how to save a screenshot (or a frame) from a camera stream

yes|sudo apt-get install libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev
yes|sudo apt-get install libgtk2.0
#g++ -Wall `pkg-config gtk+-2.0 --cflags` `pkg-config gstreamer-0.10 --cflags` -c example.cpp -o example.o 
#OR directly
g++ -Wall -Wall \
-pthread \
-I/usr/include/gtk-2.0 \
-I/usr/lib/i386-linux-gnu/gtk-2.0/include \
-I/usr/include/atk-1.0 \
-I/usr/include/cairo \
-I/usr/include/gdk-pixbuf-2.0 \
-I/usr/include/pango-1.0 \
-I/usr/include/gio-unix-2.0/ \
-I/usr/include/glib-2.0 \
-I/usr/lib/i386-linux-gnu/glib-2.0/include \
-I/usr/include/pixman-1 \
-I/usr/include/freetype2 \
-I/usr/include/libpng12 \
-I/usr/include/glib-2.0 \
-I/usr/lib/i386-linux-gnu/glib-2.0/include \
-I/usr/include/gstreamer-0.10 \
-I/usr/include/libxml2 \
-I/usr/include/glib-2.0 \
-I/usr/lib/i386-linux-gnu/glib-2.0/include \
-I/usr/include/gstreamer-0.10 \
-I/usr/include/libxml2  \
-g     -c example.cpp -o example.o

 #g++ `pkg-config gtk+-2.0 --libs` `pkg-config gstreamer-0.10 --libs` -lgstinterfaces-0.10 example.o -o example 
#OR directly
g++ example.o -o example \
-pthread -lgstreamer-0.10 \
-lgdk_pixbuf-2.0 
#include <string.h> /* for memset () */
#include <gst/gst.h>

//the base of the code https://vcs.maemo.org/svn/maemoexamples/tags/maemo_4.1/maemo-examples/example_camera.c
#include <gtk/gtk.h>
#include <gst/gst.h>
//#include <gst/interfaces/xoverlay.h>
#include <gdk/gdkx.h>

#define SAVE_FOLDER_DEFAULT  	 "./"
#define PHOTO_NAME_DEFAULT	 "Picture"
#define PHOTO_NAME_SUFFIX_DEFAULT ".bmp"
#define EXTENSION "bmp"
/* Creates a jpeg file from the buffer's raw image data */

bool takePhoto=false;

static gboolean create_jpeg(unsigned char *data)
{
    printf(".");
    GdkPixbuf *pixbuf = NULL;
    GError *error = NULL;
    guint height, width, bpp;
    const gchar *directory;
    GString *filename;
    guint base_len, i;
    struct stat statbuf;

    width = 640;
    height = 480;
    bpp = 24;

    /* Define the save folder */
    directory = SAVE_FOLDER_DEFAULT;
    if(directory == NULL)
    {
        directory = g_get_tmp_dir();
    }


    /* Create an unique file name */
    filename = g_string_new(g_build_filename(directory, PHOTO_NAME_DEFAULT, NULL));
    base_len = filename->len;
    g_string_append(filename, PHOTO_NAME_SUFFIX_DEFAULT);
    for(i = 1; !stat(filename->str, &statbuf); ++i)
    {
        g_string_truncate(filename, base_len);
        g_string_append_printf(filename, "%d%s", i, PHOTO_NAME_SUFFIX_DEFAULT);
    }


    /* Create a pixbuf object from the data */
    pixbuf = gdk_pixbuf_new_from_data(data,
                                      GDK_COLORSPACE_RGB, /* RGB-colorspace */
                                      FALSE, /* No alpha-channel */
                                      bpp/3, /* Bits per RGB-component */
                                      width, height, /* Dimensions */
                                      3*width, /* Number of bytes between lines (ie stride) */
                                      NULL, NULL); /* Callbacks */

    /* Save the pixbuf content's in to a jpeg file and check for
    * errors */
    if(!gdk_pixbuf_save(pixbuf, filename->str, EXTENSION, &error, NULL))
    {
        g_warning("%s\n", error->message);
        g_error_free(error);
        gdk_pixbuf_unref(pixbuf);
        g_string_free(filename, TRUE);
        return FALSE;
    }

    /* Free allocated resources and return TRUE which means
    * that the operation was succesful */
    g_string_free(filename, TRUE);
    gdk_pixbuf_unref(pixbuf);
    return TRUE;
}

GstElement *pipeline;
static gboolean
cb_handoff2 (GstElement *src,
             GstBuffer  *buffer,
             GstPad     *pad,
             gpointer    user_data)
{
    static gboolean white = FALSE;
    static int cnt=0;
    char *ptr=0;
    printf("got photo %d from %s, user_data=%p, buffer size=%d dur=%d\n", cnt++, ptr=gst_pad_get_name(pad), user_data, (int)buffer->size, (int)buffer->duration);
    if(takePhoto) printf("and yes! taking a photo\n");
    g_free(ptr);
    ptr=0;

    if(takePhoto)
    {
        //gst_element_change_state (pipeline, GST_STATE_CHANGE_READY_TO_PAUSED);
        create_jpeg((unsigned char *) GST_BUFFER_DATA(buffer));
        //gst_element_change_state (pipeline, GST_STATE_CHANGE_PAUSED_TO_PLAYING);
    }
    takePhoto=0;
    return TRUE;
}

gint ButtonPressed(GtkWidget* widget, gpointer data)
{
    g_print("You pressed the button.\n");
    takePhoto=1;
    return FALSE;
}
gint main(gint argc , gchar *argv[])
{

    GtkWidget *window;
    gtk_init(&argc, &argv);
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    //make_window_black(window);
    gtk_widget_show_all(window);
    GMainLoop *loop;
    loop = g_main_loop_new (NULL, FALSE);
    GtkWidget *button=gtk_button_new_with_label("photo");

    gtk_container_add(GTK_CONTAINER(window), button);
    gtk_widget_show_all(button);

    //gtk_signal_connect(GTK_OBJECT(window), "delete_event", GTK_SIGNAL_FUNC(Delete), NULL);

    g_signal_connect(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(ButtonPressed), NULL);


    GstElement *src
    , *tee
    , *queue1
    , *queue2
    , *videosink1
    , *videosink2
    ;
    gst_init (&argc, &argv);
    pipeline = gst_pipeline_new ("pipeline");
    src = gst_element_factory_make ("v4l2src", "source");
    tee = gst_element_factory_make ("tee", "t");
    queue1 = gst_element_factory_make ("queue", "q1");
    queue2 = gst_element_factory_make ("queue", "q2");
    videosink1 = gst_element_factory_make ("xvimagesink", "videosink");
    videosink2 = gst_element_factory_make ("fakesink", "videosink2");

    GstElement *flt = gst_element_factory_make ("capsfilter", "flt");
    GstElement *conv = gst_element_factory_make ("ffmpegcolorspace", "conv");
    GstCaps *caps=gst_caps_new_simple ("video/x-raw-rgb",
                                       "width", G_TYPE_INT, 3,
                                       "height", G_TYPE_INT, 2,
                                       NULL);
    g_object_set (G_OBJECT (flt), "caps",caps, NULL);
    g_object_set(G_OBJECT(videosink2),"signal-handoffs", TRUE,NULL);
    g_signal_connect(videosink2, "handoff", G_CALLBACK (cb_handoff2), NULL);

    gst_bin_add_many(GST_BIN (pipeline), src, tee,  queue1, videosink1, NULL);
    gst_bin_add_many(GST_BIN (pipeline),            queue2, videosink2, NULL);
    //gst_bin_add_many(GST_BIN (pipeline), flt, conv, NULL);

    gst_element_link_many (src, tee, queue1, videosink1, NULL);
    gst_element_link_many (     tee, queue2, videosink2, NULL);

    gst_element_set_state (pipeline, GST_STATE_PLAYING);

    g_main_loop_run (loop);
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(GST_OBJECT (pipeline));
    return 0;
}

how to save a screenshot (or a frame) from a camera stream

how to save a screenshot (or a frame) from a camera stream

Re: how to save a screenshot (or a frame) from a camera stream

Re: how to save a screenshot (or a frame) from a camera stream

Re: how to save a screenshot (or a frame) from a camera stream