// SPDX-License-Identifier: GPL-2.1-or-later /* * Copyright (C) 2009-2012 Cyril Hrubis <metan@ucw.cz> */ /* Gets an image from v4l2 device. */ #include <string.h> #include <errno.h> #include <stdio.h> #include <gfxprim.h> static int get_image(const char *filename, gp_grabber *grabber) { /* turn on grabber */ if (gp_grabber_start(grabber)) { fprintf(stderr, "Failed to start grabber\n"); return 1; } /* throw away first frame, it's usually wrong */ while (!gp_grabber_poll(grabber)) usleep(100000); while (!gp_grabber_poll(grabber)) usleep(100000); /* save image */ if (gp_save_jpg(grabber->frame, filename, NULL)) { fprintf(stderr, "Failed to save image '%s': %s", filename, strerror(errno)); return 1; } /* turn off grabber */ if (gp_grabber_stop(grabber)) { fprintf(stderr, "Failed to start grabber\n"); return 1; } return 0; } int main(int argc, char *argv[]) { const char *v4l2_device = "/dev/video0"; const char *image_filename = "frame.jpg"; unsigned int w = 640, h = 480; int secs = 0; int opt; while ((opt = getopt(argc, argv, "d:hH:o:W:l:s:")) != -1) { switch (opt) { case 'o': image_filename = optarg; break; case 'd': v4l2_device = optarg; break; case 'W': w = atoi(optarg); break; case 'H': h = atoi(optarg); break; case 's': secs = atoi(optarg); break; case 'l': gp_set_debug_level(atoi(optarg)); break; case 'h': printf("Usage; %s opts\n", argv[0]); printf("-o output image file, default is 'frame.jpg'\n" "-d v4l2 device name (default is '/dev/video0'\n" "-W output image width, default is 640\n" "-H output image height, default is 480\n" "-l sets GFXprim debug level (default is 0)\n" "-s take image every s seconds (the images are stored as frameX.jpg)\n" "-h prints this help\n"); return 0; break; default: fprintf(stderr, "Invalid paramter '%c'\n", opt); return 1; } } gp_grabber *grabber = gp_grabber_v4l2_init(v4l2_device, w, h); if (grabber == NULL) { fprintf(stderr, "Failed to initalize grabber '%s': %s\n", v4l2_device, strerror(errno)); return 1; } if (secs == 0) { get_image(image_filename, grabber); gp_grabber_exit(grabber); return 0; } int i = 0; for (;;) { char buf[128]; snprintf(buf, sizeof(buf), "frame%03i.jpg", i++); if (get_image(buf, grabber)) { fprintf(stderr, "Failed to get image, exitting...\n"); return 1; } sleep(secs); } return 0; }
Grabbers (v4l2) Examples
Simple grabber example that saves images taken from v4l2 device.
More sophisticated example utilizing v4l2 device and backends.
// SPDX-License-Identifier: GPL-2.1-or-later /* * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz> */ /* Simple V4L2 grabber interactive example. */ #include <errno.h> #include <string.h> #include <stdio.h> #include <gfxprim.h> static void save_image(gp_pixmap *p) { static unsigned int counter; char fname[256]; snprintf(fname, sizeof(fname), "screenshot%u.jpg", counter++); gp_save_jpg(p, fname, NULL); } int main(int argc, char *argv[]) { gp_backend *backend; gp_grabber *grabber; const char *v4l2_device = "/dev/video0"; unsigned int w = 640, h = 480; int mode = 0; int opt; while ((opt = getopt(argc, argv, "d:hH:W:l:")) != -1) { switch (opt) { case 'd': v4l2_device = optarg; break; case 'W': w = atoi(optarg); break; case 'H': h = atoi(optarg); break; case 'l': gp_set_debug_level(atoi(optarg)); break; case 'h': printf("Usage; %s opts\n", argv[0]); printf("-d v4l2 device name (default is '/dev/video0'\n" "-W output image width, default is 640\n" "-H output image height, default is 480\n" "-l sets GFXprim debug level (default is 0)\n" "-h prints this help\n"); return 0; break; default: fprintf(stderr, "Invalid paramter '%c'\n", opt); return 1; } } grabber = gp_grabber_v4l2_init(v4l2_device, w, h); if (grabber == NULL) { fprintf(stderr, "Failed to initalize grabber '%s': %s\n", v4l2_device, strerror(errno)); return 1; } backend = gp_x11_init(NULL, 0, 0, grabber->frame->w, grabber->frame->h, "V4L2", 0); if (backend == NULL) { gp_grabber_exit(grabber); return 1; } if (gp_grabber_start(grabber)) { fprintf(stderr, "Failed to start grabber\n"); gp_backend_exit(backend); gp_grabber_exit(grabber); return 1; } printf("Press SPACE to change mode and Q to exit.\n"); for (;;) { if (gp_grabber_poll(grabber) > 0) { gp_pixmap *res, *img = grabber->frame; switch (mode) { case 0: res = img; break; case 1: // gp_filter_edge_prewitt(img, &res, NULL, NULL); gp_filter_edge_sobel(img, &res, NULL, NULL); break; case 2: gp_filter_gaussian_blur(img, img, 1, 1, NULL); res = gp_filter_floyd_steinberg_alloc(img, GP_PIXEL_G2, NULL); break; } unsigned int c_x = (backend->pixmap->w - res->w) / 2; unsigned int c_y = (backend->pixmap->h - res->h) / 2; gp_blit_clipped(res, 0, 0, res->w, res->h, backend->pixmap, c_x, c_y); gp_backend_flip(backend); if (mode) gp_pixmap_free(res); } usleep(1000); gp_backend_poll(backend); /* Read and parse events */ gp_event *ev; while ((ev = gp_backend_get_event(backend))) { switch (ev->type) { case GP_EV_KEY: /* ignore key up events */ if (!ev->code) continue; switch (ev->key.key) { case GP_KEY_ESC: case GP_KEY_Q: goto exit; break; case GP_KEY_S: save_image(backend->pixmap); break; case GP_KEY_SPACE: mode++; if (mode > 2) mode = 0; break; } break; case GP_EV_SYS: switch (ev->code) { case GP_EV_SYS_RESIZE: gp_backend_resize_ack(backend); gp_fill(backend->pixmap, 0); break; case GP_EV_SYS_QUIT: goto exit; break; } break; } } } exit: gp_backend_exit(backend); gp_grabber_exit(grabber); return 0; }