無法在 C 中讀取 (1280 x 960) .bmp 圖像的位圖數據

Question

我正在嘗試打開 .bmp 圖像文件並將位圖數據讀取到緩沖區。 但我沒有得到例外的輸出。 我是 C 語言的新手，請在這種情況下幫助我。

這是我的“main.c”文件。

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

typedef uint32_t DWORD;   // DWORD = unsigned 32 bit value
typedef uint16_t WORD;    // WORD = unsigned 16 bit value

#pragma pack(push, 1)

typedef struct {
    WORD bfType;  //specifies the file type
    DWORD bfSize;  //specifies the size in bytes of the bitmap file
    WORD bfReserved1;  //reserved; must be 0
    WORD bfReserved2;  //reserved; must be 0
    DWORD offset;  //specifies the offset in bytes from the bitmapfileheader to the bitmap bits
} BMP_FILE_HEADER;

#pragma pack(pop)

 unsigned char *LoadBitmapFile(char *filename)
{
    FILE *filePtr;  //our file pointer
    BMP_FILE_HEADER bitmapFileHeader;  //our bitmap file header
    unsigned char *bitmapImage;  //store image data
    size_t bytes_read;

    //open file in read binary mode
    filePtr = fopen(filename,"rb");
    if (filePtr == NULL)
        return NULL;

    //read the bitmap file header
    fread(&bitmapFileHeader,1,sizeof(BMP_FILE_HEADER),filePtr);
    printf("Type : %d \n",bitmapFileHeader.bfType );

    //verify that this is a .BMP file by checking bitmap id
    if (bitmapFileHeader.bfType !=0x4D42)
    {
        printf("This is not a bitmap" );

        fclose(filePtr);
        return NULL;
    }

    //move file pointer to the beginning of bitmap data
    fseek(filePtr,bitmapFileHeader.offset, SEEK_SET);
    printf("Where is the file pointer = %ld \n", ftell(filePtr) );

    //allocate enough memory for the bitmap image data
    bitmapImage = (unsigned char*)malloc(1280*960);

    //verify memory allocation
    if (!bitmapImage)
    {   
      printf("Memory Allocation failed" );
        free(bitmapImage);
        fclose(filePtr);
        return NULL;
    }


    //read in the bitmap image data
    bytes_read = fread(bitmapImage,1,1280*960 ,filePtr);
    printf("Read Bytes : %zu\n",bytes_read );

    //make sure bitmap image data was read
    if (bitmapImage == NULL)
    {
      printf("data was not read" );
        fclose(filePtr);
        return NULL;
    }
    printf("bitmapImage: %s\n", bitmapImage );

    printf("Header- size -> %i\n",bitmapFileHeader.bfSize );
    printf("Header- OffSet -> %i\n",bitmapFileHeader.offset );

    //close file and return bitmap image data
    fclose(filePtr);
    return bitmapImage;
}

int  main(){
  
  unsigned char *bitmapData;
  bitmapData = LoadBitmapFile("img_06.bmp");
  
  printf("bitmapData: %s", bitmapData );

return 0;
}

這是輸出：

我無法打印“bitmapData”緩沖區的任何數據。 這是我在程序中使用的 .bmp 文件。

圖像大小（1,229,878 字節）
寬1280像素/高960像素

Answer 1

I replaced the line,
printf("bitmapData: %s", bitmapData );

with 
printf("bitmapData: "); fwrite(bitmapData, 1280*960, 1, stdout);