cpml/cpml-extents.c

   1 /* CPML - Cairo Path Manipulation Library
   2  * Copyright (C) 2008, 2009  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-extents.h"
  44
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <math.h>
  48
  49
  50 /**
  51  * cpml_extents_copy:
  52  * @extents: the destination #CpmlExtents
  53  * @src: the source #CpmlExtents
  54  *
  55  * Copies @src in @extents.
  56  *
  57  * Return value: @extents
  58  **/
  59 CpmlExtents *
  60 cpml_extents_copy(CpmlExtents *extents, const CpmlExtents *src)
  61 {
  62     return memcpy(extents, src, sizeof(CpmlExtents));
  63 }
  64
  65 /**
  66  * cpml_extents_from_cairo_text:
  67  * @extents: the destination #CpmlExtents
  68  * @cairo_extents: the source cairo_text_extents_t struct
  69  *
  70  * Converts @cairo_extents in a #CpmlExtents format and stores the
  71  * result in @extents.
  72  *
  73  * Returns: @extents
  74  **/
  75 CpmlExtents *
  76 cpml_extents_from_cairo_text(CpmlExtents *extents,
  77                              const cairo_text_extents_t *cairo_extents)
  78 {
  79     extents->is_defined = 1;
  80     extents->org.x = cairo_extents->x_bearing;
  81     extents->org.y = cairo_extents->y_bearing;
  82     extents->size.x = cairo_extents->width;
  83     extents->size.y = cairo_extents->height;
  84
  85     return extents;
  86 }
  87
  88 /**
  89  * cpml_extents_add:
  90  * @extents: the destination #CpmlExtents
  91  * @src: the extents to add
  92  *
  93  * Merges @extents and @src and store the result in @extents.
  94  **/
  95 void
  96 cpml_extents_add(CpmlExtents *extents, const CpmlExtents *src)
  97 {
  98     CpmlPair pair;
  99
 100     if (src->is_defined == 0)
 101         return;
 102
 103     cpml_pair_copy(&pair, &src->org);
 104     cpml_extents_pair_add(extents, &pair);
 105
 106     cpml_pair_add(&pair, &src->size);
 107     cpml_extents_pair_add(extents, &pair);
 108 }
 109
 110 /**
 111  * cpml_extents_pair_add:
 112  * @extents: the destination #CpmlExtents
 113  * @src: the #AdgPair to add
 114  *
 115  * Extends @extents, if required, to include @src. If @extents is
 116  * undefined, the origin of @extents is set to @src and its size
 117  * will be (0,0).
 118  **/
 119 void
 120 cpml_extents_pair_add(CpmlExtents *extents, const CpmlPair *src)
 121 {
 122     if (extents->is_defined == 0) {
 123         extents->is_defined = 1;
 124         cpml_pair_copy(&extents->org, src);
 125         extents->size.x = 0;
 126         extents->size.y = 0;
 127         return;
 128     }
 129
 130     if (src->x < extents->org.x) {
 131         extents->size.x += extents->org.x - src->x;
 132         extents->org.x = src->x;
 133     } else if (src->x > extents->org.x + extents->size.x) {
 134         extents->size.x = src->x - extents->org.x;
 135     }
 136
 137     if (src->y < extents->org.y) {
 138         extents->size.y += extents->org.y - src->y;
 139         extents->org.y = src->y;
 140     } else if (src->y > extents->org.y + extents->size.y) {
 141         extents->size.y = src->y - extents->org.y;
 142     }
 143 }
 144
 145 /**
 146  * cpml_extents_is_inside:
 147  * @extents: the container #CpmlExtents
 148  * @src: the subject #CpmlExtents
 149  *
 150  * Checks wheter @src is enterely contained by @extents. If @extents
 151  * is undefined, %0 will be returned. If @src is undefined, %1 will
 152  * be returned. The border of @extents is considered inside.
 153  *
 154  * Returns: %1 if @src is totally inside @extents, %0 otherwise
 155  **/
 156 cairo_bool_t
 157 cpml_extents_is_inside(const CpmlExtents *extents, const CpmlExtents *src)
 158 {
 159     CpmlPair pe, ps;
 160
 161     if (extents->is_defined == 0)
 162         return 0;
 163
 164     if (src->is_defined == 0)
 165         return 1;
 166
 167     cpml_pair_copy(&pe, &extents->org);
 168     cpml_pair_copy(&ps, &src->org);
 169
 170     if (ps.x < pe.x || ps.y < pe.y)
 171         return 0;
 172
 173     cpml_pair_add(&pe, &extents->size);
 174     cpml_pair_add(&ps, &src->size);
 175
 176     if (ps.x > pe.x || ps.y > pe.y)
 177         return 0;
 178
 179     return 1;
 180 }
 181
 182 /**
 183  * cpml_extents_pair_is_inside:
 184  * @extents: the container #CpmlExtents
 185  * @src: the subject #CpmlPair
 186  *
 187  * Checks wheter @src is inside @extents. If @extents is undefined,
 188  * %0 will be returned. The border of @extents is considered inside.
 189  *
 190  * Returns: %1 if @src is inside @extents, %0 otherwise
 191  **/
 192 cairo_bool_t
 193 cpml_extents_pair_is_inside(const CpmlExtents *extents, const CpmlPair *src)
 194 {
 195     if (extents->is_defined == 0)
 196         return 0;
 197
 198     if (src->x < extents->org.x || src->y < extents->org.y ||
 199         src->x > extents->org.x + extents->size.x ||
 200         src->y > extents->org.y + extents->size.y)
 201         return 0;
 202
 203     return 1;
 204 }
 205
 206 /**
 207  * cpml_extents_transform:
 208  * @extents: the container #CpmlExtents
 209  * @matrix: the transformation matrix
 210  *
 211  * Shortcut to apply a specific transformation matrix to @extents.
 212  * It basically convert the <structfield>org</structfield> field
 213  * with cairo_matrix_transform_point() and <structfield>size</structfield>
 214  * with cairo_matrix_transform_distance().
 215  **/
 216 void
 217 cpml_extents_transform(CpmlExtents *extents, const cairo_matrix_t *matrix)
 218 {
 219     if (extents->is_defined == 0)
 220         return;
 221
 222     cairo_matrix_transform_point(matrix, &extents->org.x, &extents->org.y);
 223     cairo_matrix_transform_distance(matrix, &extents->size.x, &extents->size.y);
 224 }