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@@ -0,0 +1,435 @@
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+#include <errno.h>
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+#include <fcntl.h>
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+#include <linux/videodev2.h>
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+#include <sys/ioctl.h>
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+#include <sys/mman.h>
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+#include <asm/errno.h>
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+#include <gtk/gtk.h>
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+
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+#define CLEAR(x) memset(&(x), 0, sizeof(x))
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+
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+enum io_method {
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+ IO_METHOD_READ,
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+ IO_METHOD_MMAP,
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+ IO_METHOD_USERPTR,
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+};
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+
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+struct buffer {
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+ void *start;
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+ size_t length;
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+};
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+
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+
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+struct buffer *buffers;
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+static unsigned int n_buffers;
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+static char *dev_name;
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+static enum io_method io = IO_METHOD_MMAP;
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+static int force_format_width = 640;
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+static int force_format_height = 480;
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+GObject *preview_image;
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+
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+
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+static int xioctl(int fd, int request, void *arg) {
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+ int r;
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+ do r = ioctl(fd, request, arg);
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+ while (-1 == r && EINTR == errno);
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+ return r;
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+}
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+
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+static void errno_exit(const char *s) {
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+ fprintf(stderr, "%s error %d, %s\\n", s, errno, strerror(errno));
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+ exit(EXIT_FAILURE);
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+}
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+
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+static void start_capturing(int fd) {
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+ unsigned int i;
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+ enum v4l2_buf_type type;
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+
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+ switch (io) {
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+ case IO_METHOD_READ:
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+ /* Nothing to do. */
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+ break;
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+
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+ case IO_METHOD_MMAP:
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+ for (i = 0; i < n_buffers; ++i) {
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+ struct v4l2_buffer buf;
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+
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+ CLEAR(buf);
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+ buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ buf.memory = V4L2_MEMORY_MMAP;
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+ buf.index = i;
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+
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+ if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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+ errno_exit("VIDIOC_QBUF");
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+ }
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+ type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
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+ errno_exit("VIDIOC_STREAMON");
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+ break;
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+
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+ case IO_METHOD_USERPTR:
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+ for (i = 0; i < n_buffers; ++i) {
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+ struct v4l2_buffer buf;
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+
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+ CLEAR(buf);
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+ buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ buf.memory = V4L2_MEMORY_USERPTR;
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+ buf.index = i;
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+ buf.m.userptr = (unsigned long) buffers[i].start;
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+ buf.length = buffers[i].length;
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+
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+ if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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+ errno_exit("VIDIOC_QBUF");
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+ }
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+ type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
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+ errno_exit("VIDIOC_STREAMON");
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+ break;
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+ }
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+}
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+
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+static void init_mmap(int fd) {
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+ struct v4l2_requestbuffers req;
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+
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+ CLEAR(req);
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+
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+ req.count = 4;
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+ req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ req.memory = V4L2_MEMORY_MMAP;
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+
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+ if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
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+ if (EINVAL == errno) {
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+ fprintf(stderr, "%s does not support "
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+ "memory mappingn", dev_name);
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+ exit(EXIT_FAILURE);
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+ } else {
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+ errno_exit("VIDIOC_REQBUFS");
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+ }
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+ }
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+
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+ if (req.count < 2) {
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+ fprintf(stderr, "Insufficient buffer memory on %s\\n",
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+ dev_name);
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+ exit(EXIT_FAILURE);
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+ }
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+
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+ buffers = calloc(req.count, sizeof(*buffers));
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+
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+ if (!buffers) {
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+ fprintf(stderr, "Out of memory\\n");
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+ exit(EXIT_FAILURE);
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+ }
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+
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+ for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
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+ struct v4l2_buffer buf;
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+
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+ CLEAR(buf);
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+
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+ buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ buf.memory = V4L2_MEMORY_MMAP;
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+ buf.index = n_buffers;
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+
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+ if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
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+ errno_exit("VIDIOC_QUERYBUF");
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+
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+ buffers[n_buffers].length = buf.length;
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+ buffers[n_buffers].start =
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+ mmap(NULL /* start anywhere */,
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+ buf.length,
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+ PROT_READ | PROT_WRITE /* required */,
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+ MAP_SHARED /* recommended */,
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+ fd, buf.m.offset);
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+
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+ if (MAP_FAILED == buffers[n_buffers].start)
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+ errno_exit("mmap");
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+ }
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+}
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+
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+static void init_device(int fd) {
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+ struct v4l2_capability cap;
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+ struct v4l2_cropcap cropcap;
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+ struct v4l2_crop crop;
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+ struct v4l2_format fmt;
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+ unsigned int min;
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+
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+ if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
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+ if (EINVAL == errno) {
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+ fprintf(stderr, "%s is no V4L2 device\\n",
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+ dev_name);
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+ exit(EXIT_FAILURE);
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+ } else {
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+ errno_exit("VIDIOC_QUERYCAP");
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+ }
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+ }
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+
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+ if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
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+ fprintf(stderr, "%s is no video capture device\\n",
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+ dev_name);
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+ exit(EXIT_FAILURE);
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+ }
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+
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+ switch (io) {
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+ case IO_METHOD_READ:
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+ if (!(cap.capabilities & V4L2_CAP_READWRITE)) {
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+ fprintf(stderr, "%s does not support read i/o\\n",
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+ dev_name);
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+ exit(EXIT_FAILURE);
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+ }
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+ break;
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+
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+ case IO_METHOD_MMAP:
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+ case IO_METHOD_USERPTR:
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+ if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
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+ fprintf(stderr, "%s does not support streaming i/o\\n",
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+ dev_name);
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+ exit(EXIT_FAILURE);
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+ }
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+ break;
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+ }
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+
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+
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+ /* Select video input, video standard and tune here. */
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+
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+
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+ CLEAR(cropcap);
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+
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+ cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+
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+ if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) {
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+ crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ crop.c = cropcap.defrect; /* reset to default */
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+
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+ if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) {
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+ switch (errno) {
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+ case EINVAL:
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+ /* Cropping not supported. */
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+ break;
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+ default:
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+ /* Errors ignored. */
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+ break;
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+ }
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+ }
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+ } else {
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+ /* Errors ignored. */
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+ }
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+
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+
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+ CLEAR(fmt);
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+
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+ fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ if (force_format_width > 0) {
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+ fmt.fmt.pix.width = force_format_width;
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+ fmt.fmt.pix.height = force_format_height;
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+ fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24;
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+ fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
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+ printf("Requesting a cooler format!\n");
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+
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+ if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
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+ errno_exit("VIDIOC_S_FMT");
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+
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+ /* Note VIDIOC_S_FMT may change width and height. */
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+ } else {
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+ /* Preserve original settings as set by v4l2-ctl for example */
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+ if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt))
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+ errno_exit("VIDIOC_G_FMT");
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+ }
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+
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+ /* Buggy driver paranoia. */
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+ min = fmt.fmt.pix.width * 2;
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+ if (fmt.fmt.pix.bytesperline < min)
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+ fmt.fmt.pix.bytesperline = min;
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+ min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
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+ if (fmt.fmt.pix.sizeimage < min)
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+ fmt.fmt.pix.sizeimage = min;
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+
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+ switch (io) {
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+ case IO_METHOD_READ:
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+ //init_read(fmt.fmt.pix.sizeimage);
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+ break;
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+
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+ case IO_METHOD_MMAP:
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+ init_mmap(fd);
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+ break;
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+
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+ case IO_METHOD_USERPTR:
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+ //init_userp(fmt.fmt.pix.sizeimage);
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+ break;
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+ }
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+}
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+
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+static void process_image(const void *p, int size) {
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+ GdkPixbuf *pixbuf;
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+ pixbuf = gdk_pixbuf_new_from_data(p, GDK_COLORSPACE_RGB, FALSE, 8, 640, 480, 2 * 640, NULL, NULL);
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+ gtk_image_set_from_pixbuf(preview_image, pixbuf);
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+}
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+
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+static int read_frame(int fd) {
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+ struct v4l2_buffer buf;
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+ unsigned int i;
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+
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+ switch (io) {
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+ case IO_METHOD_READ:
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+ if (-1 == read(fd, buffers[0].start, buffers[0].length)) {
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+ switch (errno) {
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+ case EAGAIN:
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+ return 0;
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+
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+ case EIO:
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+ /* Could ignore EIO, see spec. */
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+
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+ /* fall through */
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+
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+ default:
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+ errno_exit("read");
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+ }
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+ }
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+
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+ process_image(buffers[0].start, buffers[0].length);
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+ break;
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+
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+ case IO_METHOD_MMAP:
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+ CLEAR(buf);
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+
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+ buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ buf.memory = V4L2_MEMORY_MMAP;
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+
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+ if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
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+ switch (errno) {
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+ case EAGAIN:
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+ return 0;
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+
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+ case EIO:
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+ /* Could ignore EIO, see spec. */
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+
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+ /* fall through */
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+
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+ default:
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+ errno_exit("VIDIOC_DQBUF");
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+ }
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+ }
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+
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+ //assert(buf.index < n_buffers);
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+
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+ process_image(buffers[buf.index].start, buf.bytesused);
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+
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+ if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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+ errno_exit("VIDIOC_QBUF");
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+ break;
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+
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+ case IO_METHOD_USERPTR:
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+ CLEAR(buf);
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+
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+ buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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+ buf.memory = V4L2_MEMORY_USERPTR;
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+
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+ if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
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+ switch (errno) {
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+ case EAGAIN:
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+ return 0;
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+
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+ case EIO:
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+ /* Could ignore EIO, see spec. */
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+
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+ /* fall through */
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+
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+ default:
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+ errno_exit("VIDIOC_DQBUF");
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+ }
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+ }
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+
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+ for (i = 0; i < n_buffers; ++i)
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+ if (buf.m.userptr == (unsigned long) buffers[i].start
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+ && buf.length == buffers[i].length)
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+ break;
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+
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+ //assert(i < n_buffers);
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+
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+ process_image((void *) buf.m.userptr, buf.bytesused);
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+
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+ if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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+ errno_exit("VIDIOC_QBUF");
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+ break;
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+ }
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+
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+ return 1;
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+}
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+
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+static void get_frame(int fd) {
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+ for (;;) {
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+ fd_set fds;
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+ struct timeval tv;
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+ int r;
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+
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+ FD_ZERO(&fds);
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+ FD_SET(fd, &fds);
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+
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+ /* Timeout. */
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+ tv.tv_sec = 2;
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+ tv.tv_usec = 0;
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+
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+ r = select(fd + 1, &fds, NULL, NULL, &tv);
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+
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+ if (-1 == r) {
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+ if (EINTR == errno)
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+ continue;
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+ errno_exit("select");
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+ }
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+
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+ if (0 == r) {
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+ fprintf(stderr, "select timeout\\n");
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+ exit(EXIT_FAILURE);
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+ }
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+
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+ if (read_frame(fd))
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+ break;
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+ /* EAGAIN - continue select loop. */
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+ }
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+}
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+
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+int main(int argc,
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+ char *argv[]) {
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+ GtkBuilder *builder;
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+ GObject *window;
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+ GObject *preview_box;
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+ GError *error = NULL;
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+
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+ gtk_init(&argc, &argv);
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+
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+ /* Construct a GtkBuilder instance and load our UI description */
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+ builder = gtk_builder_new();
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+ if (gtk_builder_add_from_file(builder, "camera.glade", &error) == 0) {
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+ g_printerr("Error loading file: %s\n", error->message);
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+ g_clear_error(&error);
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+ return 1;
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+ }
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+
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+ /* Connect signal handlers to the constructed widgets. */
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+ window = gtk_builder_get_object(builder, "window");
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+ preview_box = gtk_builder_get_object(builder, "preview_box");
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+ preview_image = gtk_builder_get_object(builder, "preview");
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+ g_signal_connect (window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
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+
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+ /* Load the css */
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+ GtkCssProvider *provider = gtk_css_provider_new();
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+ gtk_css_provider_load_from_path(provider, "camera.css", NULL);
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+ GtkStyleContext *context;
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+ context = gtk_widget_get_style_context(preview_box);
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+ gtk_style_context_add_provider(context, GTK_STYLE_PROVIDER(provider), GTK_STYLE_PROVIDER_PRIORITY_USER);
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+
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+ /* Grab a frame from the camera */
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+ int fd;
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+ fd = open("/dev/video0", O_RDWR);
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+ if (fd == -1) {
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|
+ g_printerr("Error opening video device: /dev/video0\n");
|
|
|
+ return 1;
|
|
|
+ }
|
|
|
+ init_device(fd);
|
|
|
+ start_capturing(fd);
|
|
|
+ get_frame(fd);
|
|
|
+
|
|
|
+ /* Show application */
|
|
|
+ gtk_widget_show(window);
|
|
|
+ gtk_main();
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
Martijn Braam
5 years ago