source/libs/cairo/cairo-src/src/cairo-font-options.c

   1 /* cairo - a vector graphics library with display and print output
   2  *
   3  * Copyright © 2005 Red Hat Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it either under the terms of the GNU Lesser General Public
   7  * License version 2.1 as published by the Free Software Foundation
   8  * (the "LGPL") or, at your option, under the terms of the Mozilla
   9  * Public License Version 1.1 (the "MPL"). If you do not alter this
  10  * notice, a recipient may use your version of this file under either
  11  * the MPL or the LGPL.
  12  *
  13  * You should have received a copy of the LGPL along with this library
  14  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  16  * You should have received a copy of the MPL along with this library
  17  * in the file COPYING-MPL-1.1
  18  *
  19  * The contents of this file are subject to the Mozilla Public License
  20  * Version 1.1 (the "License"); you may not use this file except in
  21  * compliance with the License. You may obtain a copy of the License at
  22  * http://www.mozilla.org/MPL/
  23  *
  24  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  25  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  26  * the specific language governing rights and limitations.
  27  *
  28  * The Original Code is the cairo graphics library.
  29  *
  30  * The Initial Developer of the Original Code is University of Southern
  31  * California.
  32  *
  33  * Contributor(s):
  34  *      Owen Taylor <otaylor@redhat.com>
  35  */
  36
  37 #include "cairoint.h"
  38 #include "cairo-error-private.h"
  39
  40 /**
  41  * SECTION:cairo-font-options
  42  * @Title: cairo_font_options_t
  43  * @Short_Description: How a font should be rendered
  44  * @See_Also: #cairo_scaled_font_t
  45  *
  46  * The font options specify how fonts should be rendered.  Most of the
  47  * time the font options implied by a surface are just right and do not
  48  * need any changes, but for pixel-based targets tweaking font options
  49  * may result in superior output on a particular display.
  50  **/
  51
  52 static const cairo_font_options_t _cairo_font_options_nil = {
  53     CAIRO_ANTIALIAS_DEFAULT,
  54     CAIRO_SUBPIXEL_ORDER_DEFAULT,
  55     CAIRO_LCD_FILTER_DEFAULT,
  56     CAIRO_HINT_STYLE_DEFAULT,
  57     CAIRO_HINT_METRICS_DEFAULT,
  58     CAIRO_ROUND_GLYPH_POS_DEFAULT
  59 };
  60
  61 /**
  62  * _cairo_font_options_init_default:
  63  * @options: a #cairo_font_options_t
  64  *
  65  * Initializes all fields of the font options object to default values.
  66  **/
  67 void
  68 _cairo_font_options_init_default (cairo_font_options_t *options)
  69 {
  70     options->antialias = CAIRO_ANTIALIAS_DEFAULT;
  71     options->subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT;
  72     options->lcd_filter = CAIRO_LCD_FILTER_DEFAULT;
  73     options->hint_style = CAIRO_HINT_STYLE_DEFAULT;
  74     options->hint_metrics = CAIRO_HINT_METRICS_DEFAULT;
  75     options->round_glyph_positions = CAIRO_ROUND_GLYPH_POS_DEFAULT;
  76 }
  77
  78 void
  79 _cairo_font_options_init_copy (cairo_font_options_t             *options,
  80                                const cairo_font_options_t       *other)
  81 {
  82     options->antialias = other->antialias;
  83     options->subpixel_order = other->subpixel_order;
  84     options->lcd_filter = other->lcd_filter;
  85     options->hint_style = other->hint_style;
  86     options->hint_metrics = other->hint_metrics;
  87     options->round_glyph_positions = other->round_glyph_positions;
  88 }
  89
  90 /**
  91  * cairo_font_options_create:
  92  *
  93  * Allocates a new font options object with all options initialized
  94  *  to default values.
  95  *
  96  * Return value: a newly allocated #cairo_font_options_t. Free with
  97  *   cairo_font_options_destroy(). This function always returns a
  98  *   valid pointer; if memory cannot be allocated, then a special
  99  *   error object is returned where all operations on the object do nothing.
 100  *   You can check for this with cairo_font_options_status().
 101  *
 102  * Since: 1.0
 103  **/
 104 cairo_font_options_t *
 105 cairo_font_options_create (void)
 106 {
 107     cairo_font_options_t *options;
 108
 109     options = malloc (sizeof (cairo_font_options_t));
 110     if (!options) {
 111         _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
 112         return (cairo_font_options_t *) &_cairo_font_options_nil;
 113     }
 114
 115     _cairo_font_options_init_default (options);
 116
 117     return options;
 118 }
 119
 120 /**
 121  * cairo_font_options_copy:
 122  * @original: a #cairo_font_options_t
 123  *
 124  * Allocates a new font options object copying the option values from
 125  *  @original.
 126  *
 127  * Return value: a newly allocated #cairo_font_options_t. Free with
 128  *   cairo_font_options_destroy(). This function always returns a
 129  *   valid pointer; if memory cannot be allocated, then a special
 130  *   error object is returned where all operations on the object do nothing.
 131  *   You can check for this with cairo_font_options_status().
 132  *
 133  * Since: 1.0
 134  **/
 135 cairo_font_options_t *
 136 cairo_font_options_copy (const cairo_font_options_t *original)
 137 {
 138     cairo_font_options_t *options;
 139
 140     if (cairo_font_options_status ((cairo_font_options_t *) original))
 141         return (cairo_font_options_t *) &_cairo_font_options_nil;
 142
 143     options = malloc (sizeof (cairo_font_options_t));
 144     if (!options) {
 145         _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
 146         return (cairo_font_options_t *) &_cairo_font_options_nil;
 147     }
 148
 149     _cairo_font_options_init_copy (options, original);
 150
 151     return options;
 152 }
 153
 154 /**
 155  * cairo_font_options_destroy:
 156  * @options: a #cairo_font_options_t
 157  *
 158  * Destroys a #cairo_font_options_t object created with
 159  * cairo_font_options_create() or cairo_font_options_copy().
 160  *
 161  * Since: 1.0
 162  **/
 163 void
 164 cairo_font_options_destroy (cairo_font_options_t *options)
 165 {
 166     if (cairo_font_options_status (options))
 167         return;
 168
 169     free (options);
 170 }
 171
 172 /**
 173  * cairo_font_options_status:
 174  * @options: a #cairo_font_options_t
 175  *
 176  * Checks whether an error has previously occurred for this
 177  * font options object
 178  *
 179  * Return value: %CAIRO_STATUS_SUCCESS or %CAIRO_STATUS_NO_MEMORY
 180  *
 181  * Since: 1.0
 182  **/
 183 cairo_status_t
 184 cairo_font_options_status (cairo_font_options_t *options)
 185 {
 186     if (options == NULL)
 187         return CAIRO_STATUS_NULL_POINTER;
 188     else if (options == (cairo_font_options_t *) &_cairo_font_options_nil)
 189         return CAIRO_STATUS_NO_MEMORY;
 190     else
 191         return CAIRO_STATUS_SUCCESS;
 192 }
 193 slim_hidden_def (cairo_font_options_status);
 194
 195 /**
 196  * cairo_font_options_merge:
 197  * @options: a #cairo_font_options_t
 198  * @other: another #cairo_font_options_t
 199  *
 200  * Merges non-default options from @other into @options, replacing
 201  * existing values. This operation can be thought of as somewhat
 202  * similar to compositing @other onto @options with the operation
 203  * of %CAIRO_OPERATOR_OVER.
 204  *
 205  * Since: 1.0
 206  **/
 207 void
 208 cairo_font_options_merge (cairo_font_options_t       *options,
 209                           const cairo_font_options_t *other)
 210 {
 211     if (cairo_font_options_status (options))
 212         return;
 213
 214     if (cairo_font_options_status ((cairo_font_options_t *) other))
 215         return;
 216
 217     if (other->antialias != CAIRO_ANTIALIAS_DEFAULT)
 218         options->antialias = other->antialias;
 219     if (other->subpixel_order != CAIRO_SUBPIXEL_ORDER_DEFAULT)
 220         options->subpixel_order = other->subpixel_order;
 221     if (other->lcd_filter != CAIRO_LCD_FILTER_DEFAULT)
 222         options->lcd_filter = other->lcd_filter;
 223     if (other->hint_style != CAIRO_HINT_STYLE_DEFAULT)
 224         options->hint_style = other->hint_style;
 225     if (other->hint_metrics != CAIRO_HINT_METRICS_DEFAULT)
 226         options->hint_metrics = other->hint_metrics;
 227     if (other->round_glyph_positions != CAIRO_ROUND_GLYPH_POS_DEFAULT)
 228         options->round_glyph_positions = other->round_glyph_positions;
 229 }
 230 slim_hidden_def (cairo_font_options_merge);
 231
 232 /**
 233  * cairo_font_options_equal:
 234  * @options: a #cairo_font_options_t
 235  * @other: another #cairo_font_options_t
 236  *
 237  * Compares two font options objects for equality.
 238  *
 239  * Return value: %TRUE if all fields of the two font options objects match.
 240  *      Note that this function will return %FALSE if either object is in
 241  *      error.
 242  *
 243  * Since: 1.0
 244  **/
 245 cairo_bool_t
 246 cairo_font_options_equal (const cairo_font_options_t *options,
 247                           const cairo_font_options_t *other)
 248 {
 249     if (cairo_font_options_status ((cairo_font_options_t *) options))
 250         return FALSE;
 251     if (cairo_font_options_status ((cairo_font_options_t *) other))
 252         return FALSE;
 253
 254     if (options == other)
 255         return TRUE;
 256
 257     return (options->antialias == other->antialias &&
 258             options->subpixel_order == other->subpixel_order &&
 259             options->lcd_filter == other->lcd_filter &&
 260             options->hint_style == other->hint_style &&
 261             options->hint_metrics == other->hint_metrics &&
 262             options->round_glyph_positions == other->round_glyph_positions);
 263 }
 264 slim_hidden_def (cairo_font_options_equal);
 265
 266 /**
 267  * cairo_font_options_hash:
 268  * @options: a #cairo_font_options_t
 269  *
 270  * Compute a hash for the font options object; this value will
 271  * be useful when storing an object containing a #cairo_font_options_t
 272  * in a hash table.
 273  *
 274  * Return value: the hash value for the font options object.
 275  *   The return value can be cast to a 32-bit type if a
 276  *   32-bit hash value is needed.
 277  *
 278  * Since: 1.0
 279  **/
 280 unsigned long
 281 cairo_font_options_hash (const cairo_font_options_t *options)
 282 {
 283     if (cairo_font_options_status ((cairo_font_options_t *) options))
 284         options = &_cairo_font_options_nil; /* force default values */
 285
 286     return ((options->antialias) |
 287             (options->subpixel_order << 4) |
 288             (options->lcd_filter << 8) |
 289             (options->hint_style << 12) |
 290             (options->hint_metrics << 16));
 291 }
 292 slim_hidden_def (cairo_font_options_hash);
 293
 294 /**
 295  * cairo_font_options_set_antialias:
 296  * @options: a #cairo_font_options_t
 297  * @antialias: the new antialiasing mode
 298  *
 299  * Sets the antialiasing mode for the font options object. This
 300  * specifies the type of antialiasing to do when rendering text.
 301  *
 302  * Since: 1.0
 303  **/
 304 void
 305 cairo_font_options_set_antialias (cairo_font_options_t *options,
 306                                   cairo_antialias_t     antialias)
 307 {
 308     if (cairo_font_options_status (options))
 309         return;
 310
 311     options->antialias = antialias;
 312 }
 313 slim_hidden_def (cairo_font_options_set_antialias);
 314
 315 /**
 316  * cairo_font_options_get_antialias:
 317  * @options: a #cairo_font_options_t
 318  *
 319  * Gets the antialiasing mode for the font options object.
 320  *
 321  * Return value: the antialiasing mode
 322  *
 323  * Since: 1.0
 324  **/
 325 cairo_antialias_t
 326 cairo_font_options_get_antialias (const cairo_font_options_t *options)
 327 {
 328     if (cairo_font_options_status ((cairo_font_options_t *) options))
 329         return CAIRO_ANTIALIAS_DEFAULT;
 330
 331     return options->antialias;
 332 }
 333
 334 /**
 335  * cairo_font_options_set_subpixel_order:
 336  * @options: a #cairo_font_options_t
 337  * @subpixel_order: the new subpixel order
 338  *
 339  * Sets the subpixel order for the font options object. The subpixel
 340  * order specifies the order of color elements within each pixel on
 341  * the display device when rendering with an antialiasing mode of
 342  * %CAIRO_ANTIALIAS_SUBPIXEL. See the documentation for
 343  * #cairo_subpixel_order_t for full details.
 344  *
 345  * Since: 1.0
 346  **/
 347 void
 348 cairo_font_options_set_subpixel_order (cairo_font_options_t   *options,
 349                                        cairo_subpixel_order_t  subpixel_order)
 350 {
 351     if (cairo_font_options_status (options))
 352         return;
 353
 354     options->subpixel_order = subpixel_order;
 355 }
 356 slim_hidden_def (cairo_font_options_set_subpixel_order);
 357
 358 /**
 359  * cairo_font_options_get_subpixel_order:
 360  * @options: a #cairo_font_options_t
 361  *
 362  * Gets the subpixel order for the font options object.
 363  * See the documentation for #cairo_subpixel_order_t for full details.
 364  *
 365  * Return value: the subpixel order for the font options object
 366  *
 367  * Since: 1.0
 368  **/
 369 cairo_subpixel_order_t
 370 cairo_font_options_get_subpixel_order (const cairo_font_options_t *options)
 371 {
 372     if (cairo_font_options_status ((cairo_font_options_t *) options))
 373         return CAIRO_SUBPIXEL_ORDER_DEFAULT;
 374
 375     return options->subpixel_order;
 376 }
 377
 378 /**
 379  * _cairo_font_options_set_lcd_filter:
 380  * @options: a #cairo_font_options_t
 381  * @lcd_filter: the new LCD filter
 382  *
 383  * Sets the LCD filter for the font options object. The LCD filter
 384  * specifies how pixels are filtered when rendered with an antialiasing
 385  * mode of %CAIRO_ANTIALIAS_SUBPIXEL. See the documentation for
 386  * #cairo_lcd_filter_t for full details.
 387  **/
 388 void
 389 _cairo_font_options_set_lcd_filter (cairo_font_options_t *options,
 390                                     cairo_lcd_filter_t    lcd_filter)
 391 {
 392     if (cairo_font_options_status (options))
 393         return;
 394
 395     options->lcd_filter = lcd_filter;
 396 }
 397
 398 /**
 399  * _cairo_font_options_get_lcd_filter:
 400  * @options: a #cairo_font_options_t
 401  *
 402  * Gets the LCD filter for the font options object.
 403  * See the documentation for #cairo_lcd_filter_t for full details.
 404  *
 405  * Return value: the LCD filter for the font options object
 406  **/
 407 cairo_lcd_filter_t
 408 _cairo_font_options_get_lcd_filter (const cairo_font_options_t *options)
 409 {
 410     if (cairo_font_options_status ((cairo_font_options_t *) options))
 411         return CAIRO_LCD_FILTER_DEFAULT;
 412
 413     return options->lcd_filter;
 414 }
 415
 416 /**
 417  * _cairo_font_options_set_round_glyph_positions:
 418  * @options: a #cairo_font_options_t
 419  * @round: the new rounding value
 420  *
 421  * Sets the rounding options for the font options object. If rounding is set, a
 422  * glyph's position will be rounded to integer values.
 423  **/
 424 void
 425 _cairo_font_options_set_round_glyph_positions (cairo_font_options_t *options,
 426                                                cairo_round_glyph_positions_t  round)
 427 {
 428     if (cairo_font_options_status (options))
 429         return;
 430
 431     options->round_glyph_positions = round;
 432 }
 433
 434 /**
 435  * _cairo_font_options_get_round_glyph_positions:
 436  * @options: a #cairo_font_options_t
 437  *
 438  * Gets the glyph position rounding option for the font options object.
 439  *
 440  * Return value: The round glyph posistions flag for the font options object.
 441  **/
 442 cairo_round_glyph_positions_t
 443 _cairo_font_options_get_round_glyph_positions (const cairo_font_options_t *options)
 444 {
 445     if (cairo_font_options_status ((cairo_font_options_t *) options))
 446         return CAIRO_ROUND_GLYPH_POS_DEFAULT;
 447
 448     return options->round_glyph_positions;
 449 }
 450
 451 /**
 452  * cairo_font_options_set_hint_style:
 453  * @options: a #cairo_font_options_t
 454  * @hint_style: the new hint style
 455  *
 456  * Sets the hint style for font outlines for the font options object.
 457  * This controls whether to fit font outlines to the pixel grid,
 458  * and if so, whether to optimize for fidelity or contrast.
 459  * See the documentation for #cairo_hint_style_t for full details.
 460  *
 461  * Since: 1.0
 462  **/
 463 void
 464 cairo_font_options_set_hint_style (cairo_font_options_t *options,
 465                                    cairo_hint_style_t    hint_style)
 466 {
 467     if (cairo_font_options_status (options))
 468         return;
 469
 470     options->hint_style = hint_style;
 471 }
 472 slim_hidden_def (cairo_font_options_set_hint_style);
 473
 474 /**
 475  * cairo_font_options_get_hint_style:
 476  * @options: a #cairo_font_options_t
 477  *
 478  * Gets the hint style for font outlines for the font options object.
 479  * See the documentation for #cairo_hint_style_t for full details.
 480  *
 481  * Return value: the hint style for the font options object
 482  *
 483  * Since: 1.0
 484  **/
 485 cairo_hint_style_t
 486 cairo_font_options_get_hint_style (const cairo_font_options_t *options)
 487 {
 488     if (cairo_font_options_status ((cairo_font_options_t *) options))
 489         return CAIRO_HINT_STYLE_DEFAULT;
 490
 491     return options->hint_style;
 492 }
 493
 494 /**
 495  * cairo_font_options_set_hint_metrics:
 496  * @options: a #cairo_font_options_t
 497  * @hint_metrics: the new metrics hinting mode
 498  *
 499  * Sets the metrics hinting mode for the font options object. This
 500  * controls whether metrics are quantized to integer values in
 501  * device units.
 502  * See the documentation for #cairo_hint_metrics_t for full details.
 503  *
 504  * Since: 1.0
 505  **/
 506 void
 507 cairo_font_options_set_hint_metrics (cairo_font_options_t *options,
 508                                      cairo_hint_metrics_t  hint_metrics)
 509 {
 510     if (cairo_font_options_status (options))
 511         return;
 512
 513     options->hint_metrics = hint_metrics;
 514 }
 515 slim_hidden_def (cairo_font_options_set_hint_metrics);
 516
 517 /**
 518  * cairo_font_options_get_hint_metrics:
 519  * @options: a #cairo_font_options_t
 520  *
 521  * Gets the metrics hinting mode for the font options object.
 522  * See the documentation for #cairo_hint_metrics_t for full details.
 523  *
 524  * Return value: the metrics hinting mode for the font options object
 525  *
 526  * Since: 1.0
 527  **/
 528 cairo_hint_metrics_t
 529 cairo_font_options_get_hint_metrics (const cairo_font_options_t *options)
 530 {
 531     if (cairo_font_options_status ((cairo_font_options_t *) options))
 532         return CAIRO_HINT_METRICS_DEFAULT;
 533
 534     return options->hint_metrics;
 535 }