/* gamma.c * * Copyright © 2001 Lutz Müller <lutz@users.sf.net> * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #include "config.h" #include "gamma.h" #include <math.h> #include <gphoto2-result.h> static int gp_gamma_correct_triple (unsigned char *table_red, unsigned char *table_green, unsigned char *table_blue, unsigned char *data, unsigned int size) { int x; for (x = 0; x < (size * 3); x += 3) { data[x + 0] = table_red [data[x + 0]]; data[x + 1] = table_green[data[x + 1]]; data[x + 2] = table_blue [data[x + 2]]; } return (GP_OK); } int gp_gamma_correct_single (unsigned char *table, unsigned char *data, unsigned int size) { return (gp_gamma_correct_triple (table, table, table, data, size)); } int gp_gamma_fill_table (unsigned char *table, double g) { int x; for (x = 0; x < 256; x++) table[x] = 255 * pow ((double) x/255., g); return (GP_OK); }