MS-BmpMakerClass-cs

using System;
using System.IO;
using System.Linq;
using Xamarin.Forms;
using System.Text;

using System.Collections.Generic;

namespace MandelBrootSet
{
    public class BmpMaker
    {
        const int headerSize = 54;
        readonly byte[] buffer;
        public BmpMaker(int width, int height)
        {
            Width = width;
            Height = height;
            int numPixels = Width * Height;
            int numPixelBytes = 4 * numPixels;
            int fileSize = headerSize + numPixelBytes;
            buffer = new byte[fileSize];
            // Escritor y acumulador de encabezados: Buffer.
            using (MemoryStream memoryStream = new MemoryStream(buffer))
            {
                //Asignación binaria del archivo temporal.
                using (BinaryWriter writer = new BinaryWriter(memoryStream, Encoding.UTF8))
                {
                    // Constructor del encabezado del BitMap (14 bytes).
                     writer.Write(new char[] { 'B', 'M' });
                     writer.Write(fileSize);
                     writer.Write((short)0);
                     writer.Write((short)0);
                     writer.Write(headerSize);
                     // Constructor BitmapInfoHeader (40 bytes).
                     writer.Write(40); // Header size
                     writer.Write(Width);
                     writer.Write(Height);
                     writer.Write((short)1); //Tasa
                     writer.Write((short)32); //Tasa
                     writer.Write(0); // Compresión
                     writer.Write(numPixelBytes); //Balanza de imagen en pixeles.
                     writer.Write(0); //Densidad de Pixels/Color
                     writer.Write(0);
                     writer.Write(0);
                     writer.Write(0);
                }
            }
        }
        //Instanciando Ancho y Altura
        public int Width
        {
            private set;
            get;
        }
        public int Height
        {
            private set;
            get;
        }
        //Funciones de configuración de Color y carga del Buffer
        public void SetPixel(int row, int col, Color color)
        {
            SetPixel(row, col,  (int)(255 * color.R),
                                (int)(255 * color.G),
                                (int)(255 * color.B),
                                (int)(255 * color.A));
        }
        public void SetPixel(int row, int col, int r, int g, int b, int a = 255)
        {
            int index = (row * Width + col) * 4 + headerSize;
            buffer[index + 0] = (byte)b;
            buffer[index + 1] = (byte)g;
            buffer[index + 2] = (byte)r;
            buffer[index + 3] = (byte)a;
        }
        //Método para generar la imagen.
        public ImageSource Generate()
        {
            // Creando el MemoryStream a partir del Buffer colector de bitmaps.
            MemoryStream memoryStream = new MemoryStream(buffer);
            // Conversión a StreamImageSource.
            ImageSource imageSource = ImageSource.FromStream(() =>
            {
                return memoryStream;
            });
            return imageSource;
        }
    }
}