实现ARM平台开发板开机动画+切换界面

 * @function name:	read_JPEG_file
 * @brief        : 实现开机动画+切换界面
 * @param  	  : * filename
  				  : start_x
  				  : start_y
 * @retval       :int
 * @date         :2024/05/14
 * @version      :1.0  
 * @note         :本函数要在移植好JPEG库的前提下使用
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <linux/input.h>



/*
 * Include file for users of JPEG library.
 * You will need to have included system headers that define at least
 * the typedefs FILE and size_t before you can include jpeglib.h.
 * (stdio.h is sufficient on ANSI-conforming systems.)
 * You may also wish to include "jerror.h".
 */

#include "jpeglib.h"


int * lcd_mp;


//成功返回1 失败返回0
int read_JPEG_file (char * filename,int start_x,int start_y)
{
  /* This struct contains the JPEG decompression parameters and pointers to
   * working space (which is allocated as needed by the JPEG library).
   */
  struct jpeg_decompress_struct cinfo;
  /* We use our private extension JPEG error handler.
   * Note that this struct must live as long as the main JPEG parameter
   * struct, to avoid dangling-pointer problems.
   */
  struct jpeg_error_mgr jerr;
  /* More stuff */
  FILE * infile;			/* source file */
  unsigned char * buffer;		/* Output row buffer */
  int row_stride;			/* physical row width in output buffer */

  /* In this example we want to open the input file before doing anything else,
   * so that the setjmp() error recovery below can assume the file is open.
   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
   * requires it in order to read binary files.
   */

  if ((infile = fopen(filename, "rb")) == NULL) {
    fprintf(stderr, "can't open %s\n", filename);
    return 0;
  }

  /* Step 1: allocate and initialize JPEG decompression object */

  /* We set up the normal JPEG error routines, then override error_exit. */
  cinfo.err = jpeg_std_error(&jerr);

  /* Now we can initialize the JPEG decompression object. */
  jpeg_create_decompress(&cinfo);

  /* Step 2: specify data source (eg, a file) */

  jpeg_stdio_src(&cinfo, infile);

  /* Step 3: read file parameters with jpeg_read_header() */

  (void) jpeg_read_header(&cinfo, TRUE);
  /* We can ignore the return value from jpeg_read_header since
   *   (a) suspension is not possible with the stdio data source, and
   *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
   * See libjpeg.txt for more info.
   */

  /* Step 4: set parameters for decompression */

  /* In this example, we don't need to change any of the defaults set by
   * jpeg_read_header(), so we do nothing here.
   */

  /* Step 5: Start decompressor */

  (void) jpeg_start_decompress(&cinfo);
  /* We can ignore the return value since suspension is not possible
   * with the stdio data source.
   */

  /* We may need to do some setup of our own at this point before reading
   * the data.  After jpeg_start_decompress() we have the correct scaled
   * output image dimensions available, as well as the output colormap
   * if we asked for color quantization.
   * In this example, we need to make an output work buffer of the right size.
   */ 
  /* JSAMPLEs per row in output buffer */
  row_stride = cinfo.output_width * cinfo.output_components;  //计算一行的大小

  /* Make a one-row-high sample array that will go away when done with image */
  buffer = calloc(1,row_stride);

  /* Step 6: while (scan lines remain to be read) */
  /*           jpeg_read_scanlines(...); */

  /* Here we use the library's state variable cinfo.output_scanline as the
   * loop counter, so that we don't have to keep track ourselves.
   */
  int data = 0;

  while (cinfo.output_scanline < cinfo.output_height) 
  {
    /* jpeg_read_scanlines expects an array of pointers to scanlines.
     * Here the array is only one element long, but you could ask for
     * more than one scanline at a time if that's more convenient.
     */
    (void) jpeg_read_scanlines(&cinfo, &buffer, 1); //从上到下，从左到右  RGB RGB RGB RGB 
  	
  	for (int i = 0; i < cinfo.output_width; ++i)  //012 345
  	{
  		data |= buffer[3*i]<<16;	//R
		data |= buffer[3*i+1]<<8;	//G
		data |= buffer[3*i+2];  	//B 

		//把像素点写入到LCD的指定位置
		lcd_mp[800*start_y + start_x + 800*(cinfo.output_scanline-1) + i] = data;

		data = 0;
  	}
  
  }

  /* Step 7: Finish decompression */

  (void) jpeg_finish_decompress(&cinfo);
  /* We can ignore the return value since suspension is not possible
   * with the stdio data source.
   */

  /* Step 8: Release JPEG decompression object */

  /* This is an important step since it will release a good deal of memory. */
  jpeg_destroy_decompress(&cinfo);

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  fclose(infile);

  /* At this point you may want to check to see whether any corrupt-data
   * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
   */

  /* And we're done! */
  return 1;
}


int main(int argc, char const *argv[])
{
	//1.打开LCD   open  
	int lcd_fd = open("/dev/fb0",O_RDWR);
    if(-1 == lcd_fd)
    {
        printf("open failed\n");
        return -1;
    }

	//2.对LCD进行内存映射  mmap
	lcd_mp = (int *)mmap(NULL,800*480*4,PROT_READ|PROT_WRITE,MAP_SHARED,lcd_fd,0);
	//3.显示开机动画
	char gif_path[512] ={0}; 
	
	for (int i = 0; i < 22; ++i)
	{
		sprintf(gif_path,"./gif2/Frame%d.jpg",i);  //构造jpg图片的路径
		read_JPEG_file (gif_path,0,0);			  //在LCD上显示
		usleep(1000*20);						  //FPS = 50HZ
	}	
    read_JPEG_file ("R-C.jpg",0,0);	//显示主界面
    read_JPEG_file ("./demo/1.jpg",200,380);	//显示登录按钮
    read_JPEG_file ("./demo/2.jpg",600,380);	//显示退出按钮
    //1.打开触摸屏   
	int ts_fd = open("/dev/input/event0",O_RDWR);

	//2.读取输入设备的信息
	struct input_event ts_event;

    int cnt = 0; 
    int x,y;

	while(1)
	{
        
		read(ts_fd,&ts_event,sizeof(ts_event));
        
		//3.分析读取的设备信息 (type + code + value)
		if (ts_event.type == EV_ABS) //说明是触摸屏
		{
			if (ts_event.code ==  ABS_X) //说明是X轴
			{
				cnt++;
				x = ts_event.value * 800 / 1024;//等比例缩放
			}
			if (ts_event.code ==  ABS_Y) //说明是Y轴
			{
				cnt++;
				y = ts_event.value * 480 / 600;//等比例缩放
			}
			if(cnt >= 2)
			{
                if(x >= 200 && x <= 300 && y >= 380 && y <= 430)//登录按钮的触摸位置
                {
                    read_JPEG_file ("./demo/5.jpg",0,0);	//显示系统主界面
                    read_JPEG_file ("./demo/3.jpg",720,0);	//显示返回按钮     
                          
                }
                else if(x >= 720 && x <= 800 && y >= 0 && y <= 80)//返回按钮的触摸位置
                {
                    read_JPEG_file ("R-C.jpg",0,0);	//显示主界面
                    read_JPEG_file ("./demo/1.jpg",200,380);	//显示登录按钮
                    read_JPEG_file ("./demo/2.jpg",600,380);	//显示退出按钮     
                }
				printf("x = %d\t", x); //输出X轴坐标
				printf("y = %d\n", y); //输出Y轴坐标
				cnt=0;
                
			}
            
		}
        

	}

  
	
	//4.关闭触摸屏
	close(ts_fd);

	return 0;
}