BMP width and height, BinaryReader Learn programming C#



Lesson:

File Management


Exercise:

BMP width and height, BinaryReader


Objetive:

Create a C# program to display the width and height of a BMP file using a BinaryReader.

The structure of the header of a BMP file is:

File type (letters BM) at positions 0-1.
File size at positions 2-5.
Reserved at positions 6-7.
Reserved at positions 8-9.
Start of image data at positions 10-13.
Size of bitmap header at positions 14-17.
Width (pixels) at positions 18-21.
Height (pixels) at positions 22-25.
Number of planes at positions 26-27.
Size of each point at positions 28-29.
Compression (0=not compressed) at positions 30-33.
Image size at positions 34-37.
Horizontal resolution at positions 38-41.
Vertical resolution at positions 42-45.
Size of color table at positions 46-49.


Code:

using System;
using System.IO;
public class BmpHeightWidth
{
    public static void Main()
    {
        BinaryReader myFile;
        byte b1, b2;
        int width, height;

        myFile = new BinaryReader(
            File.Open("example.bmp", FileMode.Open));
        b1 = myFile.ReadByte();
        b2 = myFile.ReadByte();

        if ((b1 == 0x42) && (b2 == 0x4D))
        {
            Console.WriteLine("It seems to be a BMP file");
            myFile.BaseStream.Seek(18, SeekOrigin.Begin);
            width = myFile.ReadInt32();
            height = myFile.ReadInt32();
            Console.WriteLine("Width: {0} pixels", width);
            Console.WriteLine("Height: {0} pixels", height);
        }
        else
            Console.WriteLine("It DOES NOT seem to be a BMP file");

        myFile.Close();
    }
}



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