//第一：利用fb子系统画圆的方法与实现
//1、头文件信息 #include <sys/ioctl.h> #include <linux/fb.h> #include <stdio.h> #include <sys/types.h> #include <stdio.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/ioctl.h> #include <linux/fb.h> #include <string.h> #include <unistd.h> #include <stdlib.h> #define COLOR 0x0000ffff //定义lcd屏幕固定参数的变量 static struct fb_fix_screeninfo fix_info; //定义lcd屏幕可变参数的变量 static struct fb_var_screeninfo var_info; int main(int argc, char *argv[]) { int fd,ret,x,y,m,n; int *ptr; int *temp; //1、打开对应的设备节点 fd=open("/dev/fb0",O_RDWR); //2、利用ioclt函数传输对应的命令-固定参数 ret = ioctl(fd,FBIOGET_FSCREENINFO, &fix_info); if(ret < 0) { printf("error\r\n"); return -1; } //3、利用ioctl函数传递可变参数的命令 ret = ioctl(fd,FBIOGET_VSCREENINFO, &var_info); if(ret < 0) { printf("error\r\n"); return -1; } //4、输出获取到的参数信息--保存各自对应的结构体里面 printf("fix_info.smem_len = %d, fix_info.line_length = %d, var_info.xres = %d, var_info.yres = %d, var_info.bits_per_pixel = %d\n", \ fix_info.smem_len, fix_info.line_length, var_info.xres, var_info.yres, var_info.bits_per_pixel); ptr = (int *)mmap(NULL,fix_info.smem_len,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0); temp = ptr; for(x = 0;x < 800;x++) { for(y = 0;y < 1280;y++) { *temp = COLOR; temp++; //usleep(100000); } } temp = ptr; for(x = 0;x < 1280;x++)//400,640 { for(y = 0;y < 800;y++) { m = abs(x-640)*abs(x-640); n = abs(y-400)*abs(y-400); if((m+n)<201*201 && (m+n >199*199)) { *(temp+x*800+y) = 0x00ff0000; }; } } return 0; }
//第二个：图片循环显示的方法
#include<stdio.h> #include<setjmp.h> #include<jpeglib.h> #include<stdio.h> #include<sys/mman.h> #include<sys/types.h> #include<sys/stat.h> #include<unistd.h> #include<sys/types.h> #include<sys/stat.h> #include<fcntl.h> #include<sys/ioctl.h> #include<linux/fb.h> #include<string.h> #include<stdlib.h> int main(int argc,char *argv[]) { int fd_fb; int ret; int x,y; int* pfile; int color=0; struct fb_fix_screeninfo fix_info; struct fb_var_screeninfo var_info; fd_fb=open("/dev/fb0",O_RDWR); ioctl(fd_fb,FBIOGET_FSCREENINFO,&fix_info); ioctl(fd_fb,FBIOGET_VSCREENINFO,&var_info); pfile=(int*)mmap(NULL,fix_info.smem_len,PROT_READ|PROT_WRITE,MAP_SHARED,fd_fb,0); system("ls ./pic > temp.txt"); FILE *temp_fb=fopen("temp.txt","rb"); int num; char temp[100][30]={0}; char *EO; num=0; do { char pwd[20]={0}; EO=fgets(pwd,sizeof(pwd)-1,temp_fb); if(EO!=NULL) { strncat(temp[num],"./pic/",strlen("./pic/")); strncat(temp[num],pwd,strlen(pwd)-1); num++; } }while(EO!=NULL); fclose(temp_fb); struct jpeg_decompress_struct cinfo; struct jpeg_error_mgr jerr; cinfo.err=jpeg_std_error(&jerr);//一旦出错，会将错误信息放到这里 jpeg_create_decompress(&cinfo);//初始化核心结构体 for(y=0;y<num;y++) { FILE *infile=NULL; printf("%d\t%s\r\n",y,temp[y]); infile=fopen((char *)temp[y],"rb"); if(infile==NULL) { perror("error"); break; } jpeg_stdio_src(&cinfo,infile);//绑定核心结构体和要展示的图片 jpeg_read_header(&cinfo,TRUE); cinfo.scale_num=1; cinfo.scale_denom=1; cinfo.out_color_space=JCS_RGB; //5.解压缩图片 jpeg_start_decompress(&cinfo); //6.读取数据并且上屏操作 unsigned char*buffer;//这个变量是读取jpeg图片的数据 buffer=(unsigned char*)malloc(cinfo.output_width*cinfo.output_components);//变量使用空间的大小--800*3行的大小2400 while(cinfo.output_scanline<cinfo.output_height) { memset(buffer,0,sizeof(buffer)); jpeg_read_scanlines(&cinfo,&buffer,1); for(x=0;x<cinfo.output_width;x++) { switch(cinfo.output_components) { case 1: color=buffer[0+x*1]<<16|buffer[1+x*1]<<8|buffer[2+x*1]<<0; break; case 3: color=buffer[0+x*3]<<16|buffer[1+x*3]<<8|buffer[2+x*3]<<0; break; case 4: color=buffer[0+x*4]<<24|buffer[1+x*4]<<16|buffer[2+x*4]<<8|buffer[3+x*4]<<0; break; } *(pfile+x+800*(cinfo.output_scanline-1))=color; color=0; } } //7.完成解码 jpeg_finish_decompress(&cinfo); free(buffer); fclose(infile);//文件流指针，需要收回一下 sleep(5); } //8.释放空间 jpeg_destroy_decompress(&cinfo); munmap(pfile,fix_info.smem_len); close(fd_fb); return 0; }
第三：图片循环显示的方法（二）
#include <stdio.h> #include <setjmp.h> #include <jpeglib.h> #include <stdio.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/ioctl.h> #include <linux/fb.h> #include <string.h> #include <stdlib.h> char *file; int num = 1; int main(int argc, char *argv[]) { int fd; int ret; int x; int *pfile; int color = 0; char file[20]; struct fb_fix_screeninfo fix_info; struct fb_var_screeninfo var_info; //打开lcd设备 fd = open("/dev/fb0", O_RDWR); if(fd < 0) { perror("open"); return -1; } //获取lcd的基础信息 ret = ioctl(fd, FBIOGET_FSCREENINFO, &fix_info); if(ret < 0) { perror("ioctl_fix"); return -1; } ret = ioctl(fd, FBIOGET_VSCREENINFO, &var_info); if(ret < 0) { perror("ioctl_fix"); return -1; } printf("fix_info.smem_len = %d, fix_info.line_length = %d, var_info.xres = %d, var_info.yres = %d, var_info.bits_per_pixel = %d\n", \ fix_info.smem_len, fix_info.line_length, var_info.xres, var_info.yres, var_info.bits_per_pixel); pp: //映射显存空间 pfile = (int *)mmap(NULL, fix_info.smem_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if(pfile == MAP_FAILED) { perror("mmap"); return -1; } //jpeg源码处理jpeg图片步骤 //1.定义核心结构体并初始化 struct jpeg_decompress_struct cinfo; struct jpeg_error_mgr jerr; cinfo.err = jpeg_std_error(&jerr); //一旦出错，会将错误信息放到这里 jpeg_create_decompress(&cinfo);//初始化核心结构体 FILE* infile; sprintf(file,"%d.jpg",num); //2.绑定图片资源 if ((infile = fopen(file, "rb")) == NULL) { // file指向自己的jpg文件的绝对路径 fprintf(stderr, "open failed\n"); return -1; } jpeg_stdio_src(&cinfo, infile);//绑定核心结构体和要展示的图片 //3.读取图片的基础信息 jpeg_read_header(&cinfo, TRUE); //注意：：cinfo.image_width和cinfo.output_width是两个数据 //注意：：cinfo.image_width和cinfo.output_width是两个数据 //注意：：cinfo.image_width和cinfo.output_width是两个数据 printf("cinfo.image_width = %d, cinfo.image_height = %d, cinfo.num_components = %d\n", \ cinfo.image_width, cinfo.image_height, cinfo.num_components); //4.设置解压缩的参数---注意：如果使用了参数，则图片信息会发生变化，要使用cinfo.output*这类的数据 //开始的这两参数是决定图片的大小可以等比例缩放 ----JCS_GRAYSCALE--灰度显示命令 cinfo.scale_num=1; cinfo.scale_denom=1; //cinfo.out_color_space=JCS_GRAYSCALE; cinfo.out_color_space=JCS_RGB; //5.解压缩图片 jpeg_start_decompress(&cinfo); printf("cinfo.output_width = %d, cinfo.output_height = %d, cinfo.output_components = %d,cinfo.output_scanline=%d\n", \ cinfo.output_width, cinfo.output_height, cinfo.output_components,cinfo.output_scanline); //6.读取数据并且上屏操作 //6.读取解压缩后的数据并上屏 //官方的操作 // JSAMPARRAY buffer; // unsigned int row_stride = cinfo.output_width * cinfo.output_components; // buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1); //常规操作 unsigned char *buffer; //这个变量是读取jpeg图片的数据 buffer = (unsigned char *)malloc(cinf o.output_width*cinfo.output_components); //变量使用空间的大小--800*3 行的大小2400 if(cinfo.output_components == 4) //如果图片为4通道时--跟随颜色分量的 RGB8888 { while(cinfo.output_scanline < cinfo.output_height)//cinfo.output_scanline会随着jpeg_read_scanlines的触发而增1 { memset(buffer, 0, sizeof(buffer)); jpeg_read_scanlines(&cinfo, &buffer, 1);//如果是官方操作，buffer是一个二维指针变量，这里不用取址符 for(x = 0; x < cinfo.output_width; x++) { //进行数据整合 color = buffer[0+x*4] << 24 | buffer[1+x*4] << 16 | buffer[2+x*4] << 8 | buffer[3+x*4] << 0; *(pfile + x + 800*(cinfo.output_scanline-1)) = color; color = 0; } } }else if(cinfo.output_components == 3) { //如果图片为3通道时--屏幕 while(cinfo.output_scanline < cinfo.output_height)//cinfo.output_scanline会随着jpeg_read_scanlines的触发而增1 { memset(buffer, 0, sizeof(buffer)); jpeg_read_scanlines(&cinfo, &buffer, 1);//如果是官方操作，buffer是一个二维指针变量，这里不用取址符 for(x = 0; x < cinfo.output_width; x++) { color = buffer[0+x*3] << 16 | buffer[1+x*3] << 8 | buffer[2+x*3] << 0; //RGB888 *(pfile + x + 800*(cinfo.output_scanline-1)) = color; //清楚一下，color里面原来的图像数据 color = 0; } //printf("cinfo.output_scanline = %d\n", cinfo.output_scanline); } }else if(cinfo.output_components == 1) { //如果图片为1通道，也就是选择灰白色时 while(cinfo.output_scanline < cinfo.output_height)//cinfo.output_scanline会随着jpeg_read_scanlines的触发而增1 { memset(buffer, 0, sizeof(buffer)); jpeg_read_scanlines(&cinfo, &buffer, 1);//如果是官方操作，buffer是一个二维指针变量，这里不用取址符 for(x = 0; x < cinfo.output_width; x++) { //灰度图像 buffer[0]---高位 数据整合 buffer[0] buffer[1]buffer[2] ----buffer[1]buffer[2]buffer[3] color = buffer[0+x*1] << 16 | buffer[1+x*1] << 8 | buffer[2+x*1] << 0; *(pfile + x + 800*(cinfo.output_scanline-1)) = color; color = 0; } //printf("cinfo.output_scanline = %d\n", cinfo.output_scanline); } } sleep(3); num++; if(num == 3) { num = 1; } //7.完成解码 jpeg_finish_decompress(&cinfo); //8.释放空间 free(buffer); fclose(infile); //文件流指针，需要收回一下 jpeg_destroy_decompress(&cinfo); munmap(pfile, fix_info.smem_len); goto pp; close(fd); return 0; } //aarch64-linux-gnu-gcc a.c -o main -I/home/fang/work/armlib/include -L/home/fang/work/armlib/lib -ljpeg
