There are some performance issues when use mask/effect...

[wanqingrongruo]

we should not handle mask/effect by this way:

func renderToImage(bounds: Rect, inset: Double = 0, coloringMode: ColoringMode = .rgb) -> MImage? {
        let screenScale: CGFloat = MMainScreen()?.mScale ?? 1.0
        MGraphicsBeginImageContextWithOptions(CGSize(width: bounds.w + inset, height: bounds.h + inset), false, screenScale)
        let tempContext = MGraphicsGetCurrentContext()!

        // flip y-axis and leave space for the blur
        tempContext.translateBy(x: CGFloat(inset / 2 - bounds.x), y: CGFloat(bounds.h + inset / 2 + bounds.y))
        tempContext.scaleBy(x: 1, y: -1)
        directRender(in: tempContext, force: false, opacity: 1.0, coloringMode: coloringMode)

        let img = MGraphicsGetImageFromCurrentImageContext()
        MGraphicsEndImageContext()
        return img
    }

when we have many effects,mask, us operations would get stuck... Image processing is very consumptive performance.