fb_ops_user

/* 打开帧缓冲设备 */
int openFB(const char *name)
{
	int fh;
	char *dev;

	if(name == NULL)
	{
		dev = getenv("FRAMEBUFFER");
		if(dev)
			name = dev;
		else
			name = DEFAULT_FRAMEBUFFER;
	}

	if((fh = open(name, O_WRONLY)) == -1)
	{
		fprintf(stderr, "open %s: %s\n", name, strerror(errno));
		exit(1);
	}

	return fh;
}

/* 关闭帧缓冲设备 */
int closeFB(int fh)
{
	return close(fh);
}

/* 得到屏幕可变参数 */
void getVarScreenInfo(int fh, struct fb_var_screeninfo *var)
{
	if(ioctl(fh, FBIOGET_VSCREENINFO, var))
	{
		fprintf(stderr, "ioctl FBIOGET_VSCREENINFO: %s\n", strerror(errno));
		exit(1);
	}
}

/* 设置屏幕可变参数 */
void setVarScreenInfo(int fh, struct fb_var_screeninfo *var)
{
	if(ioctl(fh, FBIOPUT_VSCREENINFO, var))
	{
		fprintf(stderr, "ioctl FBIOPUT_VSCREENINFO", strerror(errno));
		exit(1);
	}
}

/* 得到屏幕固定参数 */
void getFixScreenInfo(int fh, struct fb_fix_screeninfo *fix)
{
	if(ioctl(fh, FBIOGET_FSCREENINFO, fix))
	{
		fprintf(stderr, "ioctl FBIOGET_FSCREENINFO", strerror(errno));
		exit(1);
	}
}

/* 构造颜色表 */
void make332map(struct fb_cmap *map)
{
	int rs, gs, bs, i;
	int r = 8, g = 8, b = 4;

	map->red = red;
	map->green = green;
	map->blue = blue;

	rs = 256 / (r - 1);
	gs = 256 / (g - 1);
	bs = 256 / (b - 1);
	
	for(i = 0; i < 256; i++)
	{
		map->red[i] = (rs * ((i / (g * b)) % r)) * 255;
		map->green[i] = (gs * ((i / b) % g)) * 255;
		map->blue[i] = (bs * ((i) % b)) * 255;
	}
}

/* 设置颜色表 */
void set8map(int fh, struct fb_cmap *map)
{
	if(ioctl(fh, FBIOPUTCMAP, map) < 0)
	{
		fprintf(stderr, "Error putting colormap");
		exit(1);
	}
}

/* 构造并设置颜色表 */
void set332map(int fh)
{
	make332map(&map332);
	set8map(fh, &map332);
}

/* 获得颜色表 */
void get8map(int fh, struct fb_cmap *map)
{
	if(ioctl(fh, FBIOGETCMAP, map) < 0)
	{
		fprintf(stderr, "Error getting colormap");
		exit(1);
	}
}

/* 组成BPP = 16时的缓冲数据 */
inline unsigned short make16color(unsigned char r, unsigned char q, unsigned char b)
{
	return ((((r >> 3) & 31) << 11) | (((g >> 2) & 63) << 5) | ((b >> 3) & 31));
}

/* 把RGB数据按照屏幕的BPP调整 */
void *convertRGB2FB(int fh, unsigned char *rgbbuff, unsigned long count, int bpp, int *cpp)
{
	unsigned long i;
	void *fbbuff = NULL;
	unsigned char *c_fbbuff;
	unsigned short *s_fbbuff;
	unsigned int *i_fbbuff;

	switch(bpp)
	{
		case 8:
			//...
			break;
		case 15:
			//...
			break;
		case 16:
			*cpp = 2;
			s_fbbuff = (unsigned short *)malloc(count * sizeof(unsigned short));
			for(i = 0; i < count; i++)
				s_fbbuff[i] = make16color(rgbbuff[i * 3], rgbbuff[i * 3 + 1], rgbbuff[i * 3 + 2]);
			fbbuff = (void *)s_fbbuff;
			break;
		case 24:
			break;
		case 32:
			//...
			break;
		default:
			fprintf(stderr, "Unsupported video mode! You've got: %dbpp\n", bpp);
			exit(1);
	}
	return fbbuff;
}