image viewer for reading bitmap file by binary reading

Question

after reading the algorithm of bitmap files i have created a small program which is not working properly but displaying zigzag pattern

my code is this

public void display(String filename)
        {
            FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
            BinaryReader br = new BinaryReader(fs);
            if (br.ReadChar().ToString() + br.ReadChar().ToString() == "BM")
            {
                bfSize = br.ReadInt32();
                bfReserved1 = br.ReadInt16();
                bfReserved2 = br.ReadInt16();
                bfoffbits = br.ReadInt32();
                biSize = br.ReadInt32();
                biWidth = br.ReadInt32();
                biHeight = br.ReadInt32();
                biPlanes = br.ReadInt16();
                biBitCount = br.ReadInt16();
                biCompression = br.ReadInt32();
                biSizeImage = br.ReadInt32();
                biXPelsPerMeter = br.ReadInt32();
                biYPelsPerMeter = br.ReadInt32();
                biClrUsed = br.ReadInt32();
                biClrImportant = br.ReadInt32();
                Bitmap bmp = new Bitmap((int)biWidth,(int)biHeight);
                pictureBox1.Size = new Size((int)biWidth, (int)biHeight);
                try
                {
                    for (int x = 0; x < biWidth ; x++)
                    {
                        for (int y = (int)biHeight-1; y >= 0; y--)
                        {
                            rgbRed=br.ReadByte();
                            rgbGreen=br.ReadByte();
                            rgbBlue = br.ReadByte();
                            bmp.SetPixel(x,y,Color.FromArgb(rgbRed,rgbGreen,rgbBlue));
                        }
                    }
                    pictureBox1.Image = bmp;
                }
                catch
                {
                    MessageBox.Show("there is some problem with file format");
                }
            }
            else
                MessageBox.Show("this is not a bitmap file");
            fs.Flush();
        }

please help

garry craig · Answer

hey I found a couple of problems with your code. You were reading the bytes in the wrong order its not Red Green Blue but Blue Green Red. The reading of the image was also reading column by column instead of row by row. Fixed Code public void display(String filename) { FileStream fs = new FileStream(filename FileMode.Open FileAccess.Read); BinaryReader br = new BinaryReader(fs); if (br.ReadChar().ToString() + br.ReadChar().ToString() == BM) { int bfSize = br.ReadInt32(); int bfReserved1 = br.ReadInt16(); int bfReserved2 = br.ReadInt16(); int bfoffbits = br.ReadInt32(); int biSize = br.ReadInt32(); int biWidth = br.ReadInt32(); int biHeight = br.ReadInt32(); int biPlanes = br.ReadInt16(); int biBitCount = br.ReadInt16(); int biCompression = br.ReadInt32(); int biSizeImage = br.ReadInt32(); int biXPelsPerMeter = br.ReadInt32(); int biYPelsPerMeter = br.ReadInt32(); int biClrUsed = br.ReadInt32(); int biClrImportant = br.ReadInt32(); int rgbRed = 0; int rgbGreen = 0; int rgbBlue = 0; Bitmap bmp = new Bitmap(biWidth biHeight); pictureBox1.Size = new Size(biWidth biHeight); try { for (int y = biHeight- 1; y >= 0; y--) { for (int x = 0; x { rgbBlue = br.ReadByte(); rgbGreen = br.ReadByte(); rgbRed = br.ReadByte(); bmp.SetPixel(x y Color.FromArgb(rgbRed rgbGreen rgbBlue)); } } pictureBox1.Image = bmp; } catch { MessageBox.Show(there is some problem with file format); } } else MessageBox.Show(this is not a bitmap file); fs.Flush(); }

tarun kumar · Answer

thanx for reply now my programs runs well but i have one more doubt and that is about the image i have seen by not doing what you have told me know. that image look blackish what is the reason behind this?

moud man · Answer

Hi all the code also missing the padding after each row of the image u must read the extra padding bytes in the row coz the row must be multiple of 4 so add this line before the loops ---- int padding = biWidth % 4; ---- then add this line after the inner loop ---- fs.Seek( padding SeekOrigin.Current); ----

tarun kumar · Answer

view in my viewer actual view

garry craig · Answer

I dont know what that could be. Could you make a screen shot of the image that is displayed tilted? Garry

tarun kumar · Answer

thanx man there is one more problem in that program the image is displayed tilt.