using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace videoGather
{
    public class DoubleBufferedPanel : Panel
    {

        private Bitmap _backImage;
        // 新增背景图属性
        public Bitmap BackImage
        {
            get => _backImage;
            set
            {
                if (_backImage != null)
                {
                    _backImage.Dispose();
                }
                _backImage = value;
                Invalidate(); // 触发重绘
            }
        }
        // 构造函数
        public DoubleBufferedPanel()
        {
            // 启用双缓冲
            this.DoubleBuffered = true; // 内置支持
                                        // 设置样式以避免闪烁
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer |
                          ControlStyles.AllPaintingInWmPaint |
                          ControlStyles.UserPaint, true);
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
            // 禁用默认背景绘制（关键！）
            // base.OnPaintBackground(e);  // 注释掉这行
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            // 绘制自定义背景图
            if (_backImage != null)
            {
                e.Graphics.DrawImage(_backImage, ClientRectangle);
            }

            base.OnPaint(e); // 保持原有绘制逻辑
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _backImage?.Dispose();
            }
            base.Dispose(disposing);
        }
    }
}