BMP文件结构.zip (13.26 KB)

程序代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

typedef unsigned char  BYTE;
typedef unsigned short WORD;
typedef unsigned long  DWORD;
typedef long                 LONG;

#pragma pack(2)

typedef struct {
        WORD    bfType;
        DWORD   bfSize;
        WORD    bfReserved1;
        WORD    bfReserved2;
        DWORD   bfOffBits;
} BITMAPFILEHEADER;

typedef struct {
        DWORD      biSize;
        LONG       biWidth;
        LONG       biHeight;
        WORD       biPlanes;
        WORD       biBitCount;
        DWORD      biCompression;
        DWORD      biSizeImage;
        LONG       biXPelsPerMeter;
        LONG       biYPelsPerMeter;
        DWORD      biClrUsed;
        DWORD      biClrImportant;
} BITMAPINFOHEADER;

void saveBitmap()
{
   // Define BMP Size
   const int height = 600;
   const int width = 800;
   const int size = height * width * 3;
   double x, y;
   int index;

   // Part.1 Create Bitmap File Header
   BITMAPFILEHEADER fileHeader;

   fileHeader.bfType = 0x4D42;
   fileHeader.bfReserved1 = 0;
   fileHeader.bfReserved2 = 0;
   fileHeader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + size;
   fileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);

   // Part.2 Create Bitmap Info Header
   BITMAPINFOHEADER bitmapHeader = {0};

   bitmapHeader.biSize = sizeof(BITMAPINFOHEADER);
   bitmapHeader.biHeight = height;
   bitmapHeader.biWidth = width;
   bitmapHeader.biPlanes = 3;
   bitmapHeader.biBitCount = 24;
   bitmapHeader.biSizeImage = size;
   bitmapHeader.biCompression = 0; //BI_RGB

   // Part.3 Create Data
   BYTE *bits = (BYTE *)malloc(size);

   // Clear
   memset(bits, 0xFF, size);

   // Sin Graph
   for(x = 0; x < 800; x += 0.5)
   {
      y = sin(x / 100.0) * 200 + 300;
      index = (int)y * 800 * 3 + (int)x * 3;

      bits[index + 0] = 255; // Blue
      bits[index + 1] = 0;   // Green
      bits[index + 2] = 0;   // Red
   }

   // Write to file
   FILE *output = fopen("output.bmp", "wb");

   if(output == NULL)
   {
      printf("Cannot open file!\n");
   }
   else
   {
      fwrite(&fileHeader, sizeof(BITMAPFILEHEADER), 1, output);
      fwrite(&bitmapHeader, sizeof(BITMAPINFOHEADER), 1, output);
      fwrite(bits, size, 1, output);
      fclose(output);
   }
}

int main()
{
   saveBitmap();

   return 0;
}