copymemory.txt

将BMP

将BMP，24位图读入内存中。看代码后就能理解了。
unsigned char *LoadBitmapFile(char *filename, BITMAPINFOHEADER *bitmapInfoHeader)
{
	FILE *filePtr;							
	BITMAPFILEHEADER	bitmapFileHeader;		
	unsigned char		*bitmapImage;			
	int					imageIdx = 0;		
	unsigned char		tempRGB;			
	filePtr = fopen(filename, "rb");
	if (filePtr == NULL)
		return NULL;
	fread(&bitmapFileHeader, sizeof(BITMAPFILEHEADER), 1, filePtr);
	if (bitmapFileHeader.bfType != BITMAP_ID)
	{
		fclose(filePtr);
		return NULL;
	}
	fread(bitmapInfoHeader, sizeof(BITMAPINFOHEADER), 1, filePtr);
	fseek(filePtr, bitmapFileHeader.bfOffBits, SEEK_SET);
	bitmapImage = (unsigned char*)malloc(bitmapInfoHeader->biSizeImage);
if (!bitmapImage)
	{
		free(bitmapImage);
		fclose(filePtr);
		return NULL;
	}
	fread(bitmapImage, 1, bitmapInfoHeader->biSizeImage, filePtr);
	if (bitmapImage == NULL)
	{
		fclose(filePtr);
		return NULL;
	}
    //r-b交换
	for (imageIdx = 0; imageIdx < bitmapInfoHeader->biSizeImage; imageIdx+=3)
	{
		tempRGB = bitmapImage[imageIdx];
		bitmapImage[imageIdx] = bitmapImage[imageIdx + 2];
		bitmapImage[imageIdx + 2] = tempRGB;
	}
	fclose(filePtr);
	return bitmapImage;
}