Mail Archives: djgpp/2003/01/09/06:30:10
On Wed, 8 Jan 2003 04:51:46 +0000 (UTC), "Joel Saunders"
<jbs30000 AT aol DOT com> wrote:
>In writting a simple bmp loader, I'm having problems with the struct for
>the bmp header. Even with __attribute__((__packed__)) after each item:
>struct BMP_Header {
> unsigned int BM __attribute__((__packed__));
> unsigned long File_Size __attribute__((__packed__));
> unsigned int R_1 __attribute__((__packed__)); // Reserved 1
> unsigned int R_2 __attribute__((__packed__)); // Reserved 2
> unsigned long BMP_Offset __attribute__((__packed__));
> unsigned long Header_Info __attribute__((__packed__));
> unsigned long BMP_Width __attribute__((__packed__));
> unsigned long BMP_Height __attribute__((__packed__));
> unsigned int BMP_Planes __attribute__((__packed__));
> unsigned int BPP __attribute__((__packed__)); // Bytes Per Scan
>Line
> unsigned long Compression __attribute__((__packed__));
> unsigned long BMP_Size __attribute__((__packed__));
> unsigned long Width_PPM __attribute__((__packed__));
> unsigned long Height_PPM __attribute__((__packed__));
> unsigned long Num_of_Colors __attribute__((__packed__));
> unsigned long Important_Colors __attribute__((__packed__));
>}image;
>I had to do this to use the header information:
>unsigned char image[54];
>#define image_BM ((int *)&image[0])[0]
>#define image_File_Size ((long *)&image[2])[0]
>#define image_R_1 ((int *)&image[6])[0]
>#define image_R_2 ((int *)&image[8])[0]
>#define image_BMP_Offset ((long *)&image[10])[0]
>#define image_Header_Info ((long *)&image[14])[0]
>#define image_BMP_Width ((long *)&image[18])[0]
>#define image_BMP_Height ((long *)&image[22])[0]
>#define image_BMP_Planes ((int *)&image[26])[0]
>#define image_BPP ((int *)&image[28])[0]
>#define image_Compression ((long *)&image[30])[0]
>#define image_BMP_Size ((long *)&image[34])[0]
>#define image_Width_PPM ((long *)&image[38])[0]
>#define image_Height_PPM ((long *)&image[42])[0]
>#define image_Num_of_Colors ((long *)&image[46])[0]
>#define image_Important_Colors ((long *)&image[50])[0]
>To load the bmp header, I'm using fread (if that makes any difference).
>And the program is using C, not CPP files (if that also, makes any
>difference.)
use short instead of int for now, until you can use int16_t (C99)
Thanks. Take care, Brian Inglis Calgary, Alberta, Canada
--
Brian DOT Inglis AT CSi DOT com (Brian dot Inglis at SystematicSw dot ab dot ca)
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