bmp.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/malloc.h>
typedef unsigned long DWORD;
typedef int BOOL;
typedef unsigned char BYTE;
typedef unsigned short WORD;
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;
int ReadBmp(const char *szFileName);
int GetDIBColor(int X, int Y, BYTE *r, BYTE *g, BYTE *b);
BITMAPINFOHEADER bih;
BYTE *Buffer = NULL;
long LineByteWidth;
int main(void)
{
	int x, y;
	BYTE r, g, b;
	int n;
	char szfilename[255] = "diablo3_pose_diffuse.bmp";
	if (ReadBmp(szfilename) == 0)
	{
		printf("failure to read file %s", szfilename);
		return 1;
	}
	printf("Width: %ld\n", bih.biWidth);
	printf("Height: %ld\n", bih.biHeight);
	printf("BitCount: %d\n\n", (int)bih.biBitCount);
	while (1)
	{
		printf("input the X:");
		scanf("%d", &x);
		if (x < 0)
			break;
		printf("input the Y:");
		scanf("%d", &y);
		if (GetDIBColor(x, y, &r, &g, &b) == 1)
			printf("(%d, %d): r:%d, g:%d, b:%d\n", x, y, (int)r, (int)g, (int)b);
		else
			printf("input error.\n");
	}
	free(Buffer);
	return 0;
}
int ReadBmp(const char *szFileName)
{
	FILE *file;
	WORD bfh[7];
	long dpixeladd;
	if (NULL == (file = fopen(szFileName, "rb")))
	{
		return 0;
	}
	printf("%s\n", szFileName);
	fread(&bfh, sizeof(WORD), 7, file);
	if (bfh[0] != (WORD)(((WORD)'B') | ('M' << 8)))
	{
		fclose(file);
		return 0;
	}
	fread(&bih, sizeof(BITMAPINFOHEADER), 1, file);
	if (bih.biBitCount < 24)
	{
		fclose(file);
		return 0;
	}
	dpixeladd = bih.biBitCount / 8;
	LineByteWidth = bih.biWidth * (dpixeladd);
	if ((LineByteWidth % 4) != 0)
		LineByteWidth += 4 - (LineByteWidth % 4);
	if ((Buffer = (BYTE *)malloc(sizeof(BYTE) * LineByteWidth * bih.biHeight)) != NULL)
	{
		fread(Buffer, LineByteWidth * bih.biHeight, 1, file);
		fclose(file);
		return 1;
	}
	fclose(file);
	return 0;
}
int GetDIBColor(int X, int Y, BYTE *r, BYTE *g, BYTE *b)
{
	int dpixeladd;
	BYTE *ptr;
	if (X < 0 || X >= bih.biWidth || Y < 0 || Y >= bih.biHeight)
	{
		return 0;
	}
	dpixeladd = bih.biBitCount / 8;
	ptr = Buffer + X * dpixeladd + (bih.biHeight - 1 - Y) * LineByteWidth;
	*b = *ptr;
	*g = *(ptr + 1);
	*r = *(ptr + 2);
	return 1;
}