PDF_Office/PDF Office/PDF Master/KMClass/KMNPDFPageEdit/KMNThumbnailView/KMNCustomCollectionViewLayout.swift

//
//  KMNCustomCollectionViewLayout.swift
//  PDF Reader Pro
//
//  Created by 丁林圭 on 2024/11/9.
//

import Cocoa

class KMNThumCustomCollectionViewFlowLayout: NSCollectionViewFlowLayout {
    var lineAttributes: NSCollectionViewLayoutAttributes?
    var lineColor: NSColor = .systemBlue
    var lineHeight: CGFloat = 4.0
    
    override func layoutAttributesForElements(in rect: NSRect) -> [NSCollectionViewLayoutAttributes] {
        var attributes = super.layoutAttributesForElements(in: rect)
        
        // 将指示线添加到布局属性中
        if let lineAttributes = lineAttributes {
            attributes.append(lineAttributes)
        }
        
        return attributes
    }
    
    func showLine(at indexPath: IndexPath, below rect: NSRect) {
        let lineAttributes = NSCollectionViewLayoutAttributes(forDecorationViewOfKind: NSUserInterfaceItemIdentifier("Line").rawValue, with: indexPath)

        lineAttributes.frame = NSRect(x: rect.origin.x, y: rect.origin.y, width: rect.width, height: lineHeight)
        self.lineAttributes = lineAttributes
        invalidateLayout()
    }
    
    func hideLine() {
        lineAttributes = nil
        invalidateLayout()
    }
}