+/*
+ * \brief
+ * Set alpha offset.
+ */
+static void setAlphaOff(struct rpi_state* state, int offset){
+ if (offset<0) offset*=-1;
+ offset%=1000;
+ sem_wait(&state->thd_par_sem);
+ state->alpha_offset=(unsigned short)offset;
+ sem_post(&state->thd_par_sem);
+}
+