/***************************************************************************** * This file is part of gfxprim library. * * * * Gfxprim is free software; you can redistribute it and/or * * modify it under the terms of the GNU Lesser General Public * * License as published by the Free Software Foundation; either * * version 2.1 of the License, or (at your option) any later version. * * * * Gfxprim is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * * Lesser General Public License for more details. * * * * You should have received a copy of the GNU Lesser General Public * * License along with gfxprim; if not, write to the Free Software * * Foundation, Inc., 51 Franklin Street, Fifth Floor, * * Boston, MA 02110-1301 USA * * * * Copyright (C) 2009-2012 Cyril Hrubis <metan@ucw.cz> * * * *****************************************************************************/ /* Gets an image from v4l2 device. */ #include <string.h> #include <errno.h> #include <GP.h> static int get_image(const char *filename, GP_Grabber *grabber) { /* turn on grabber */ if (GP_GrabberStart(grabber)) { fprintf(stderr, "Failed to start grabber\n"); return 1; } /* throw away first frame, it's usually wrong */ while (!GP_GrabberPoll(grabber)) usleep(100000); while (!GP_GrabberPoll(grabber)) usleep(100000); /* save image */ if (GP_SaveJPG(grabber->frame, filename, NULL)) { fprintf(stderr, "Failed to save image '%s': %s", filename, strerror(errno)); return 1; } /* turn off grabber */ if (GP_GrabberStop(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_SetDebugLevel(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_GrabberV4L2Init(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_GrabberExit(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.
/***************************************************************************** * This file is part of gfxprim library. * * * * Gfxprim is free software; you can redistribute it and/or * * modify it under the terms of the GNU Lesser General Public * * License as published by the Free Software Foundation; either * * version 2.1 of the License, or (at your option) any later version. * * * * Gfxprim is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * * Lesser General Public License for more details. * * * * You should have received a copy of the GNU Lesser General Public * * License along with gfxprim; if not, write to the Free Software * * Foundation, Inc., 51 Franklin Street, Fifth Floor, * * Boston, MA 02110-1301 USA * * * * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz> * * * *****************************************************************************/ /* Simple V4L2 grabber interactive example. */ #include <errno.h> #include <string.h> #include <GP.h> int main(int argc, char *argv[]) { GP_Backend *backend; GP_Grabber *grabber; const char *v4l2_device = "/dev/video0"; unsigned int w = 320, h = 240; 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_SetDebugLevel(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_GrabberV4L2Init(v4l2_device, w, h); if (grabber == NULL) { fprintf(stderr, "Failed to initalize grabber '%s': %s\n", v4l2_device, strerror(errno)); return 1; } backend = GP_BackendX11Init(NULL, 0, 0, grabber->frame->w, grabber->frame->h, "V4L2", 0); if (backend == NULL) { GP_GrabberExit(grabber); return 1; } if (GP_GrabberStart(grabber)) { fprintf(stderr, "Failed to start grabber\n"); GP_BackendExit(backend); GP_GrabberExit(grabber); return 1; } printf("Press SPACE to change mode and Q to exit.\n"); for (;;) { if (GP_GrabberPoll(grabber) > 0) { GP_Context *res, *img = grabber->frame; switch (mode) { case 0: res = img; break; case 1: // GP_FilterEdgePrewitt(img, &res, NULL, NULL); GP_FilterEdgeSobel(img, &res, NULL, NULL); break; case 2: GP_FilterGaussianBlur(img, img, 1, 1, NULL); res = GP_FilterFloydSteinbergAlloc(img, GP_PIXEL_G2, NULL); break; } GP_Blit_Clipped(res, 0, 0, res->w, res->h, backend->context, 0, 0); GP_BackendFlip(backend); if (mode) GP_ContextFree(res); } usleep(1000); GP_BackendPoll(backend); /* Read and parse events */ GP_Event ev; while (GP_BackendGetEvent(backend, &ev)) { switch (ev.type) { case GP_EV_KEY: /* ignore key up events */ if (!ev.code) continue; switch (ev.val.key.key) { case GP_KEY_ESC: case GP_KEY_Q: GP_BackendExit(backend); GP_GrabberExit(grabber); return 0; break; case GP_KEY_SPACE: mode++; if (mode > 2) mode = 0; break; } } } } GP_BackendExit(backend); return 0; }