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 Lesser 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  * 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 this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20 /**
  21  * SECTION:matrix
  22  * @title: AdgMatrix
  23  * @short_description: A wrapper for the cairo_matrix_t struct
  24  *
  25  * The AdgMatrix is essentially a wrapper for #cairo_matrix_t structures.
  26  */
  27
  28 #include "adg-matrix.h"
  29 #include <string.h>
  30
  31
  32 static AdgMatrix null_matrix = { 0., 0., 0., 0., 0., 0. };
  33 static AdgMatrix identity_matrix = { 1., 0., 0., 1., 0., 0. };
  34
  35
  36 GType
  37 adg_matrix_get_type(void)
  38 {
  39     static int matrix_type = 0;
  40
  41     if (G_UNLIKELY(matrix_type == 0))
  42         matrix_type = g_boxed_type_register_static("AdgMatrix",
  43                                                    (GBoxedCopyFunc) adg_matrix_dup,
  44                                                    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, const AdgMatrix * src)
 117 {
 118     g_return_val_if_fail(matrix != NULL, matrix);
 119     g_return_val_if_fail(src != NULL, matrix);
 120
 121     memcpy(matrix, src, sizeof(AdgMatrix));
 122
 123     return matrix;
 124 }
 125
 126 /**
 127  * adg_matrix_equal:
 128  * @matrix1: an #AdgMatrix
 129  * @matrix2: an #AdgMatrix
 130  *
 131  * Compares @matrix1 and @matrix2 and returns %TRUE if the matrices are equal.
 132  *
 133  * Return value: %TRUE if @matrix1 is equal to @matrix2, %FALSE otherwise
 134  */
 135 gboolean
 136 adg_matrix_equal(const AdgMatrix * matrix1, const AdgMatrix * matrix2)
 137 {
 138     g_return_val_if_fail(matrix1 != NULL, FALSE);
 139     g_return_val_if_fail(matrix2 != NULL, FALSE);
 140
 141     return memcmp(matrix1, matrix2, sizeof(AdgMatrix)) == 0;
 142 }