adg/adg-matrix.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007-2008, Nicola Fontana <ntd at entidi.it>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library 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  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA  02111-1307, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:matrix
  23  * @title: AdgMatrix
  24  * @short_description: A wrapper for the cairo_matrix_t struct
  25  *
  26  * The AdgMatrix is essentially a wrapper for #cairo_matrix_t structures.
  27  */
  28
  29 #include "adg-matrix.h"
  30
  31 #include <string.h>
  32
  33
  34 static AdgMatrix null_matrix = { 0., 0., 0., 0., 0., 0. };
  35 static AdgMatrix identity_matrix = { 1., 0., 0., 1., 0., 0. };
  36
  37
  38 GType
  39 adg_matrix_get_type (void)
  40 {
  41   static int matrix_type = 0;
  42
  43   if G_UNLIKELY (matrix_type == 0)
  44     matrix_type = g_boxed_type_register_static ("AdgMatrix", (GBoxedCopyFunc) adg_matrix_dup, g_free);
  45
  46   return matrix_type;
  47 }
  48
  49 /**
  50  * adg_matrix_dup:
  51  * @matrix: an #AdgMatrix structure
  52  *
  53  * Duplicates @matrix.
  54  *
  55  * Return value: the duplicate of @matrix: must be freed with g_free()
  56  *               when no longer needed.
  57  */
  58 AdgMatrix *
  59 adg_matrix_dup (const AdgMatrix *matrix)
  60 {
  61   g_return_val_if_fail (matrix != NULL, NULL);
  62
  63   return g_memdup (matrix, sizeof (AdgMatrix));
  64 }
  65
  66 /**
  67  * adg_matrix_get_fallback:
  68  *
  69  * Gets a fallback matrix. The fallback matrix is a statically allocated
  70  * identity matrix.
  71  *
  72  * Return value: the fallback matrix
  73  */
  74 const AdgMatrix *
  75 adg_matrix_get_fallback (void)
  76 {
  77   return &identity_matrix;
  78 }
  79
  80 /**
  81  * adg_matrix_init_null:
  82  * @matrix: the #AdgMatrix to nullify
  83  *
  84  * Nullifies a matrix, setting all its components to 0.
  85  */
  86 void
  87 adg_matrix_init_null (AdgMatrix *matrix)
  88 {
  89   memcpy (matrix, &null_matrix, sizeof (AdgMatrix));
  90 }
  91
  92 /**
  93  * adg_matrix_is_null:
  94  * @matrix: the #AdgMatrix to check
  95  *
  96  * Checks if a matrix is a nullified matrix.
  97  *
  98  * Return value: %TRUE if the matrix is a null matrix, %FALSE otherwise
  99  */
 100 gboolean
 101 adg_matrix_is_null (const AdgMatrix *matrix)
 102 {
 103   return memcmp (matrix, &null_matrix, sizeof (AdgMatrix)) == 0;
 104 }
 105
 106 /**
 107  * adg_matrix_set:
 108  * @matrix: the destination #AdgMatrix
 109  * @src: the source #AdgMatrix
 110  *
 111  * Copies @matrix to @dst.
 112  *
 113  * Return value: @matrix
 114  */
 115 AdgMatrix *
 116 adg_matrix_set (AdgMatrix       *matrix,
 117                 const AdgMatrix *src)
 118 {
 119   g_return_val_if_fail (matrix != NULL, matrix);
 120   g_return_val_if_fail (src != NULL, matrix);
 121
 122   memcpy (matrix, src, sizeof (AdgMatrix));
 123
 124   return matrix;
 125 }
 126
 127 /**
 128  * adg_matrix_equal:
 129  * @matrix1: an #AdgMatrix
 130  * @matrix2: an #AdgMatrix
 131  *
 132  * Compares @matrix1 and @matrix2 and returns %TRUE if the matrices are equal.
 133  *
 134  * Return value: %TRUE if @matrix1 is equal to @matrix2, %FALSE otherwise
 135  */
 136 gboolean
 137 adg_matrix_equal (const AdgMatrix *matrix1,
 138                   const AdgMatrix *matrix2)
 139 {
 140   g_return_val_if_fail (matrix1 != NULL, FALSE);
 141   g_return_val_if_fail (matrix2 != NULL, FALSE);
 142
 143   return memcmp (matrix1, matrix2, sizeof (AdgMatrix)) == 0;
 144 }