求大神解答，得分多多
求大神注释一下句子
程序代码：#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/ipc.h>
#include "font_8x16.h"
#define Width 320 //LCD屏的宽度
#define Heigth 240 //LCD屏的高度
#define Start_x 8 //屏-左上角的起始坐标 x y
#define Start_y 8
#define End_x (Width - 8) //屏-左上角的起始坐标 x y
#define End_y (Heigth - 8)
int fk; //按键的文件描述符
char button_status[6];
int fp=0; //LCD屏的文件描述符
struct fb_var_screeninfo vinfo; //LCD可变参数结构体
struct fb_fix_screeninfo finfo; //LCD固定参数结构体
char *fbp = 0;
long screensize=0; //初始化屏幕大小为0
int s_x = 0, s_y = 0,id = 0; //屏幕的x y 坐标
//清屏
void clear_screen()
{
memset(fbp, 0xf8, screensize);
}
//绘制单个字符
void Draw_8X16(int x, int y, const unsigned char ch[])
{
int i = 0, j = 0;
unsigned char mask, buffer;
long location_tt;
location_tt = x * vinfo.bits_per_pixel / 8 + y *finfo.line_length;
for (i = 0; i < 16; i++)
{
mask = 0x80;
buffer = ch[i];
location_tt += finfo.line_length;
for (j = 0; j < 8; j ++)
{
if ((buffer & mask)) {
*(fbp +location_tt + j * vinfo.bits_per_pixel / 8) = 0;
*(fbp +location_tt + j * vinfo.bits_per_pixel / 8 + 1) = 0;
}
mask = mask >> 1;
}
}
s_x += 8;
}
//绘制单个汉字 16 * 16
void Draw_16X16(int x, int y, const unsigned char ch[])
{
int i = 0, j = 0;
unsigned char mask, buffer;
long location_tt;
location_tt = x * vinfo.bits_per_pixel / 8 + y * finfo.line_length;
for (i = 0; i < 16; i++)
{
mask = 0x80;
buffer = ch[i * 2];
location_tt += finfo.line_length;
for (j = 0; j < 8; j++) {
if ((buffer & mask)) {
*(fbp +location_tt + j * vinfo.bits_per_pixel / 8) = 0;
*(fbp +location_tt + j * vinfo.bits_per_pixel / 8 + 1) = 0;
}
mask = mask >> 1;
}
mask = 0x80;
buffer = ch[i * 2 + 1];
for (j = 0; j < 8; j++)
{
if ((buffer & mask))
{
*(fbp +location_tt + (8 + j) * vinfo.bits_per_pixel / 8) = 0;
*(fbp +location_tt + (8 + j) * vinfo.bits_per_pixel / 8 + 1) = 0;
}
mask = mask >> 1;
}
}
s_x += 16;
}
//判断是否换行 x坐标
int Is_next_line(int x)
{
if (x >= End_x)
return 1;
return 0;
}
//跳到下一行
int Next_line(int y)
{
//sleep(1);
y = y + 16;
s_y = y;
s_x = Start_x;
return y;
}
//判断是否换屏 y坐标
int Is_next_screen(int y)
{
if (y >= End_y - 8)
return 1;
return 0;
}
//清屏，跳到下一屏
void Next_screen()
{
int ret;
int i;
while (1)
{
ret = read(fk, button_status, 6);
if (ret < 0)
{
printf("read button status err\n");
}
//按键控制翻到下一页
if (button_status[0] == '1')
{
//清屏
clear_screen();
//s_x = Start_x;
s_y = Start_y;
break;
}
if (button_status[1] == '1'){
for(i=0;i<255;i++) ;
if (button_status[1] == '1'){
clear_screen();
printf("%d\n",id);
id=id-532;
s_y = Start_y;
break;}
}
}
// sleep(2);
}
//清屏，跳到上一屏
void UP_screen(unsigned int zf_index)
{
int ret;
//int i=0;
// unsigned char *buffer;
//unsigned char buf[16];
while (1)
{
ret = read(fk, button_status, 6);
if (ret < 0)
{
printf("read button status err\n");
}
//按键控制翻到上一页
if (button_status[1] == '1')
{
//清屏
clear_screen();
//s_x = Start_x;
//zf_index = buffer[i] * 16;
// memcpy(buf, (const void *)&Assic[zf_index], 16);
s_y=zf_index;
break;
}
}
// sleep(2);
}
//绘制一行字符
void Put_text_ch(int x, int y, int size, const unsigned char ch[])
{
int i = 0, j = 0;
unsigned char buffer[16];
for (i = 0; i < size; i++)
{
for (j = 0; j < 16; j++)
{
buffer[j] = ch[i * 16 + j];
}
if (i != 0)
x += 8;
if(Is_next_line(x))
{
y = Next_line(y);
x = s_x;
if (Is_next_screen(y))
{
Next_screen();
y = s_y;
}
}
Draw_8X16(x, y, buffer);
}
}
//绘制一行汉字
void Put_text_hz(int x, int y, int size, const unsigned char ch[])
{
int i = 0, j = 0;
unsigned char buffer[32];
for (i = 0; i < size; i++)
{
for (j = 0; j < 32; j++)
{
buffer[j] = ch[i * 32 + j];
}
if (i != 0)
x += 16;
if(Is_next_line(x))
{
y = Next_line(y);
x = s_x;
if (Is_next_screen(y))
{
Next_screen();
y = s_y;
}
}
Draw_16X16(x, y, buffer);
}
}
//打开LCD设备
void open_lcd()
{
//以可读可写的方式打开LCD设备
fp = open ("/dev/fb0",O_RDWR);
//错误冗余
if (fp < 0){
printf("Error : Can not open framebuffer device\n");
exit(1);
}
//在超级终端打印下面两句话
puts("hello, world.\n");
printf("open framebuffer device\n");
//获取屏幕相关参数
if (ioctl(fp,FBIOGET_FSCREENINFO,&finfo)){
printf("Error reading fixed information\n");
exit(2);
}
if (ioctl(fp,FBIOGET_VSCREENINFO,&vinfo)){
printf("Error reading variable information\n");
exit(3);
}
//计算屏幕缓冲区大小
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8; //单帧画面空间
printf("可见屏幕一行有多少个像素点：xres＝ %d\n", vinfo.xres);
printf("可见屏幕一列有多少个像素点：yres = %d\n", vinfo.yres);
printf("每个相似的位数即BPP: bits_per_pixel = %d\n", vinfo.bits_per_pixel);
/*这就是把fp所指的文件中从开始到screensize大小的内容给映射出来，得到一个指向这块空间的指针*/
fbp =(char *) mmap (0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fp,0);
if ((int) fbp == -1)
{
printf ("Error: failed to map framebuffer device to memory.\n");
exit (4);
}
printf("The Framebuffer device was mapped to memory successfully!\n");
}
//关闭LCD设备
void close_lcd()
{
munmap (fbp, screensize); /*解除映射*/
close (fp); /*关闭文件*/
}
//打开文本文件
int open_txt()
{
int fd_t;
fd_t = open("./1.txt",0);
if (fd_t < 0)
{
printf("txt can't open!\n");
return (-1);
}
return fd_t;
}
//关闭文本文件
void close_txt(int fd_t)
{
close(fd_t);
}
//计算文件总字节数
off_t cal_filesize(fd_t)
{
struct stat txt_stat;
off_t file_size_t = 0;
fstat(fd_t, &txt_stat);
file_size_t = txt_stat.st_size;
printf("file_size = %d\n", file_size_t);
return file_size_t;
}
int open_buttons()
{
int fk_t;
fk_t = open("/dev/buttons", O_RDWR);
if (fk_t < 0)
{
printf("can't open /dev/buttons\n");
return -1;
}
return fk_t;
}
void close_buttons(int fk_t)
{
close(fk_t);
}
int main(void)
{
int fd;
unsigned char *buffer;
off_t file_size = 0;
int k = 0;
unsigned int zf_index;
unsigned char buf[16];
fk = open_buttons();
open_lcd();
clear_screen();
s_x = Start_x;
s_y = Start_y;
//传过去的应该是文件路径
fd = open_txt();
if (fd < 0)
{
printf("txt can't open!\n");
return (-1);
}
//计算文件总字节数
file_size = cal_filesize(fd);
buffer = (unsigned char *)malloc(file_size);
memset(buffer, 0, file_size);
read(fd, buffer, file_size);
//printf("%s\n", buffer);
for (id = 0; id < file_size - 1; id++)
{
//判断文本中的当前字是不是换行符
if (buffer[id] == '\n')
{
//换行
Next_line(s_y);
//判断一下是不是又刚好是换屏
if (Is_next_screen(s_y))
Next_screen();
continue;
}
zf_index = buffer[id] * 16;
memcpy(buf, (const void *)&Assic[zf_index], 16);
/*for (k = 0; k < 16; k++)
printf("0x%x\t",buf[k]);
printf("\n");
*/
Put_text_ch(s_x, s_y, 1, buf);
}
close_txt(fd);
close_lcd();
close_buttons(fk);
return 0;
}
