嵌入式

嵌入式linux通用截图工具

2019-07-12 22:00发布

站内文章 / 嵌入式Linux
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嵌入式linux通用截图工具
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文章出处：http://www.limodev.cn/blog
作者联系方式：李先静 为了截几张图片给broncho的A1做宣传，昨天写了一个截图工具。这个工具与其它截图工具不同的是，它不基于任何具体的GUI，直接从framebuffer中截图，然后保存为jpeg图片，所以适用于任何嵌入式linux设备。 o 打开framebuffer static int fb_open(struct FB *fb, const char* fbfilename) { fb->fd = open(fbfilename, O_RDWR); if (fb->fd < 0) { fprintf(stderr, "can't open %s/n", fbfilename); return -1; }   if (ioctl(fb->fd, FBIOGET_FSCREENINFO, &fb->fi) < 0) goto fail; if (ioctl(fb->fd, FBIOGET_VSCREENINFO, &fb->vi) < 0) goto fail;   fb->bits = mmap(0, fb_size(fb), PROT_READ | PROT_WRITE, MAP_SHARED, fb->fd, 0); if (fb->bits == MAP_FAILED) goto fail;   return 0; fail: printf("%s is not a framebuffer./n", fbfilename); close(fb->fd);   return -1; } o 读取数据并写入jpeg static int snap(const char * filename, int quality, struct FB* fb) { int row_stride = 0; FILE * outfile = NULL; JSAMPROW row_pointer[1] = {0}; struct jpeg_error_mgr jerr = {0}; struct jpeg_compress_struct cinfo = {0};   cinfo.err = jpeg_std_error(&jerr); jpeg_create_compress(&cinfo);   if ((outfile = fopen(filename, "wb+")) == NULL) { fprintf(stderr, "can't open %s/n", filename);   return -1; }   jpeg_stdio_dest(&cinfo, outfile); cinfo.image_width = fb_width(fb); cinfo.image_height = fb_height(fb); cinfo.input_components = 3; cinfo.in_color_space = JCS_RGB; jpeg_set_defaults(&cinfo); jpeg_set_quality(&cinfo, quality, TRUE); jpeg_start_compress(&cinfo, TRUE);   row_stride = fb_width(fb) * 2; JSAMPLE* image_buffer = malloc(3 * fb_width(fb));   while (cinfo.next_scanline < cinfo.image_height) { int i = 0; unsigned short* line = fb->bits + cinfo.next_scanline * fb_width(fb); for(i = 0; i < fb_width(fb); i++) { int offset = i * 3; unsigned short color = line[i]; unsigned char r = ((color >> 11) & 0xff) << 3; unsigned char g = ((color >> 5) & 0xff) << 2; unsigned char b = (color & 0xff )<< 3; image_buffer[offset] = r; image_buffer[offset + 1] = g; image_buffer[offset + 2] = b; }   row_pointer[0] = image_buffer; (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); }   jpeg_finish_compress(&cinfo); fclose(outfile);   jpeg_destroy_compress(&cinfo);   return 0; } o 主函数 int main(int argc, char* argv[]) { struct FB fb = {0}; const char* filename = NULL; const char* fbfilename = NULL;   if(argc != 3) { printf("/nusage: %s [jpeg] [framebuffer]/n", argv[0]); printf("-----------------------------------------/n"); printf("Powered by broncho(www.broncho.cn)/n"); return 0; }   filename = argv[1]; fbfilename = argv[2]; if (fb_open(&fb, fbfilename) == 0) { snap(filename, 100, &fb); fb_close(&fb); }   return 0; } 完整代码请到这里下载。

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