C#獲取指定座標點像素，效率更高快

實際使用

Color actualcolor = pointBitmap.GetPixel(nowx, nowy);
if (actualcolor.R < 20 && actualcolor.G < 20 && actualcolor.B < 20)//黑點
{

}

類庫PointBitmap

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DianZhen
{
    public class PointBitmap
    {
        Bitmap source = null;
        IntPtr Iptr = IntPtr.Zero;
        BitmapData bitmapData = null;

        public int Depth { get; private set; }
        public int Width { get; private set; }
        public int Height { get; private set; }

        public PointBitmap(Bitmap source)
        {
            this.source = source;
        }

        public void LockBits()
        {
            try
            {
                // Get width and height of bitmap
                Width = source.Width;
                Height = source.Height;

                // get total locked pixels count
                int PixelCount = Width * Height;

                // Create rectangle to lock
                Rectangle rect = new Rectangle(0, 0, Width, Height);

                // get source bitmap pixel format size
                Depth = System.Drawing.Bitmap.GetPixelFormatSize(source.PixelFormat);

                // Check if bpp (Bits Per Pixel) is 8, 24, or 32
                if (Depth != 8 && Depth != 24 && Depth != 32)
                {
                    throw new ArgumentException("Only 8, 24 and 32 bpp images are supported.");
                }

                // Lock bitmap and return bitmap data
                bitmapData = source.LockBits(rect, ImageLockMode.ReadWrite,
                                             source.PixelFormat);

                //得到首地址
                unsafe
                {
                    Iptr = bitmapData.Scan0;
                    //二維圖像循環

                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        public void UnlockBits()
        {
            try
            {
                source.UnlockBits(bitmapData);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        public Color GetPixel(int x, int y)
        {
            unsafe
            {
                byte* ptr = (byte*)Iptr;
                ptr = ptr + bitmapData.Stride * y;
                ptr += Depth * x / 8;
                Color c = Color.Empty;
                if (Depth == 32)
                {
                    int a = ptr[3];
                    int r = ptr[2];
                    int g = ptr[1];
                    int b = ptr[0];
                    c = Color.FromArgb(a, r, g, b);
                }
                else if (Depth == 24)
                {
                    int r = ptr[2];
                    int g = ptr[1];
                    int b = ptr[0];
                    c = Color.FromArgb(r, g, b);
                }
                else if (Depth == 8)
                {
                    int r = ptr[0];
                    c = Color.FromArgb(r, r, r);
                }
                return c;
            }
        }

        public void SetPixel(int x, int y, Color c)
        {
            unsafe
            {
                byte* ptr = (byte*)Iptr;
                ptr = ptr + bitmapData.Stride * y;
                ptr += Depth * x / 8;
                if (Depth == 32)
                {
                    ptr[3] = c.A;
                    ptr[2] = c.R;
                    ptr[1] = c.G;
                    ptr[0] = c.B;
                }
                else if (Depth == 24)
                {
                    ptr[2] = c.R;
                    ptr[1] = c.G;
                    ptr[0] = c.B;
                }
                else if (Depth == 8)
                {
                    ptr[2] = c.R;
                    ptr[1] = c.G;
                    ptr[0] = c.B;
                }
            }
        }
    }
}