src/cpml/cpml-extents.c

   1 /* CPML - Cairo Path Manipulation Library
   2  * Copyright (C) 2008,2009,2010,2011  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 /**
  22  * SECTION:cpml-extents
  23  * @Section_Id:CpmlExtents
  24  * @title: CpmlExtents
  25  * @short_description: A rectangular area representing a bounding box
  26  *
  27  * The #CpmlExtents struct groups two pairs representing the rectangular
  28  * area of a bounding box.
  29  **/
  30
  31 /**
  32  * CpmlExtents:
  33  * @is_defined: set to %0 when these extents are undefined
  34  * @org: the lowest x,y coordinates
  35  * @size: the width (x) and height (y) of the extents
  36  *
  37  * A structure defining a bounding box area. These APIs expect the
  38  * size of the extents to be always positives, so be careful while
  39  * directly accessing the @size field.
  40  **/
  41
  42
  43 #include "cpml-internal.h"
  44 #include "cpml-extents.h"
  45 #include <string.h>
  46 #include <math.h>
  47
  48
  49 /**
  50  * cpml_extents_copy:
  51  * @extents: the destination #CpmlExtents
  52  * @src: the source #CpmlExtents
  53  *
  54  * Copies @src in @extents.
  55  *
  56  * Returns: @extents
  57  **/
  58 CpmlExtents *
  59 cpml_extents_copy(CpmlExtents *extents, const CpmlExtents *src)
  60 {
  61     return memcpy(extents, src, sizeof(CpmlExtents));
  62 }
  63
  64 /**
  65  * cpml_extents_from_cairo_text:
  66  * @extents: the destination #CpmlExtents
  67  * @cairo_extents: the source cairo_text_extents_t struct
  68  *
  69  * Converts @cairo_extents in a #CpmlExtents format and stores the
  70  * result in @extents.
  71  *
  72  * Returns: @extents
  73  **/
  74 CpmlExtents *
  75 cpml_extents_from_cairo_text(CpmlExtents *extents,
  76                              const cairo_text_extents_t *cairo_extents)
  77 {
  78     extents->is_defined = 1;
  79     extents->org.x = cairo_extents->x_bearing;
  80     extents->org.y = cairo_extents->y_bearing;
  81     extents->size.x = cairo_extents->width;
  82     extents->size.y = cairo_extents->height;
  83
  84     return extents;
  85 }
  86
  87 /**
  88  * cpml_extents_equal:
  89  * @extents: the first extents to compare
  90  * @src: the second extents to compare
  91  *
  92  * Compares @extents to @src and returns 1 if the extents are equals.
  93  * Two %NULL or two undefined extents are considered equal, athough
  94  * %NULL extents are not equal to undefined extents.
  95  *
  96  * Returns: 1 if @extents is equal to @src, 0 otherwise
  97  **/
  98 cairo_bool_t
  99 cpml_extents_equal(const CpmlExtents *extents, const CpmlExtents *src)
 100 {
 101     if (extents == NULL && src == NULL)
 102         return 1;
 103
 104     if (extents == NULL || src == NULL)
 105         return 0;
 106
 107     if (!extents->is_defined && !src->is_defined)
 108         return 1;
 109
 110     return extents->is_defined == src->is_defined &&
 111            cpml_pair_equal(&extents->org,  &src->org) &&
 112            cpml_pair_equal(&extents->size, &src->size) ? 1 : 0;
 113 }
 114
 115 /**
 116  * cpml_extents_add:
 117  * @extents: the destination #CpmlExtents
 118  * @src: the extents to add
 119  *
 120  * Merges @extents and @src and store the result in @extents.
 121  **/
 122 void
 123 cpml_extents_add(CpmlExtents *extents, const CpmlExtents *src)
 124 {
 125     CpmlPair pair;
 126
 127     if (src->is_defined == 0)
 128         return;
 129
 130     pair.x = src->org.x + src->size.x;
 131     pair.y = src->org.y + src->size.y;
 132
 133     cpml_extents_pair_add(extents, &src->org);
 134     cpml_extents_pair_add(extents, &pair);
 135 }
 136
 137 /**
 138  * cpml_extents_pair_add:
 139  * @extents: the destination #CpmlExtents
 140  * @src: the #AdgPair to add
 141  *
 142  * Extends @extents, if required, to include @src. If @extents is
 143  * undefined, the origin of @extents is set to @src and its size
 144  * will be (0,0).
 145  **/
 146 void
 147 cpml_extents_pair_add(CpmlExtents *extents, const CpmlPair *src)
 148 {
 149     if (extents->is_defined == 0) {
 150         extents->is_defined = 1;
 151         cpml_pair_copy(&extents->org, src);
 152         extents->size.x = 0;
 153         extents->size.y = 0;
 154         return;
 155     }
 156
 157     if (src->x < extents->org.x) {
 158         extents->size.x += extents->org.x - src->x;
 159         extents->org.x = src->x;
 160     } else if (src->x > extents->org.x + extents->size.x) {
 161         extents->size.x = src->x - extents->org.x;
 162     }
 163
 164     if (src->y < extents->org.y) {
 165         extents->size.y += extents->org.y - src->y;
 166         extents->org.y = src->y;
 167     } else if (src->y > extents->org.y + extents->size.y) {
 168         extents->size.y = src->y - extents->org.y;
 169     }
 170 }
 171
 172 /**
 173  * cpml_extents_is_inside:
 174  * @extents: the container #CpmlExtents
 175  * @src: the subject #CpmlExtents
 176  *
 177  * Checks wheter @src is enterely contained by @extents. If @extents
 178  * is undefined, %0 will be returned. If @src is undefined, %1 will
 179  * be returned. The border of @extents is considered inside.
 180  *
 181  * Returns: %1 if @src is totally inside @extents, %0 otherwise
 182  **/
 183 cairo_bool_t
 184 cpml_extents_is_inside(const CpmlExtents *extents, const CpmlExtents *src)
 185 {
 186     CpmlPair pe, ps;
 187
 188     if (extents->is_defined == 0)
 189         return 0;
 190
 191     if (src->is_defined == 0)
 192         return 1;
 193
 194     cpml_pair_copy(&pe, &extents->org);
 195     cpml_pair_copy(&ps, &src->org);
 196
 197     if (ps.x < pe.x || ps.y < pe.y)
 198         return 0;
 199
 200     pe.x += extents->size.x;
 201     pe.y += extents->size.y;
 202     ps.x += extents->size.x;
 203     ps.y += extents->size.y;
 204
 205     if (ps.x > pe.x || ps.y > pe.y)
 206         return 0;
 207
 208     return 1;
 209 }
 210
 211 /**
 212  * cpml_extents_pair_is_inside:
 213  * @extents: the container #CpmlExtents
 214  * @src: the subject #CpmlPair
 215  *
 216  * Checks wheter @src is inside @extents. If @extents is undefined,
 217  * %0 will be returned. The border of @extents is considered inside.
 218  *
 219  * Returns: %1 if @src is inside @extents, %0 otherwise
 220  **/
 221 cairo_bool_t
 222 cpml_extents_pair_is_inside(const CpmlExtents *extents, const CpmlPair *src)
 223 {
 224     if (extents->is_defined == 0)
 225         return 0;
 226
 227     if (src->x < extents->org.x || src->y < extents->org.y ||
 228         src->x > extents->org.x + extents->size.x ||
 229         src->y > extents->org.y + extents->size.y)
 230         return 0;
 231
 232     return 1;
 233 }
 234
 235 /**
 236  * cpml_extents_transform:
 237  * @extents: the container #CpmlExtents
 238  * @matrix: the transformation matrix
 239  *
 240  * Shortcut to apply a specific transformation matrix to @extents.
 241  * It basically convert the <structfield>org</structfield> field
 242  * with cairo_matrix_transform_point() and <structfield>size</structfield>
 243  * with cairo_matrix_transform_distance().
 244  **/
 245 void
 246 cpml_extents_transform(CpmlExtents *extents, const cairo_matrix_t *matrix)
 247 {
 248     if (extents->is_defined == 0)
 249         return;
 250
 251     cairo_matrix_transform_point(matrix, &extents->org.x, &extents->org.y);
 252     cairo_matrix_transform_distance(matrix, &extents->size.x, &extents->size.y);
 253 }