lib/diatransform.c

   1 /* Dia -- an diagram creation/manipulation program
   2  * Copyright (C) 1998 Alexander Larsson
   3  *
   4  * diatransform.c - scaling indirection to connect display
   5  *                  and renderers
   6  * Copyright (C) 2002 Hans Breuer (refactoring)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "diatransform.h"
  24
  25 typedef struct _DiaTransformClass DiaTransformClass;
  26
  27 struct _DiaTransform
  28 {
  29   GObject parent_instance;
  30   /*< private >*/
  31   Rectangle *visible; /* pointer to original rectangle for transform_coords */
  32   real      *factor;  /* pointer to original factor for transform_length */
  33 };
  34
  35 struct _DiaTransformClass
  36 {
  37   GObjectClass parent_class;
  38 };
  39
  40 static void dia_transform_class_init (DiaTransformClass *klass);
  41
  42 static gpointer parent_class = NULL;
  43
  44 GType
  45 dia_transform_get_type (void)
  46 {
  47   static GType object_type = 0;
  48
  49   if (!object_type)
  50     {
  51       static const GTypeInfo object_info =
  52       {
  53         sizeof (DiaTransformClass),
  54         (GBaseInitFunc) NULL,
  55         (GBaseFinalizeFunc) NULL,
  56         (GClassInitFunc) dia_transform_class_init,
  57         NULL,           /* class_finalize */
  58         NULL,           /* class_data */
  59         sizeof (DiaTransform),
  60         0,              /* n_preallocs */
  61         NULL            /* init */
  62       };
  63
  64       object_type = g_type_register_static (G_TYPE_OBJECT,
  65                                             "DiaTransform",
  66                                             &object_info, 0);
  67     }
  68
  69   return object_type;
  70 }
  71
  72 static void
  73 dia_transform_finalize (GObject *object)
  74 {
  75   /* don't free the fields, we don't own them */
  76
  77   G_OBJECT_CLASS (parent_class)->finalize (object);
  78 }
  79
  80 static void
  81 dia_transform_class_init (DiaTransformClass *klass)
  82 {
  83   GObjectClass *object_class = G_OBJECT_CLASS (klass);
  84
  85   parent_class = g_type_class_peek_parent (klass);
  86
  87   object_class->finalize = dia_transform_finalize;
  88
  89 }
  90
  91 DiaTransform *
  92 dia_transform_new (Rectangle *rect, real* zoom)
  93 {
  94   DiaTransform *t = g_object_new (DIA_TYPE_TRANSFORM, NULL);
  95   t->visible = rect;
  96   t->factor = zoom;
  97
  98   return t;
  99 }
 100
 101 real
 102 dia_transform_length (DiaTransform *t, real len)
 103 {
 104   g_return_val_if_fail (DIA_IS_TRANSFORM (t), len);
 105   g_return_val_if_fail (t != NULL && *t->factor != 0.0, len);
 106
 107   return (len * *(t->factor));
 108 }
 109
 110 /* Takes pixel length and returns real length */
 111 real
 112 dia_untransform_length(DiaTransform *t, real len)
 113 {
 114   g_return_val_if_fail (DIA_IS_TRANSFORM (t), len);
 115   g_return_val_if_fail (t != NULL && *t->factor != 0.0, len);
 116
 117   return len / *(t->factor);
 118 }
 119
 120 void
 121 dia_transform_coords (DiaTransform *t,
 122                       coord x, coord y,
 123                       int *xi, int *yi)
 124 {
 125   g_return_if_fail (DIA_IS_TRANSFORM (t));
 126   g_return_if_fail (t != NULL && t->factor != NULL);
 127
 128   *xi = ROUND ( (x - t->visible->left) * *(t->factor));
 129   *yi = ROUND ( (y - t->visible->top) * *(t->factor));
 130 }
 131
 132 void
 133 dia_transform_coords_double (DiaTransform *t,
 134                              coord x, coord y,
 135                              double *xd, double *yd)
 136 {
 137   g_return_if_fail (DIA_IS_TRANSFORM (t));
 138   g_return_if_fail (t != NULL && t->factor != NULL);
 139
 140   *xd = ((x - t->visible->left) * *(t->factor));
 141   *yd = ((y - t->visible->top) * *(t->factor));
 142 }
 143