Write Alpha Jpg : JPG « 2D Graphics « C# / C Sharp

1. C# / C Sharp
2. 2D Graphics
3. JPG

Write Alpha Jpg

       
/* Copyright (C) 2008 Robin Debreuil -- Released under the BSD License */

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;

namespace DDW.Swf
{
  public class Utils
  {
    public const uint TwipsPerPixel = 20;


    public static void WriteAlphaJpg(byte[] alphaData, Bitmap jpg, string pngDest)
    {
      int w = jpg.Width;
      int h = jpg.Height;
      Bitmap png = new Bitmap(w, h, PixelFormat.Format32bppArgb);
      

       BitmapData jpgData = jpg.LockBits(
         new Rectangle(0, 0, w, h),
         ImageLockMode.ReadOnly, 
         PixelFormat.Format24bppRgb);

       BitmapData pngData = png.LockBits(
         new Rectangle(0, 0, w, h),
         ImageLockMode.WriteOnly, 
         PixelFormat.Format32bppArgb);

      unsafe
      {
        byte* jpgStart = (byte*)jpgData.Scan0.ToPointer();
        byte* pngStart = (byte*)pngData.Scan0.ToPointer();
        int jpgStride = jpgData.Stride;
        int pngStride = pngData.Stride;

        for (int y = 0; y < h; y++)
        {
          byte* jpgRow = (byte*)(jpgStart + y * jpgStride);
          byte* pngRow = (byte*)(pngStart + y * pngStride);

          for (int x = 0; x < w; x++) // 3 bpp
          {
            int pngX = x * 4;
            int jpgX = x * 3;
            pngRow[pngX] = jpgRow[jpgX];
            pngRow[pngX + 1] = jpgRow[jpgX + 1];
            pngRow[pngX + 2] = jpgRow[jpgX + 2];
            pngRow[pngX + 3] = alphaData[y*w + x];
          }
        }
      }       
      jpg.UnlockBits(jpgData);
      png.UnlockBits(pngData);

      DDW.Vex.Utils.EnsurePath(pngDest);
      png.Save(pngDest);
      png.Dispose();
    }

    public static Vex.Size GetJpgSize(string path)
    {
      Bitmap bmp = new Bitmap(path, false);
      Vex.Size sz = new DDW.Vex.Size(bmp.Width, bmp.Height);
      bmp.Dispose();
      return sz;
    }

    public static Matrix ScaleBitmapMatrix(Matrix m)
    {
      System.Drawing.Drawing2D.Matrix mx = 
        new System.Drawing.Drawing2D.Matrix(m.ScaleX, m.Rotate0, m.Rotate1, m.ScaleY, m.TranslateX, m.TranslateY);
      mx.Scale(1 / 20F, 1 / 20F);
      float[] els = mx.Elements;
      return new Matrix(els[0], els[1], els[2], els[3], els[4], els[5]);
    }
  }
}

   
    
    
    
    
    
    
  

Related examples in the same category

1.	Load JPG file and paint the image
2.	Convert bmp image format to jpg, gif, png format images