写XIm​​age为.bmp文件用C [英] write XImage to .bmp file in C

问题描述

我写一个XImage到文件bitmap0.bmp使用下面的code，但是当我在Fedora中打开新创建的文件，图像浏览它给错误的文件premature到底，不显示任何内容。任何人都可以请在以下code点出了问题？

I am writing an XImage to a file "bitmap0.bmp" using the following code but when i open the newly created file with imageViewer in fedora it gives "Premature end of file" error and does not display anything. could anyone please point out the problem in the following code?

typedef struct tagBITMAPFILEHEADER {
WORD    bfType;
DWORD   bfSize;
WORD    bfReserved1;
WORD    bfReserved2;
DWORD   bfOffBits;

} BITMAPFILEHEADER;

} BITMAPFILEHEADER;

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

} BITMAPINFOHEADER;

} BITMAPINFOHEADER;

void saveXImageToBitmap(XImage *pImage)
{
BITMAPFILEHEADER bmpFileHeader;
BITMAPINFOHEADER bmpInfoHeader;
FILE *fp;
static int cnt = 0;
int dummy;
char filePath[255];
memset(&bmpFileHeader, 0, sizeof(BITMAPFILEHEADER));
memset(&bmpInfoHeader, 0, sizeof(BITMAPINFOHEADER));
bmpFileHeader.bfType = 0x4D42;
bmpFileHeader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +  pImage->width*pImage->height*4;
bmpFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
bmpFileHeader.bfReserved1 = 0;
bmpFileHeader.bfReserved2 = 0;

bmpInfoHeader.biSize = sizeof(BITMAPINFOHEADER);
bmpInfoHeader.biWidth = pImage->width;
bmpInfoHeader.biHeight = pImage->height;
bmpInfoHeader.biPlanes = 1;
bmpInfoHeader.biBitCount = 32;
dummy = (pImage->width * 3) % 4;
if((4-dummy)==4)
    dummy=0;
else
    dummy=4-dummy;
bmpInfoHeader.biSizeImage = ((pImage->width*3)+dummy)*pImage->height;
bmpInfoHeader.biCompression = 0;
bmpInfoHeader.biXPelsPerMeter = 0;
bmpInfoHeader.biYPelsPerMeter = 0;
bmpInfoHeader.biClrUsed = 0;
bmpInfoHeader.biClrImportant = 0;

sprintf(filePath, "bitmap%d.bmp", cnt++);
fp = fopen(filePath,"wb");

if(fp == NULL)
    return;

fwrite(&bmpFileHeader, sizeof(bmpFileHeader), 1, fp);
fwrite(&bmpInfoHeader, sizeof(bmpInfoHeader), 1, fp);
fwrite(pImage->data, 4*pImage->width*pImage->height, 1, fp);
fclose(fp);

}

推荐答案

感谢您user786653。我检查了我的结构。他们得到填充。我加了

Thank you user786653. I checked my structures. they were getting padded. I added

#pragma pack (1)

在结构，现在它工作正常。 ：）

in structures and now it works fine. :)

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