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

namespace ClassLibrary
{
    public class ImageProcessing
    {

        public bool calculateWhitePixels (string strFileName, ref int nBlackCount, ref int nWhiteCount, ref int nTotalPixels)
        {
            Image image = null;
            Bitmap bmpCrop = null;

            BitmapData bmpData = null;
            byte[] imgData = null;
            int n = 0;

            try
            {
                image = new Bitmap(strFileName);
                bmpCrop = new Bitmap(image);

                //nBlackPercent = 0;
                //nWhitePercent = 0;

                for (int h = 0; h < bmpCrop.Height; h++)// scan through all rows of image
                {
                    // This part is a very fast replacement of getPixel() method
                    bmpData = bmpCrop.LockBits(new Rectangle(0, h, bmpCrop.Width, 1),
                    ImageLockMode.ReadOnly, image.PixelFormat);
                    imgData = new byte[bmpData.Stride];
                    Marshal.Copy(bmpData.Scan0, imgData, 0, imgData.Length);
                    bmpCrop.UnlockBits(bmpData);

                    for (n = 0; n < imgData.Length - 3; n += 3)// scanning width of image
                    {
                        if ((int)imgData[n] == 0 && (int)imgData[n + 1] == 0 && (int)imgData[n + 2] == 0)// Color black is #000000
                        {
                            nBlackCount++;
                        }
                        else
                        {
                            nWhiteCount++;
                        }
                    }

                    nTotalPixels += n;
                }

                string.Format("{0} pixels are black, {1} are white(or non black at least).", nBlackCount, nWhiteCount);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

            return nWhiteCount > 0;
        }

        public static unsafe bool DetectColorAllBlack(Bitmap bmp)
        {
            // Lock the bitmap's bits.  
            Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
            BitmapData bmpData = bmp.LockBits(rect, ImageLockMode.ReadWrite, bmp.PixelFormat);

            // Get the address of the first line.
            IntPtr ptr = bmpData.Scan0;

            // Declare an array to hold the bytes of the bitmap.
            int bytes = bmpData.Stride * bmp.Height;
            byte[] rgbValues = new byte[bytes];

            // Copy the RGB values into the array.
            Marshal.Copy(ptr, rgbValues, 0, bytes);

            // Scanning for non-zero bytes
            for (int index = 0; index < rgbValues.Length; index++)
                if (rgbValues[index] != 0 && (index + 1) % 4 != 0)
                    return false;
            // Unlock the bits.
            bmp.UnlockBits(bmpData);

            return true;
        }

        public static Bitmap CreateThumbnail(string lcFilename, int lnWidth, int lnHeight)
        {
            System.Drawing.Bitmap bmpOut = null;
            try
            {
                Bitmap loBMP = new Bitmap(lcFilename);
                ImageFormat loFormat = loBMP.RawFormat;

                decimal lnRatio;
                int lnNewWidth = 0;
                int lnNewHeight = 0;

                //*** If the image is smaller than a thumbnail just return it
                if (loBMP.Width < lnWidth && loBMP.Height < lnHeight)
                    return loBMP;

                if (loBMP.Width > loBMP.Height)
                {
                    lnRatio = (decimal)lnWidth / loBMP.Width;
                    lnNewWidth = lnWidth;
                    decimal lnTemp = loBMP.Height * lnRatio;
                    lnNewHeight = (int)lnTemp;
                }
                else
                {
                    lnRatio = (decimal)lnHeight / loBMP.Height;
                    lnNewHeight = lnHeight;
                    decimal lnTemp = loBMP.Width * lnRatio;
                    lnNewWidth = (int)lnTemp;
                }
                bmpOut = new Bitmap(lnNewWidth, lnNewHeight);
                Graphics g = Graphics.FromImage(bmpOut);
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight);
                g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight);

                loBMP.Dispose();
            }
            catch
            {
                return null;
            }

            return bmpOut;
        }

        public static Bitmap CreateThumbnail(Bitmap loBMP, int lnWidth, int lnHeight)
        {
            System.Drawing.Bitmap bmpOut = null;
            try
            {
                ImageFormat loFormat = loBMP.RawFormat;

                decimal lnRatio;
                int lnNewWidth = 0;
                int lnNewHeight = 0;

                //*** If the image is smaller than a thumbnail just return it
                if (loBMP.Width < lnWidth && loBMP.Height < lnHeight)
                    return loBMP;

                if (loBMP.Width > loBMP.Height)
                {
                    lnRatio = (decimal)lnWidth / loBMP.Width;
                    lnNewWidth = lnWidth;
                    decimal lnTemp = loBMP.Height * lnRatio;
                    lnNewHeight = (int)lnTemp;
                }
                else
                {
                    lnRatio = (decimal)lnHeight / loBMP.Height;
                    lnNewHeight = lnHeight;
                    decimal lnTemp = loBMP.Width * lnRatio;
                    lnNewWidth = (int)lnTemp;
                }
                bmpOut = new Bitmap(lnNewWidth, lnNewHeight);
                Graphics g = Graphics.FromImage(bmpOut);
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight);
                g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight);

                loBMP.Dispose();
            }
            catch
            {
                return null;
            }

            return bmpOut;
        }


    }
}