using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;

namespace AIStudio.Wpf.DiagramDesigner
{
    /// <summary>
    /// 获取当前光标处颜色，win8下wpf测试成功
    /// </summary>
    public class ColorPickerManager
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="x">鼠标相对于显示器的坐标X</param>
        /// <param name="y">鼠标相对于显示器的坐标Y</param>
        /// <returns></returns>
        //public static System.Drawing.Color GetColor(int x, int y)
        //{
        //    IntPtr hdc = GetDC(IntPtr.Zero);
        //    uint pixel = GetPixel(hdc, x, y);
        //    ReleaseDC(IntPtr.Zero, hdc);
        //    System.Drawing.Color color = System.Drawing.Color.FromArgb((int)(pixel & 0x000000FF), (int)(pixel & 0x0000FF00) >> 8, (int)(pixel & 0x00FF0000) >> 16);

        //    return color;
        //}

        /// <summary>
        /// 
        /// </summary>
        /// <param name="x">鼠标相对于显示器的坐标X</param>
        /// <param name="y">鼠标相对于显示器的坐标Y</param>
        /// <returns></returns>
        public static System.Windows.Media.Color GetColor(int x, int y)
        {
            IntPtr hdc = GetDC(IntPtr.Zero);
            uint pixel = GetPixel(hdc, x, y);
            ReleaseDC(IntPtr.Zero, hdc);
            System.Windows.Media.Color color = System.Windows.Media.Color.FromRgb((byte)(pixel & 0x000000FF), (byte)((pixel & 0x0000FF00) >> 8), (byte)((pixel & 0x00FF0000) >> 16));

            return color;
        }       

        [DllImport("gdi32.dll")]
        private static extern bool BitBlt(
        IntPtr hdcDest, // 目标设备的句柄 
        int nXDest, // 目标对象的左上角的X坐标 
        int nYDest, // 目标对象的左上角的X坐标 
        int nWidth, // 目标对象的矩形的宽度 
        int nHeight, // 目标对象的矩形的长度 
        IntPtr hdcSrc, // 源设备的句柄 
        int nXSrc, // 源对象的左上角的X坐标 
        int nYSrc, // 源对象的左上角的X坐标 
        int dwRop // 光栅的操作值 
        );

        [DllImport("gdi32.dll")]
        private static extern IntPtr CreateDC(
        string lpszDriver, // 驱动名称 
        string lpszDevice, // 设备名称 
        string lpszOutput, // 无用，可以设定位"NULL" 
        IntPtr lpInitData // 任意的打印机数据 
        );

        /// <summary>
        /// 获取指定窗口的设备场景
        /// </summary>
        /// <param name="hwnd">将获取其设备场景的窗口的句柄。若为0，则要获取整个屏幕的DC</param>
        /// <returns>指定窗口的设备场景句柄，出错则为0</returns>
        [DllImport("user32.dll")]
        private static extern IntPtr GetDC(IntPtr hwnd);

        /// <summary>
        /// 释放由调用GetDC函数获取的指定设备场景
        /// </summary>
        /// <param name="hwnd">要释放的设备场景相关的窗口句柄</param>
        /// <param name="hdc">要释放的设备场景句柄</param>
        /// <returns>执行成功为1，否则为0</returns>
        [DllImport("user32.dll")]
        private static extern Int32 ReleaseDC(IntPtr hwnd, IntPtr hdc);

        /// <summary>
        /// 在指定的设备场景中取得一个像素的RGB值
        /// </summary>
        /// <param name="hdc">一个设备场景的句柄</param>
        /// <param name="nXPos">逻辑坐标中要检查的横坐标</param>
        /// <param name="nYPos">逻辑坐标中要检查的纵坐标</param>
        /// <returns>指定点的颜色</returns>
        [DllImport("gdi32.dll")]
        private static extern uint GetPixel(IntPtr hdc, int nXPos, int nYPos);
    }
}