using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace HNWD.Pregrant.Common
{
    public class BitmapBlack
    {
        public static bool bSuccessed = true;

        public static Bitmap BitmapToBlack(Bitmap img, Double hsb)
        {
            int w = img.Width;
            int h = img.Height;
            Bitmap bmp = new Bitmap(w, h, PixelFormat.Format1bppIndexed);
            BitmapData data = bmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadWrite, PixelFormat.Format1bppIndexed);//将 Bitmap 锁定到系统内存中
            for (int y = 0; y < h; y++)
            {
                byte[] scan = new byte[(w + 7) / 8];
                for (int x = 0; x < w; x++)
                {
                    Color c = img.GetPixel(x, y);

                    if (c.GetBrightness() >= hsb)
                        scan[x / 8] |= (byte)(0x80 >> (x % 8));//亮度值和原来比较，二值化处理
                }
                Marshal.Copy(scan, 0, (IntPtr)((int)data.Scan0 + data.Stride * y), scan.Length);
            }
            bmp.UnlockBits(data);//将 Bitmap 锁定到系统内存中

            return bmp;
        }

        //图片二值化
        public static Bitmap binarization(Bitmap img)
        {
            bSuccessed = true;

            int width = img.Width;
            int height = img.Height;
            int area = width * height;
            int[,] gray = new int[width, height];
            int average = 0;// 灰度平均值
            int graysum = 0;
            int graymean = 0;
            int grayfrontmean = 0;
            int graybackmean = 0;
            int pixelGray;
            int front = 0;
            int back = 0;
            int[] pix = new int[width * height];

            for (int i = 1; i < width; i++)
            { // 不算边界行和列，为避免越界
                for (int j = 1; j < height; j++)
                {
                    pix[j * width + i] = img.GetPixel(i, j).ToArgb(); //得到单点上的颜色值
                    int x = j * width + i;
                    int r = (pix[x] >> 16) & 0xff;
                    int g = (pix[x] >> 8) & 0xff;
                    int b = pix[x] & 0xff;
                    pixelGray = (int)(0.3 * r + 0.59 * g + 0.11 * b);// 计算每个坐标点的灰度
                    gray[i, j] = (pixelGray << 16) + (pixelGray << 8) + (pixelGray);
                    graysum += pixelGray;
                }
            }
            graymean = (int)(graysum / area);// 整个图的灰度平均值
            average = graymean;
            for (int i = 0; i < width; i++) // 计算整个图的二值化阈值
            {
                for (int j = 0; j < height; j++)
                {
                    if (((gray[i, j]) & (0x0000ff)) < graymean)
                    {
                        graybackmean += ((gray[i, j]) & (0x0000ff));
                        back++;
                    }
                    else
                    {
                        grayfrontmean += ((gray[i, j]) & (0x0000ff));
                        front++;
                    }
                }
            }

            if (front == 0 || back == 0)
            {
                bSuccessed = false;
                return null;
            }

            int frontvalue = (int)(grayfrontmean / front);// 前景中心
            int backvalue = (int)(graybackmean / back);// 背景中心
            float[] G = new float[frontvalue - backvalue + 1];// 方差数组
            int s = 0;

            for (int i1 = backvalue; i1 < frontvalue + 1; i1++)// 以前景中心和背景中心为区间采用大津法算法（OTSU算法）
            {
                back = 0;
                front = 0;
                grayfrontmean = 0;
                graybackmean = 0;
                for (int i = 0; i < width; i++)
                {
                    for (int j = 0; j < height; j++)
                    {
                        if (((gray[i, j]) & (0x0000ff)) < (i1 + 1))
                        {
                            graybackmean += ((gray[i, j]) & (0x0000ff));
                            back++;
                        }
                        else
                        {
                            grayfrontmean += ((gray[i, j]) & (0x0000ff));
                            front++;
                        }
                    }
                }

                if (front == 0 || back == 0)
                {
                    bSuccessed = false;
                    return null;
                }

                grayfrontmean = (int)(grayfrontmean / front);
                graybackmean = (int)(graybackmean / back);

                G[s] = (((float)back / area) * (graybackmean - average)
                      * (graybackmean - average) + ((float)front / area)
                      * (grayfrontmean - average) * (grayfrontmean - average));
                s++;
            }
            float max = G[0];
            int index = 0;
            for (int i = 1; i < frontvalue - backvalue + 1; i++)
            {
                if (max < G[i])
                {
                    max = G[i];
                    index = i;
                }
            }

            for (int i = 0; i < width; i++)
            {
                for (int j = 0; j < height; j++)
                {
                    int inin = j * width + i;
                    if (((gray[i, j]) & (0x0000ff)) < (index + backvalue))
                    {
                        pix[inin] = Color.FromArgb(0, 0, 0).ToArgb();
                    }
                    else
                    {
                        pix[inin] = Color.FromArgb(255, 255, 255).ToArgb();
                    }
                }
            }

            Bitmap temp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format16bppRgb555);

            for (int i = 1; i < width; i++)
            { // 不算边界行和列，为避免越界
                for (int j = 1; j < height; j++)
                {
                    img.SetPixel(i, j, Color.FromArgb(pix[j * width + i]));
                }
            }

            return temp;
        }

        /// <summary>
        /// 防锯齿
        /// </summary>
        /// <param name="uAction"></param>
        /// <param name="uParam"></param>
        /// <param name="lpvParam"></param>
        /// <param name="fuWinIni"></param>
        /// <returns></returns>

        [DllImport("user32.dll", EntryPoint = "SystemParametersInfo")]
        private static extern int SystemParametersInfo(int uAction,
                                                        int uParam,
                                                        string lpvParam,
                                                        int fuWinIni
                                                        );

        private static int BitmapHandlerAction = 75;//启用 或 关闭 平滑效果

        /// <summary>
        /// 关闭 平滑效果
        /// </summary>
        /// <returns></returns>
        public static int SetBitmapSmoothDisable()
        {
            return SystemParametersInfo(BitmapHandlerAction, 0, null, 0); //关闭 平滑效果
        }

        /// <summary>
        /// 启用 平滑效果
        /// </summary>
        /// <returns></returns>
        public static int SetBitmapSmoothEnable()
        {
            return SystemParametersInfo(BitmapHandlerAction, 1, null, 0); //关闭 平滑效果
        }
    }
}