capture: Use cvQueryFrame

The splitted cvGrabFrame + cvRetrieveFrame doesnt work as documented
anyway. cvGrabFrame _should_ be fast, but does select(2) with a timeout
of 2 seconds on the v4l fd.

1 files changed, 7 insertions, 18 deletions

diff --git a/capture.c b/capture.c
index 0c95796..4b6404c 100644
--- a/capture.c
+++ b/capture.c
@@ -130,14 +130,15 @@ draw_cb(GtkWidget *widget, cairo_t *cr, gpointer userdata)
 	return FALSE;
 }
 
-static void
-capture(struct ct *ct)
+static gboolean
+capture(gpointer userdata)
 {
+	struct ct *ct = userdata;
 	IplImage *image;
 	guchar *row1, *row2, *p1, *p2;
 	int x, y;
 
-	image = cvRetrieveFrame(ct->capture, 0);
+	image = cvQueryFrame(ct->capture);
 	if (!image) {
 		fprintf(stderr, "ERROR: frame is null...\n");
 		exit(EXIT_FAILURE);
@@ -174,19 +175,7 @@ capture(struct ct *ct)
 		row1 += image->widthStep;
 		row2 += cairo_image_surface_get_stride(ct->surface);
 	}
-}
-
-static gboolean
-grab(gpointer userdata)
-{
-	struct ct *ct = userdata;
-
-	if (cvGrabFrame(ct->capture) == 0)
-		return TRUE;
-
-	capture(ct);
 	gtk_widget_queue_draw(ct->drawing_area);
-
 	return TRUE;
 }
 
@@ -212,12 +201,12 @@ main(int argc, char *argv[])
 	       cvGetCaptureProperty(ct.capture, CV_CAP_PROP_FRAME_WIDTH),
 	       cvGetCaptureProperty(ct.capture, CV_CAP_PROP_FRAME_HEIGHT));
 
-	while (cvGrabFrame(ct.capture) == 0);
-	capture(&ct);
 
 	ct.window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 	ct.drawing_area = gtk_drawing_area_new();
 
+	capture(&ct);
+
 	gtk_widget_set_size_request(ct.drawing_area,
 				    cairo_image_surface_get_width(ct.surface),
 				    cairo_image_surface_get_height(ct.surface));
@@ -240,7 +229,7 @@ main(int argc, char *argv[])
 	g_signal_connect(ct.drawing_area, "motion-notify-event",
 			 G_CALLBACK(motion_notify_event), &ct); 
 
-	g_idle_add(grab, &ct);
+	g_idle_add(capture, &ct);
 	gtk_widget_show_all(ct.window);
 	gtk_main();