 = bounds[0];
        this.y1 = bounds[3];
        this.x2 = bounds[2];
        this.y2 = bounds[1];
    }
}