gdouble norm_center_x; /* coordinates of viewport center in the image, in range 0.0 - 1.0 */
gdouble norm_center_y; /* these coordinates are used for PR_SCROLL_RESET_NOCHANGE and should be preserved over periods with NULL pixbuf */
gdouble norm_center_x; /* coordinates of viewport center in the image, in range 0.0 - 1.0 */
gdouble norm_center_y; /* these coordinates are used for PR_SCROLL_RESET_NOCHANGE and should be preserved over periods with NULL pixbuf */