     if (maskCenterB - maskCenterT >= centerCheckSize) {
                        const delta = (maskCenterB - maskCenterT - centerCheckSize) / 2;
                        maskCenterT += delta;
                        maskCenterB -= delta;
                    }

                    const possiblePosArr = [];
                    const maskColors = frontContext.getImageData(maskCenterL, maskCenterT, maskCenterR - maskCenterL, maskCenterB - maskCenterT).data;
                    for (let alpha = 0.3; alpha <= 0.