PDF_Office/PDF Office/PDF Master/Class/Batch/Catogary/NSButton+CustomAppearance.swift

//
//  NSButton+CustomAppearance.swift
//  PDF Reader Pro
//
//  Created by kdanmobile on 2023/10/26.
//

import Foundation

let NSButtonAddHoverKey = "NSButtonAddHoverKey"
let NSButtonTrackingAreaKey = "NSButtonTrackingAreaKey"
var placeholderImage: NSImage?

extension NSButton{
    var addHoverEffect: Bool {
        get {
            return (objc_getAssociatedObject(self, NSButtonAddHoverKey) as? NSNumber)?.boolValue ?? false
        }
        set {
            removeTrackingArea(self.neededTrackingArea ?? NSTrackingArea())
            if newValue {
                addNewTrackingArea()
            }
            objc_setAssociatedObject(self, NSButtonAddHoverKey, NSNumber(value: newValue), .OBJC_ASSOCIATION_RETAIN)
        }
    }
    var neededTrackingArea: NSTrackingArea? {
        get {
            return objc_getAssociatedObject(self, NSButtonTrackingAreaKey) as? NSTrackingArea
        }
        set {
            objc_setAssociatedObject(self, NSButtonTrackingAreaKey, newValue, .OBJC_ASSOCIATION_RETAIN)
        }
    }
    func addNewTrackingArea() {
        self.wantsLayer = true
        let trackingArea = NSTrackingArea(rect: self.bounds, options: [.mouseEnteredAndExited, .inVisibleRect, .activeAlways], owner: self, userInfo: nil)
        self.addTrackingArea(trackingArea)
        self.neededTrackingArea = trackingArea
    }
    open override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        if self.addHoverEffect {
            if !self.isEnabled {
                return
            }
            if (self.image != nil) && (self.alternateImage != nil) {
                self.alternateImage = self.image
                self.image = placeholderImage
            }
        }
    }
    
    open override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        if self.addHoverEffect {
            if !self.isEnabled {
                return
            }
            if (self.image != nil) && (self.alternateImage != nil) {
                placeholderImage = self.image
                self.image = self.alternateImage
            }
        }
    }
}