嵌入式系统平台,读取framebuffer保存为png图片

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <fcntl.h>#include <sys/ioctl.h>#include <getopt.h>#include <sys/vt.h>#include <png.h>#include <zlib.h>#include <linux/fb.h>static int Blue = 0;static int Green = 1;static int Red = 2;static int Alpha = 3;int main(int argc, char**argv){struct fb_var_screeninfo fb_varinfo;int fd;int bitdepth, height, width;size_t buf_size;size_t buf_size1;unsigned char *inbuffer;unsigned char *outbuffer;/*fb_fix_screeninfo信息的设置*/memset(&fb_varinfo, 0, sizeof(struct fb_var_screeninfo));/*打开fb0设备节点*/fd = open("/dev/fb0",O_RDWR);if( fd == -1){printf("open dev fb0 error\n");return -1;}ioctl(fd,FBIOGET_VSCREENINFO, &fb_varinfo);printf("xres = %u yres = %u\n",fb_varinfo.xres,fb_varinfo.yres);bitdepth = (int)fb_varinfo.bits_per_pixel;width = (int)fb_varinfo.xres;height = (int)fb_varinfo.yres;/*存储raw文件*/Blue = fb_varinfo.blue.offset >> 3;Green = fb_varinfo.green.offset >> 3;Red = fb_varinfo.red.offset >> 3;Alpha = fb_varinfo.transp.offset >> 3;/*计算缓存大小*/buf_size = width * height * (bitdepth / 8);/*分配空间大小*/inbuffer = malloc(buf_size);if(inbuffer == NULL){printf("malloc error\n");return -1;}outbuffer = malloc(buf_size);if( outbuffer == NULL){printf("malloc error\n");return -1;}memset(inbuffer,0, buf_size);/*将原始数据存储到buf中*/if( read(fd, inbuffer, buf_size) != (ssize_t)buf_size){printf("not enough memory or data\n");return -1;}unsigned int i;for( i = 0; i < (unsigned int) height*width; i++){/* BLUE  = 0 */outbuffer[(i<<2)+Blue] = inbuffer[i*4+Blue];/* GREEN = 1 */outbuffer[(i<<2)+Green] = inbuffer[i*4+Green];/* RED   = 2 */outbuffer[(i<<2)+Red] = inbuffer[i*4+Red];/* ALPHA */outbuffer[(i<<2)+Alpha] = inbuffer[i*4+Alpha];}FILE *outfile = NULL;png_bytep row_pointers[height];outfile = fopen("screen.png","wb");for( i = 0; i < height; i++)row_pointers[i] = outbuffer + i*4*width;png_structp png_ptr;/**/png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp) NULL, (png_error_ptr) NULL, (png_error_ptr) NULL);if( !png_ptr){printf("png_create_write_struct error\n");return -1;}png_infop info_ptr;/*分配内存并初始化图像信息数据*/info_ptr  = png_create_info_struct(png_ptr);if(!info_ptr){printf("png_create_info_struct\n");png_destroy_write_struct(&png_ptr,&info_ptr);return -1;}if(setjmp(png_jmpbuf(png_ptr))){fclose(fd);png_destroy_write_struct(&png_ptr,&info_ptr);return -1;}/*设置输出控制,如果使用的是c的标准I/O流*/png_init_io(png_ptr,outfile);//png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);//bit_depth = 8;//color_type = PNG_COLOR_TYPE_RGB_ALPHA;//png_set_invert_alpha(png_ptr);//png_set_bgr(png_ptr);/**///png_set_IHDR(png_ptr,info_ptr,width,height,bit_depth,color_type, //PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);png_set_IHDR(png_ptr,info_ptr,width,height,8,PNG_COLOR_TYPE_RGB_ALPHA,PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);/*设置调色板的颜色集*///png_set_PLTE(png_ptr,info_ptr,palette,PNG_MAX_PALETTE_LENGTH);/*标注位(sBIT块)*///png_color_8 sig_bit;/*处理彩色图像*///sig_bit.red = true_red_bit_depth;//sig_bit.green = true_green_depth;//sig_bit.blue = true_blue_depth;/*如果这个图像有alpha通道*///sig_bit.alpha = true_alpha_bit_depth;//png_set_sBIT(png_str,info_ptr,&sig_bit);/*写入文件头信息(必需)*/png_write_info(png_ptr,info_ptr);png_write_image(png_ptr,row_pointers);png_write_end(png_ptr,info_ptr);//png_free(png_ptr,palette);//palette = NULL;png_destroy_write_struct(&png_ptr,&info_ptr);if( outfile != NULL){(void)fclose(outfile);}return 0;}

该部分代码实现了如何读取framebuffer文件,将/dev/fb0文件保存为png格式的

该部分代码上传了github上:

https://github.com/Guazhen/Framebuffer_shot/blob/master/famebuffer_shot_png.c

有不足的地方,希望大家指点出来啊