//// This code is part of Document Solutions for Imaging demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using System.Drawing;using GrapeCity.Documents.Drawing;using GrapeCity.Documents.Imaging;
namespace DsImagingWeb.Demos{    // This sample demonstrates how to swap color channels on an image    // using pixel access. Here we swap red and blue channels to    // change the way the image looks.    public class SwapColors    {        public GcBitmap GenerateImage(Size pixelSize, float dpi, bool opaque, string[] sampleParams = null)        {            var bmp = new GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi);            using (var bmpSrc = new GcBitmap(Path.Combine("Resources", "ImagesBis", "alpamayo-sq.jpg")))            {                // BitBlt requires the opacity of both images to be the same:                bmpSrc.Opaque = opaque;                // Render source image onto the target bitmap                // (generally we might want to resize the source image first,                // but in this case we just know that the source image has                // the same size as the target, so skip this step):                bmp.BitBlt(bmpSrc, 0, 0);
                using (var g = bmp.CreateGraphics())                {                    for (int i = 0; i < bmp.PixelWidth; ++i)                        for (int j = 0; j < bmp.PixelHeight; ++j)                        {#if bad_performance // Due to the number of pixels, it is better to optimize pixel operations                            var color = Color.FromArgb((int)bmp[i, j]);                            var t = color.B;                            color = Color.FromArgb(color.A, color.B, color.G, color.R);                            bmp[i, j] = (uint)color.ToArgb();#else                            uint px = bmp[i, j];                            px = ((px & 0x000000FF) << 16) | ((px & 0x00FF0000) >> 16) | (px & 0xFF00FF00);                            bmp[i, j] = px;#endif                        }                    // Draw the original image in the bottom right corner for reference:                    float sx = pixelSize.Width / 3, sy = pixelSize.Height / 3;                    g.DrawImage(bmpSrc, new RectangleF(sx * 2, sy * 2, sx, sy), null, ImageAlign.StretchImage);                }            }            return bmp;        }    }}