src/svg/svg-affine.cpp

   1 #define __SP_SVG_AFFINE_C__
   2
   3 /*
   4  * SVG data parser
   5  *
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *   Raph Levien <raph@acm.org>
   9  *
  10  * Copyright (C) 1999-2002 Lauris Kaplinski
  11  * Copyright (C) 1999 Raph Levien
  12  *
  13  * Released under GNU GPL, read the file 'COPYING' for more information
  14  */
  15
  16 #ifdef HAVE_CONFIG_H
  17 # include "config.h"
  18 #endif
  19
  20 #include <glib/gstrfuncs.h>
  21 #include <libnr/nr-matrix-fns.h>
  22 #include <libnr/nr-matrix-ops.h>
  23 #include <libnr/nr-matrix-translate-ops.h>
  24 #include <libnr/nr-rotate-fns.h>
  25 #include <libnr/nr-rotate-matrix-ops.h>
  26 #include <libnr/nr-scale-matrix-ops.h>
  27 #include <libnr/nr-translate-matrix-ops.h>
  28 #include <libnr/nr-translate-rotate-ops.h>
  29 #include "svg.h"
  30
  31 #ifndef M_PI
  32 # define M_PI 3.14159265358979323846
  33 #endif
  34
  35 bool
  36 sp_svg_transform_read(gchar const *str, NR::Matrix *transform)
  37 {
  38         int idx;
  39         char keyword[32];
  40         double args[6];
  41         int n_args;
  42         size_t key_len;
  43
  44         if (str == NULL) return false;
  45
  46         NR::Matrix a(NR::identity());
  47
  48         idx = 0;
  49         while (str[idx]) {
  50                 /* skip initial whitespace */
  51                 while (g_ascii_isspace (str[idx])) idx++;
  52
  53                 /* parse keyword */
  54                 for (key_len = 0; key_len < sizeof (keyword); key_len++) {
  55                         char c;
  56
  57                         c = str[idx];
  58                         if (g_ascii_isalpha (c) || c == '-') {
  59                                 keyword[key_len] = str[idx++];
  60                         } else {
  61                                 break;
  62                         }
  63                 }
  64                 if (key_len >= sizeof (keyword)) return false;
  65                 keyword[key_len] = '\0';
  66
  67                 /* skip whitespace */
  68                 while (g_ascii_isspace (str[idx])) idx++;
  69
  70                 if (str[idx] != '(') return false;
  71                 idx++;
  72
  73                 for (n_args = 0; ; n_args++) {
  74                         char c;
  75                         char *end_ptr;
  76
  77                         /* skip whitespace */
  78                         while (g_ascii_isspace (str[idx])) idx++;
  79                         c = str[idx];
  80                         if (g_ascii_isdigit (c) || c == '+' || c == '-' || c == '.') {
  81                                 if (n_args == sizeof (args) / sizeof (args[0])) return false; /* Too many args */
  82                                 args[n_args] = g_ascii_strtod (str + idx, &end_ptr);
  83
  84                                 //printf("took %d chars from '%s' to make %f\n",
  85                                 //              end_ptr-(str+idx),
  86                                 //              str+idx,
  87                                 //              args[n_args]);
  88
  89                                 idx = end_ptr - (char *) str;
  90
  91                                 while (g_ascii_isspace (str[idx])) idx++;
  92
  93                                 /* skip optional comma */
  94                                 if (str[idx] == ',') idx++;
  95                         } else if (c == ')') {
  96                                 break;
  97                         } else {
  98                                 return false;
  99                         }
 100                 }
 101                 idx++;
 102
 103                 /* ok, have parsed keyword and args, now modify the transform */
 104                 if (!strcmp (keyword, "matrix")) {
 105                         if (n_args != 6) return false;
 106                         a = NR_MATRIX_D_FROM_DOUBLE(args) * a;
 107                 } else if (!strcmp (keyword, "translate")) {
 108                         if (n_args == 1) {
 109                                 args[1] = 0;
 110                         } else if (n_args != 2) {
 111                                 return false;
 112                         }
 113                         a = NR::translate(args[0], args[1]) * a;
 114                 } else if (!strcmp (keyword, "scale")) {
 115                         if (n_args == 1) {
 116                                 args[1] = args[0];
 117                         } else if (n_args != 2) {
 118                                 return false;
 119                         }
 120                         a = NR::scale(args[0], args[1]) * a;
 121                 } else if (!strcmp (keyword, "rotate")) {
 122                         if (n_args != 1 && n_args != 3) {
 123                                 return false;
 124                         }
 125                         NR::rotate const rot(rotate_degrees(args[0]));
 126                         if (n_args == 3) {
 127                                 a = ( NR::translate(-args[1], -args[2])
 128                                       * rot
 129                                       * NR::translate(args[1], args[2])
 130                                       * a );
 131                         } else {
 132                                 a = rot * a;
 133                         }
 134                 } else if (!strcmp (keyword, "skewX")) {
 135                         if (n_args != 1) return false;
 136                         a = ( NR::Matrix(1, 0,
 137                                          tan(args[0] * M_PI / 180.0), 1,
 138                                          0, 0)
 139                               * a );
 140                 } else if (!strcmp (keyword, "skewY")) {
 141                         if (n_args != 1) return false;
 142                         a = ( NR::Matrix(1, tan(args[0] * M_PI / 180.0),
 143                                          0, 1,
 144                                          0, 0)
 145                               * a );
 146                 } else {
 147                         return false; /* unknown keyword */
 148                 }
 149                 /* Skip trailing whitespace */
 150              while (g_ascii_isspace (str[idx])) idx++;
 151         }
 152
 153         *transform = a;
 154         return true;
 155 }
 156
 157 #define EQ(a,b) (fabs ((a) - (b)) < 1e-9)
 158
 159 unsigned
 160 sp_svg_transform_write(gchar str[], unsigned const size, NR::Matrix const &transform)
 161 {
 162         NRMatrix const t(transform);
 163         return sp_svg_transform_write(str, size, &t);
 164 }
 165
 166 unsigned
 167 sp_svg_transform_write(gchar str[], unsigned const size, NRMatrix const *transform)
 168 {
 169         double e;
 170
 171         if (!transform) {
 172                 *str = 0;
 173                 return 0;
 174         }
 175
 176         e = 0.000001 * NR_MATRIX_DF_EXPANSION (transform);
 177
 178         /* fixme: We could use t1 * t1 + t2 * t2 here instead */
 179         if (NR_DF_TEST_CLOSE (transform->c[1], 0.0, e) && NR_DF_TEST_CLOSE (transform->c[2], 0.0, e)) {
 180                 if (NR_DF_TEST_CLOSE (transform->c[4], 0.0, e) && NR_DF_TEST_CLOSE (transform->c[5], 0.0, e)) {
 181                         if (NR_DF_TEST_CLOSE (transform->c[0], 1.0, e) && NR_DF_TEST_CLOSE (transform->c[3], 1.0, e)) {
 182                                 /* We are more or less identity */
 183                                 *str = 0;
 184                                 return 0;
 185                         } else {
 186                                 /* We are more or less scale */
 187                                 gchar c[256];
 188                                 unsigned p = 0;
 189                                 strcpy (c + p, "scale(");
 190                                 p += 6;
 191                                 p += sp_svg_number_write_de (c + p, transform->c[0], 6, FALSE);
 192                                 c[p++] = ',';
 193                                 p += sp_svg_number_write_de (c + p, transform->c[3], 6, FALSE);
 194                                 c[p++] = ')';
 195                                 g_assert( p <= sizeof(c) );
 196                                 p = MIN (p, size - 1 );
 197                                 memcpy (str, c, p);
 198                                 str[p] = 0;
 199                                 return p;
 200                         }
 201                 } else {
 202                         if (NR_DF_TEST_CLOSE (transform->c[0], 1.0, e) && NR_DF_TEST_CLOSE (transform->c[3], 1.0, e)) {
 203                                 /* We are more or less translate */
 204                                 gchar c[256];
 205                                 unsigned p = 0;
 206                                 strcpy (c + p, "translate(");
 207                                 p += 10;
 208                                 p += sp_svg_number_write_de (c + p, transform->c[4], 6, FALSE);
 209                                 c[p++] = ',';
 210                                 p += sp_svg_number_write_de (c + p, transform->c[5], 6, FALSE);
 211                                 c[p++] = ')';
 212                                 g_assert( p <= sizeof(c) );
 213                                 p = MIN(p, size - 1);
 214                                 memcpy (str, c, p);
 215                                 str[p] = 0;
 216                                 return p;
 217                         } else {
 218                                 gchar c[256];
 219                                 unsigned p = 0;
 220                                 strcpy (c + p, "matrix(");
 221                                 p += 7;
 222                                 p += sp_svg_number_write_de (c + p, transform->c[0], 6, FALSE);
 223                                 c[p++] = ',';
 224                                 p += sp_svg_number_write_de (c + p, transform->c[1], 6, FALSE);
 225                                 c[p++] = ',';
 226                                 p += sp_svg_number_write_de (c + p, transform->c[2], 6, FALSE);
 227                                 c[p++] = ',';
 228                                 p += sp_svg_number_write_de (c + p, transform->c[3], 6, FALSE);
 229                                 c[p++] = ',';
 230                                 p += sp_svg_number_write_de (c + p, transform->c[4], 6, FALSE);
 231                                 c[p++] = ',';
 232                                 p += sp_svg_number_write_de (c + p, transform->c[5], 6, FALSE);
 233                                 c[p++] = ')';
 234                                 g_assert( p <= sizeof(c) );
 235                                 p = MIN(p, size - 1);
 236                                 memcpy (str, c, p);
 237                                 str[p] = 0;
 238                                 return p;
 239                         }
 240                 }
 241         } else {
 242                 gchar c[256];
 243                 unsigned p = 0;
 244                 strcpy (c + p, "matrix(");
 245                 p += 7;
 246                 p += sp_svg_number_write_de (c + p, transform->c[0], 6, FALSE);
 247                 c[p++] = ',';
 248                 p += sp_svg_number_write_de (c + p, transform->c[1], 6, FALSE);
 249                 c[p++] = ',';
 250                 p += sp_svg_number_write_de (c + p, transform->c[2], 6, FALSE);
 251                 c[p++] = ',';
 252                 p += sp_svg_number_write_de (c + p, transform->c[3], 6, FALSE);
 253                 c[p++] = ',';
 254                 p += sp_svg_number_write_de (c + p, transform->c[4], 6, FALSE);
 255                 c[p++] = ',';
 256                 p += sp_svg_number_write_de (c + p, transform->c[5], 6, FALSE);
 257                 c[p++] = ')';
 258                 g_assert( p <= sizeof(c) );
 259                 p = MIN(p, size - 1);
 260                 memcpy (str, c, p);
 261                 str[p] = 0;
 262                 return p;
 263         }
 264 }
 265