core/GP_Transform.h

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2010 Jiri "BlueBear" Dluhos                            *
  20  *                         <jiri.bluebear.dluhos@gmail.com>                  *
  21  *                                                                           *
  22  * Copyright (C) 2009-2010 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  * Copyright (C) 2011      Tomas Gavenciak <gavento@ucw.cz>                  *
  25  *                                                                           *
  26  *****************************************************************************/
  27
  28 #ifndef GP_TRANSFORM_H
  29 #define GP_TRANSFORM_H
  30
  31 /*
  32  * Flip a coordinate within context according to context transformation.
  33  */
  34 #define GP_TRANSFORM_X(context, x) do { \
  35         if ((context)->x_swap)          \
  36                 x = (context)->w - x - 1;   \
  37 } while (0)
  38
  39 #define GP_TRANSFORM_Y(context, y) do { \
  40         if ((context)->y_swap)          \
  41                 y = (context)->h - y - 1;   \
  42 } while (0)
  43
  44 /*
  45  * Swap coordinates (axes) according to context transformation.
  46  */
  47 #define GP_TRANSFORM_SWAP(context, x, y) do { \
  48         if ((context)->axes_swap)             \
  49                 GP_SWAP(x, y);                \
  50 } while (0)
  51
  52 /*
  53  * Transform "user"-coordinates to "real"-coordinates according to context
  54  * transformation.
  55  */
  56 #define GP_TRANSFORM_POINT(context, x, y) do { \
  57         GP_TRANSFORM_SWAP(context, x, y);      \
  58         GP_TRANSFORM_X(context, x);            \
  59         GP_TRANSFORM_Y(context, y);            \
  60 } while (0)
  61
  62 /*
  63  * Transform "user"-coordinates to "real"-coordinates of a rectangle corner
  64  * according to context transformation. Corner with min-coordinates is
  65  * transformed to (different) corner with min-coordinates etc.
  66  */
  67 #define GP_TRANSFORM_RECT(context, x, y, rw, rh) do { \
  68         GP_TRANSFORM_SWAP(context, x, y);             \
  69         GP_TRANSFORM_SWAP(context, w, h);             \
  70         if ((context)->x_swap) {                      \
  71                 x = (context)->w - x - rw;            \
  72         }                                             \
  73         if ((context)->y_swap) {                      \
  74                 y = (context)->h - y - rh;            \
  75         }                                             \
  76 } while (0)
  77
  78 /*
  79  * Inverse transformation to GP_TRANSFORM_POINT.
  80  * Use for translating mouse pointer coordinates to coordinates on context.
  81  */
  82 #define GP_RETRANSFORM_POINT(context, x, y) do { \
  83         GP_TRANSFORM_X(context, x);              \
  84         GP_TRANSFORM_Y(context, y);              \
  85         GP_TRANSFORM_SWAP(context, x, y);        \
  86 } while (0)
  87
  88 #endif /* GP_TRANSFORM_H */