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   1 /*
   2  *  lgl-barcode-render-to-cairo.c
   3  *  Copyright (C) 2010  Jim Evins <evins@snaught.com>.
   4  *
   5  *  This file is part of libglbarcode.
   6  *
   7  *  libglbarcode is free software: you can redistribute it and/or modify
   8  *  it under the terms of the GNU Lesser General Public License as published by
   9  *  the Free Software Foundation, either version 3 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  libglbarcode is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU Lesser General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Lesser General Public License
  18  *  along with libglbarcode.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22
  23 #include "lgl-barcode-render-to-cairo.h"
  24
  25 #include <pango/pangocairo.h>
  26 #include <math.h>
  27
  28
  29 /*===========================================*/
  30 /* Private macros and constants.             */
  31 /*===========================================*/
  32
  33 #define FONT_SCALE (72.0/96.0)
  34 #define BARCODE_FONT_FAMILY      "Sans"
  35 #define BARCODE_FONT_WEIGHT      PANGO_WEIGHT_NORMAL
  36
  37
  38 /*===========================================*/
  39 /* Private types                             */
  40 /*===========================================*/
  41
  42
  43 /*===========================================*/
  44 /* Private globals                           */
  45 /*===========================================*/
  46
  47
  48 /*===========================================*/
  49 /* Local function prototypes                 */
  50 /*===========================================*/
  51
  52
  53 /****************************************************************************/
  54 /**
  55  * lgl_barcode_render_to_cairo:
  56  * @bc:     An #lglBarcode structure
  57  * @cr:     A #cairo_t context
  58  *
  59  * Render barcode to cairo context.  Context should be prepared with desired
  60  * translation and appropriate scale.  Context should be translated such that
  61  * the origin is at the desired location of the upper left hand corner of the
  62  * barcode bounding box.  Context should be scaled such that all dimensions
  63  * are in points ( 1 point = 1/72 inch ) and that positive y coordinates
  64  * go down the surface.
  65  */
  66 void
  67 lgl_barcode_render_to_cairo (const lglBarcode  *bc,
  68                              cairo_t           *cr)
  69 {
  70         GList                  *p;
  71
  72         lglBarcodeShape        *shape;
  73         lglBarcodeShapeLine    *line;
  74         lglBarcodeShapeBox     *box;
  75         lglBarcodeShapeChar    *bchar;
  76         lglBarcodeShapeString  *bstring;
  77         lglBarcodeShapeRing    *ring;
  78         lglBarcodeShapeHexagon *hexagon;
  79
  80         PangoLayout            *layout;
  81         PangoFontDescription   *desc;
  82         gchar                  *cstring;
  83         gdouble                 x_offset, y_offset;
  84         gint                    iw, ih;
  85         gdouble                 layout_width;
  86
  87
  88         for (p = bc->shapes; p != NULL; p = p->next) {
  89
  90                 shape = (lglBarcodeShape *)p->data;
  91
  92                 switch (shape->type)
  93                 {
  94
  95                 case LGL_BARCODE_SHAPE_LINE:
  96                         line = (lglBarcodeShapeLine *) shape;
  97
  98                         cairo_move_to (cr, line->x, line->y);
  99                         cairo_line_to (cr, line->x, line->y + line->length);
 100                         cairo_set_line_width (cr, line->width);
 101                         cairo_stroke (cr);
 102
 103                         break;
 104
 105                 case LGL_BARCODE_SHAPE_BOX:
 106                         box = (lglBarcodeShapeBox *) shape;
 107
 108                         cairo_rectangle (cr, box->x, box->y, box->width, box->height);
 109                         cairo_fill (cr);
 110
 111                         break;
 112
 113                 case LGL_BARCODE_SHAPE_CHAR:
 114                         bchar = (lglBarcodeShapeChar *) shape;
 115
 116                         layout = pango_cairo_create_layout (cr);
 117
 118                         desc = pango_font_description_new ();
 119                         pango_font_description_set_family (desc, BARCODE_FONT_FAMILY);
 120                         pango_font_description_set_size   (desc, bchar->fsize * PANGO_SCALE * FONT_SCALE);
 121                         pango_layout_set_font_description (layout, desc);
 122                         pango_font_description_free       (desc);
 123
 124                         cstring = g_strdup_printf ("%c", bchar->c);
 125                         pango_layout_set_text (layout, cstring, -1);
 126                         g_free (cstring);
 127
 128                         y_offset = 0.2 * bchar->fsize;
 129
 130                         cairo_move_to (cr, bchar->x, bchar->y-y_offset);
 131                         pango_cairo_show_layout (cr, layout);
 132
 133                         g_object_unref (layout);
 134
 135                         break;
 136
 137                 case LGL_BARCODE_SHAPE_STRING:
 138                         bstring = (lglBarcodeShapeString *) shape;
 139
 140                         layout = pango_cairo_create_layout (cr);
 141
 142                         desc = pango_font_description_new ();
 143                         pango_font_description_set_family (desc, BARCODE_FONT_FAMILY);
 144                         pango_font_description_set_size   (desc, bstring->fsize * PANGO_SCALE * FONT_SCALE);
 145                         pango_layout_set_font_description (layout, desc);
 146                         pango_font_description_free       (desc);
 147
 148                         pango_layout_set_text (layout, bstring->string, -1);
 149
 150                         pango_layout_get_size (layout, &iw, &ih);
 151                         layout_width = (gdouble)iw / (gdouble)PANGO_SCALE;
 152
 153                         x_offset = layout_width / 2.0;
 154                         y_offset = 0.2 * bstring->fsize;
 155
 156                         cairo_move_to (cr, (bstring->x - x_offset), (bstring->y - y_offset));
 157                         pango_cairo_show_layout (cr, layout);
 158
 159                         g_object_unref (layout);
 160
 161                         break;
 162
 163                 case LGL_BARCODE_SHAPE_RING:
 164                         ring = (lglBarcodeShapeRing *) shape;
 165
 166                         cairo_arc (cr, ring->x, ring->y, ring->radius, 0.0, 2 * G_PI);
 167                         cairo_set_line_width (cr, ring->line_width);
 168                         cairo_stroke (cr);
 169
 170                         break;
 171
 172                 case LGL_BARCODE_SHAPE_HEXAGON:
 173                         hexagon = (lglBarcodeShapeHexagon *) shape;
 174
 175                         cairo_move_to (cr, hexagon->x, hexagon->y);
 176                         cairo_line_to (cr, hexagon->x + 0.433*hexagon->height, hexagon->y + 0.25*hexagon->height);
 177                         cairo_line_to (cr, hexagon->x + 0.433*hexagon->height, hexagon->y + 0.75*hexagon->height);
 178                         cairo_line_to (cr, hexagon->x,                         hexagon->y +      hexagon->height);
 179                         cairo_line_to (cr, hexagon->x - 0.433*hexagon->height, hexagon->y + 0.75*hexagon->height);
 180                         cairo_line_to (cr, hexagon->x - 0.433*hexagon->height, hexagon->y + 0.25*hexagon->height);
 181                         cairo_close_path (cr);
 182                         cairo_fill (cr);
 183
 184                         break;
 185
 186                 default:
 187                         g_assert_not_reached ();
 188                         break;
 189
 190                 }
 191
 192         }
 193
 194 }
 195
 196
 197 /****************************************************************************/
 198 /**
 199  * lgl_barcode_render_to_cairo_path:
 200  * @bc:     An #lglBarcode structure
 201  * @cr:     A #cairo_t context
 202  *
 203  * Render barcode to cairo context, but only create a path to be filled or
 204  * tested against.  Context should be prepared with desired
 205  * translation and appropriate scale.  Context should be translated such that
 206  * the origin is at the desired location of the upper left hand corner of the
 207  * barcode bounding box.  Context should be scaled such that all dimensions
 208  * are in points ( 1 point = 1/72 inch ) and that positive y coordinates
 209  * go down the surface.
 210  */
 211 void
 212 lgl_barcode_render_to_cairo_path (const lglBarcode  *bc,
 213                                   cairo_t           *cr)
 214 {
 215         GList                  *p;
 216
 217         lglBarcodeShape        *shape;
 218         lglBarcodeShapeLine    *line;
 219         lglBarcodeShapeBox     *box;
 220         lglBarcodeShapeChar    *bchar;
 221         lglBarcodeShapeString  *bstring;
 222         lglBarcodeShapeRing    *ring;
 223         lglBarcodeShapeHexagon *hexagon;
 224
 225         PangoLayout            *layout;
 226         PangoFontDescription   *desc;
 227         gchar                  *cstring;
 228         gdouble                 x_offset, y_offset;
 229         gint                    iw, ih;
 230         gdouble                 layout_width;
 231
 232
 233         for (p = bc->shapes; p != NULL; p = p->next) {
 234
 235                 shape = (lglBarcodeShape *)p->data;
 236
 237                 switch (shape->type)
 238                 {
 239
 240                 case LGL_BARCODE_SHAPE_LINE:
 241                         line = (lglBarcodeShapeLine *) shape;
 242
 243                         cairo_rectangle (cr, line->x - line->width/2, line->y, line->width, line->length);
 244
 245                         break;
 246
 247                 case LGL_BARCODE_SHAPE_BOX:
 248                         box = (lglBarcodeShapeBox *) shape;
 249
 250                         cairo_rectangle (cr, box->x, box->y, box->width, box->height);
 251
 252                         break;
 253
 254                 case LGL_BARCODE_SHAPE_CHAR:
 255                         bchar = (lglBarcodeShapeChar *) shape;
 256
 257                         layout = pango_cairo_create_layout (cr);
 258
 259                         desc = pango_font_description_new ();
 260                         pango_font_description_set_family (desc, BARCODE_FONT_FAMILY);
 261                         pango_font_description_set_size   (desc, bchar->fsize * PANGO_SCALE * FONT_SCALE);
 262                         pango_layout_set_font_description (layout, desc);
 263                         pango_font_description_free       (desc);
 264
 265                         cstring = g_strdup_printf ("%c", bchar->c);
 266                         pango_layout_set_text (layout, cstring, -1);
 267                         g_free (cstring);
 268
 269                         y_offset = 0.2 * bchar->fsize;
 270
 271                         cairo_move_to (cr, bchar->x, bchar->y-y_offset);
 272                         pango_cairo_layout_path (cr, layout);
 273
 274                         g_object_unref (layout);
 275
 276                         break;
 277
 278                 case LGL_BARCODE_SHAPE_STRING:
 279                         bstring = (lglBarcodeShapeString *) shape;
 280
 281                         layout = pango_cairo_create_layout (cr);
 282
 283                         desc = pango_font_description_new ();
 284                         pango_font_description_set_family (desc, BARCODE_FONT_FAMILY);
 285                         pango_font_description_set_size   (desc, bstring->fsize * PANGO_SCALE * FONT_SCALE);
 286                         pango_layout_set_font_description (layout, desc);
 287                         pango_font_description_free       (desc);
 288
 289                         pango_layout_set_text (layout, bstring->string, -1);
 290
 291                         pango_layout_get_size (layout, &iw, &ih);
 292                         layout_width = (gdouble)iw / (gdouble)PANGO_SCALE;
 293
 294                         x_offset = layout_width / 2.0;
 295                         y_offset = 0.2 * bstring->fsize;
 296
 297                         cairo_move_to (cr, (bstring->x - x_offset), (bstring->y - y_offset));
 298                         pango_cairo_layout_path (cr, layout);
 299
 300                         g_object_unref (layout);
 301
 302                         break;
 303
 304                 case LGL_BARCODE_SHAPE_RING:
 305                         ring = (lglBarcodeShapeRing *) shape;
 306
 307                         cairo_new_sub_path (cr);
 308                         cairo_arc (cr, ring->x, ring->y, ring->radius + ring->line_width/2, 0.0, 2 * G_PI);
 309                         cairo_close_path (cr);
 310                         cairo_new_sub_path (cr);
 311                         cairo_arc (cr, ring->x, ring->y, ring->radius - ring->line_width/2, 0.0, 2 * G_PI);
 312                         cairo_close_path (cr);
 313                         break;
 314
 315                 case LGL_BARCODE_SHAPE_HEXAGON:
 316                         hexagon = (lglBarcodeShapeHexagon *) shape;
 317
 318                         cairo_move_to (cr, hexagon->x, hexagon->y);
 319                         cairo_line_to (cr, hexagon->x + 0.433*hexagon->height, hexagon->y + 0.25*hexagon->height);
 320                         cairo_line_to (cr, hexagon->x + 0.433*hexagon->height, hexagon->y + 0.75*hexagon->height);
 321                         cairo_line_to (cr, hexagon->x,                         hexagon->y +      hexagon->height);
 322                         cairo_line_to (cr, hexagon->x - 0.433*hexagon->height, hexagon->y + 0.75*hexagon->height);
 323                         cairo_line_to (cr, hexagon->x - 0.433*hexagon->height, hexagon->y + 0.25*hexagon->height);
 324                         cairo_close_path (cr);
 325                         break;
 326
 327                 default:
 328                         g_assert_not_reached ();
 329                         break;
 330
 331                 }
 332
 333         }
 334
 335 }
 336
 337
 338
 339 /*
 340  * Local Variables:       -- emacs
 341  * mode: C                -- emacs
 342  * c-basic-offset: 8      -- emacs
 343  * tab-width: 8           -- emacs
 344  * indent-tabs-mode: nil  -- emacs
 345  * End:                   -- emacs
 346  */