1 /***************************************************************************/ 2 /* */ 3 /* ftimage.h */ 4 /* */ 5 /* FreeType glyph image formats and default raster interface */ 6 /* (specification). */ 7 /* */ 8 /* Copyright 1996-2015 by */ 9 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 10 /* */ 11 /* This file is part of the FreeType project, and may only be used, */ 12 /* modified, and distributed under the terms of the FreeType project */ 13 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 14 /* this file you indicate that you have read the license and */ 15 /* understand and accept it fully. */ 16 /* */ 17 /***************************************************************************/ 18 19 /*************************************************************************/ 20 /* */ 21 /* Note: A `raster' is simply a scan-line converter, used to render */ 22 /* FT_Outlines into FT_Bitmaps. */ 23 /* */ 24 /*************************************************************************/ 25 26 27 #ifndef __FTIMAGE_H__ 28 #define __FTIMAGE_H__ 29 30 31 /* _STANDALONE_ is from ftgrays.c */ 32 #ifndef _STANDALONE_ 33 #include <ft2build.h> 34 #endif 35 36 37 FT_BEGIN_HEADER 38 39 40 /*************************************************************************/ 41 /* */ 42 /* <Section> */ 43 /* basic_types */ 44 /* */ 45 /*************************************************************************/ 46 47 48 /*************************************************************************/ 49 /* */ 50 /* <Type> */ 51 /* FT_Pos */ 52 /* */ 53 /* <Description> */ 54 /* The type FT_Pos is used to store vectorial coordinates. Depending */ 55 /* on the context, these can represent distances in integer font */ 56 /* units, or 16.16, or 26.6 fixed-point pixel coordinates. */ 57 /* */ 58 typedef signed long FT_Pos; 59 60 61 /*************************************************************************/ 62 /* */ 63 /* <Struct> */ 64 /* FT_Vector */ 65 /* */ 66 /* <Description> */ 67 /* A simple structure used to store a 2D vector; coordinates are of */ 68 /* the FT_Pos type. */ 69 /* */ 70 /* <Fields> */ 71 /* x :: The horizontal coordinate. */ 72 /* y :: The vertical coordinate. */ 73 /* */ 74 typedef struct FT_Vector_ 75 { 76 FT_Pos x; 77 FT_Pos y; 78 79 } FT_Vector; 80 81 82 /*************************************************************************/ 83 /* */ 84 /* <Struct> */ 85 /* FT_BBox */ 86 /* */ 87 /* <Description> */ 88 /* A structure used to hold an outline's bounding box, i.e., the */ 89 /* coordinates of its extrema in the horizontal and vertical */ 90 /* directions. */ 91 /* */ 92 /* <Fields> */ 93 /* xMin :: The horizontal minimum (left-most). */ 94 /* */ 95 /* yMin :: The vertical minimum (bottom-most). */ 96 /* */ 97 /* xMax :: The horizontal maximum (right-most). */ 98 /* */ 99 /* yMax :: The vertical maximum (top-most). */ 100 /* */ 101 /* <Note> */ 102 /* The bounding box is specified with the coordinates of the lower */ 103 /* left and the upper right corner. In PostScript, those values are */ 104 /* often called (llx,lly) and (urx,ury), respectively. */ 105 /* */ 106 /* If `yMin' is negative, this value gives the glyph's descender. */ 107 /* Otherwise, the glyph doesn't descend below the baseline. */ 108 /* Similarly, if `ymax' is positive, this value gives the glyph's */ 109 /* ascender. */ 110 /* */ 111 /* `xMin' gives the horizontal distance from the glyph's origin to */ 112 /* the left edge of the glyph's bounding box. If `xMin' is negative, */ 113 /* the glyph extends to the left of the origin. */ 114 /* */ 115 typedef struct FT_BBox_ 116 { 117 FT_Pos xMin, yMin; 118 FT_Pos xMax, yMax; 119 120 } FT_BBox; 121 122 123 /*************************************************************************/ 124 /* */ 125 /* <Enum> */ 126 /* FT_Pixel_Mode */ 127 /* */ 128 /* <Description> */ 129 /* An enumeration type used to describe the format of pixels in a */ 130 /* given bitmap. Note that additional formats may be added in the */ 131 /* future. */ 132 /* */ 133 /* <Values> */ 134 /* FT_PIXEL_MODE_NONE :: */ 135 /* Value~0 is reserved. */ 136 /* */ 137 /* FT_PIXEL_MODE_MONO :: */ 138 /* A monochrome bitmap, using 1~bit per pixel. Note that pixels */ 139 /* are stored in most-significant order (MSB), which means that */ 140 /* the left-most pixel in a byte has value 128. */ 141 /* */ 142 /* FT_PIXEL_MODE_GRAY :: */ 143 /* An 8-bit bitmap, generally used to represent anti-aliased glyph */ 144 /* images. Each pixel is stored in one byte. Note that the number */ 145 /* of `gray' levels is stored in the `num_grays' field of the */ 146 /* @FT_Bitmap structure (it generally is 256). */ 147 /* */ 148 /* FT_PIXEL_MODE_GRAY2 :: */ 149 /* A 2-bit per pixel bitmap, used to represent embedded */ 150 /* anti-aliased bitmaps in font files according to the OpenType */ 151 /* specification. We haven't found a single font using this */ 152 /* format, however. */ 153 /* */ 154 /* FT_PIXEL_MODE_GRAY4 :: */ 155 /* A 4-bit per pixel bitmap, representing embedded anti-aliased */ 156 /* bitmaps in font files according to the OpenType specification. */ 157 /* We haven't found a single font using this format, however. */ 158 /* */ 159 /* FT_PIXEL_MODE_LCD :: */ 160 /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */ 161 /* used for display on LCD displays; the bitmap is three times */ 162 /* wider than the original glyph image. See also */ 163 /* @FT_RENDER_MODE_LCD. */ 164 /* */ 165 /* FT_PIXEL_MODE_LCD_V :: */ 166 /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */ 167 /* used for display on rotated LCD displays; the bitmap is three */ 168 /* times taller than the original glyph image. See also */ 169 /* @FT_RENDER_MODE_LCD_V. */ 170 /* */ 171 /* FT_PIXEL_MODE_BGRA :: */ 172 /* An image with four 8-bit channels per pixel, representing a */ 173 /* color image (such as emoticons) with alpha channel. For each */ 174 /* pixel, the format is BGRA, which means, the blue channel comes */ 175 /* first in memory. The color channels are pre-multiplied and in */ 176 /* the sRGB colorspace. For example, full red at half-translucent */ 177 /* opacity will be represented as `00,00,80,80', not `00,00,FF,80'. */ 178 /* See also @FT_LOAD_COLOR. */ 179 /* */ 180 typedef enum FT_Pixel_Mode_ 181 { 182 FT_PIXEL_MODE_NONE = 0, 183 FT_PIXEL_MODE_MONO, 184 FT_PIXEL_MODE_GRAY, 185 FT_PIXEL_MODE_GRAY2, 186 FT_PIXEL_MODE_GRAY4, 187 FT_PIXEL_MODE_LCD, 188 FT_PIXEL_MODE_LCD_V, 189 FT_PIXEL_MODE_BGRA, 190 191 FT_PIXEL_MODE_MAX /* do not remove */ 192 193 } FT_Pixel_Mode; 194 195 196 /* these constants are deprecated; use the corresponding `FT_Pixel_Mode' */ 197 /* values instead. */ 198 #define ft_pixel_mode_none FT_PIXEL_MODE_NONE 199 #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO 200 #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY 201 #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2 202 #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4 203 204 205 /*************************************************************************/ 206 /* */ 207 /* <Struct> */ 208 /* FT_Bitmap */ 209 /* */ 210 /* <Description> */ 211 /* A structure used to describe a bitmap or pixmap to the raster. */ 212 /* Note that we now manage pixmaps of various depths through the */ 213 /* `pixel_mode' field. */ 214 /* */ 215 /* <Fields> */ 216 /* rows :: The number of bitmap rows. */ 217 /* */ 218 /* width :: The number of pixels in bitmap row. */ 219 /* */ 220 /* pitch :: The pitch's absolute value is the number of bytes */ 221 /* taken by one bitmap row, including padding. */ 222 /* However, the pitch is positive when the bitmap has */ 223 /* a `down' flow, and negative when it has an `up' */ 224 /* flow. In all cases, the pitch is an offset to add */ 225 /* to a bitmap pointer in order to go down one row. */ 226 /* */ 227 /* Note that `padding' means the alignment of a */ 228 /* bitmap to a byte border, and FreeType functions */ 229 /* normally align to the smallest possible integer */ 230 /* value. */ 231 /* */ 232 /* For the B/W rasterizer, `pitch' is always an even */ 233 /* number. */ 234 /* */ 235 /* To change the pitch of a bitmap (say, to make it a */ 236 /* multiple of 4), use @FT_Bitmap_Convert. */ 237 /* Alternatively, you might use callback functions to */ 238 /* directly render to the application's surface; see */ 239 /* the file `example2.cpp' in the tutorial for a */ 240 /* demonstration. */ 241 /* */ 242 /* buffer :: A typeless pointer to the bitmap buffer. This */ 243 /* value should be aligned on 32-bit boundaries in */ 244 /* most cases. */ 245 /* */ 246 /* num_grays :: This field is only used with */ 247 /* @FT_PIXEL_MODE_GRAY; it gives the number of gray */ 248 /* levels used in the bitmap. */ 249 /* */ 250 /* pixel_mode :: The pixel mode, i.e., how pixel bits are stored. */ 251 /* See @FT_Pixel_Mode for possible values. */ 252 /* */ 253 /* palette_mode :: This field is intended for paletted pixel modes; */ 254 /* it indicates how the palette is stored. Not */ 255 /* used currently. */ 256 /* */ 257 /* palette :: A typeless pointer to the bitmap palette; this */ 258 /* field is intended for paletted pixel modes. Not */ 259 /* used currently. */ 260 /* */ 261 typedef struct FT_Bitmap_ 262 { 263 unsigned int rows; 264 unsigned int width; 265 int pitch; 266 unsigned char* buffer; 267 unsigned short num_grays; 268 unsigned char pixel_mode; 269 unsigned char palette_mode; 270 void* palette; 271 272 } FT_Bitmap; 273 274 275 /*************************************************************************/ 276 /* */ 277 /* <Section> */ 278 /* outline_processing */ 279 /* */ 280 /*************************************************************************/ 281 282 283 /*************************************************************************/ 284 /* */ 285 /* <Struct> */ 286 /* FT_Outline */ 287 /* */ 288 /* <Description> */ 289 /* This structure is used to describe an outline to the scan-line */ 290 /* converter. */ 291 /* */ 292 /* <Fields> */ 293 /* n_contours :: The number of contours in the outline. */ 294 /* */ 295 /* n_points :: The number of points in the outline. */ 296 /* */ 297 /* points :: A pointer to an array of `n_points' @FT_Vector */ 298 /* elements, giving the outline's point coordinates. */ 299 /* */ 300 /* tags :: A pointer to an array of `n_points' chars, giving */ 301 /* each outline point's type. */ 302 /* */ 303 /* If bit~0 is unset, the point is `off' the curve, */ 304 /* i.e., a Bzier control point, while it is `on' if */ 305 /* set. */ 306 /* */ 307 /* Bit~1 is meaningful for `off' points only. If set, */ 308 /* it indicates a third-order Bzier arc control point; */ 309 /* and a second-order control point if unset. */ 310 /* */ 311 /* If bit~2 is set, bits 5-7 contain the drop-out mode */ 312 /* (as defined in the OpenType specification; the value */ 313 /* is the same as the argument to the SCANMODE */ 314 /* instruction). */ 315 /* */ 316 /* Bits 3 and~4 are reserved for internal purposes. */ 317 /* */ 318 /* contours :: An array of `n_contours' shorts, giving the end */ 319 /* point of each contour within the outline. For */ 320 /* example, the first contour is defined by the points */ 321 /* `0' to `contours[0]', the second one is defined by */ 322 /* the points `contours[0]+1' to `contours[1]', etc. */ 323 /* */ 324 /* flags :: A set of bit flags used to characterize the outline */ 325 /* and give hints to the scan-converter and hinter on */ 326 /* how to convert/grid-fit it. See @FT_OUTLINE_XXX. */ 327 /* */ 328 /* <Note> */ 329 /* The B/W rasterizer only checks bit~2 in the `tags' array for the */ 330 /* first point of each contour. The drop-out mode as given with */ 331 /* @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and */ 332 /* @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden. */ 333 /* */ 334 typedef struct FT_Outline_ 335 { 336 short n_contours; /* number of contours in glyph */ 337 short n_points; /* number of points in the glyph */ 338 339 FT_Vector* points; /* the outline's points */ 340 char* tags; /* the points flags */ 341 short* contours; /* the contour end points */ 342 343 int flags; /* outline masks */ 344 345 } FT_Outline; 346 347 /* */ 348 349 /* Following limits must be consistent with */ 350 /* FT_Outline.{n_contours,n_points} */ 351 #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX 352 #define FT_OUTLINE_POINTS_MAX SHRT_MAX 353 354 355 /*************************************************************************/ 356 /* */ 357 /* <Enum> */ 358 /* FT_OUTLINE_XXX */ 359 /* */ 360 /* <Description> */ 361 /* A list of bit-field constants use for the flags in an outline's */ 362 /* `flags' field. */ 363 /* */ 364 /* <Values> */ 365 /* FT_OUTLINE_NONE :: */ 366 /* Value~0 is reserved. */ 367 /* */ 368 /* FT_OUTLINE_OWNER :: */ 369 /* If set, this flag indicates that the outline's field arrays */ 370 /* (i.e., `points', `flags', and `contours') are `owned' by the */ 371 /* outline object, and should thus be freed when it is destroyed. */ 372 /* */ 373 /* FT_OUTLINE_EVEN_ODD_FILL :: */ 374 /* By default, outlines are filled using the non-zero winding rule. */ 375 /* If set to 1, the outline will be filled using the even-odd fill */ 376 /* rule (only works with the smooth rasterizer). */ 377 /* */ 378 /* FT_OUTLINE_REVERSE_FILL :: */ 379 /* By default, outside contours of an outline are oriented in */ 380 /* clock-wise direction, as defined in the TrueType specification. */ 381 /* This flag is set if the outline uses the opposite direction */ 382 /* (typically for Type~1 fonts). This flag is ignored by the scan */ 383 /* converter. */ 384 /* */ 385 /* FT_OUTLINE_IGNORE_DROPOUTS :: */ 386 /* By default, the scan converter will try to detect drop-outs in */ 387 /* an outline and correct the glyph bitmap to ensure consistent */ 388 /* shape continuity. If set, this flag hints the scan-line */ 389 /* converter to ignore such cases. See below for more information. */ 390 /* */ 391 /* FT_OUTLINE_SMART_DROPOUTS :: */ 392 /* Select smart dropout control. If unset, use simple dropout */ 393 /* control. Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See */ 394 /* below for more information. */ 395 /* */ 396 /* FT_OUTLINE_INCLUDE_STUBS :: */ 397 /* If set, turn pixels on for `stubs', otherwise exclude them. */ 398 /* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for */ 399 /* more information. */ 400 /* */ 401 /* FT_OUTLINE_HIGH_PRECISION :: */ 402 /* This flag indicates that the scan-line converter should try to */ 403 /* convert this outline to bitmaps with the highest possible */ 404 /* quality. It is typically set for small character sizes. Note */ 405 /* that this is only a hint that might be completely ignored by a */ 406 /* given scan-converter. */ 407 /* */ 408 /* FT_OUTLINE_SINGLE_PASS :: */ 409 /* This flag is set to force a given scan-converter to only use a */ 410 /* single pass over the outline to render a bitmap glyph image. */ 411 /* Normally, it is set for very large character sizes. It is only */ 412 /* a hint that might be completely ignored by a given */ 413 /* scan-converter. */ 414 /* */ 415 /* <Note> */ 416 /* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */ 417 /* and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth */ 418 /* rasterizer. */ 419 /* */ 420 /* There exists a second mechanism to pass the drop-out mode to the */ 421 /* B/W rasterizer; see the `tags' field in @FT_Outline. */ 422 /* */ 423 /* Please refer to the description of the `SCANTYPE' instruction in */ 424 /* the OpenType specification (in file `ttinst1.doc') how simple */ 425 /* drop-outs, smart drop-outs, and stubs are defined. */ 426 /* */ 427 #define FT_OUTLINE_NONE 0x0 428 #define FT_OUTLINE_OWNER 0x1 429 #define FT_OUTLINE_EVEN_ODD_FILL 0x2 430 #define FT_OUTLINE_REVERSE_FILL 0x4 431 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8 432 #define FT_OUTLINE_SMART_DROPOUTS 0x10 433 #define FT_OUTLINE_INCLUDE_STUBS 0x20 434 435 #define FT_OUTLINE_HIGH_PRECISION 0x100 436 #define FT_OUTLINE_SINGLE_PASS 0x200 437 438 439 /* these constants are deprecated; use the corresponding */ 440 /* `FT_OUTLINE_XXX' values instead */ 441 #define ft_outline_none FT_OUTLINE_NONE 442 #define ft_outline_owner FT_OUTLINE_OWNER 443 #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL 444 #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL 445 #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS 446 #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION 447 #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS 448 449 /* */ 450 451 #define FT_CURVE_TAG( flag ) ( flag & 3 ) 452 453 #define FT_CURVE_TAG_ON 1 454 #define FT_CURVE_TAG_CONIC 0 455 #define FT_CURVE_TAG_CUBIC 2 456 457 #define FT_CURVE_TAG_HAS_SCANMODE 4 458 459 #define FT_CURVE_TAG_TOUCH_X 8 /* reserved for the TrueType hinter */ 460 #define FT_CURVE_TAG_TOUCH_Y 16 /* reserved for the TrueType hinter */ 461 462 #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \ 463 FT_CURVE_TAG_TOUCH_Y ) 464 465 #define FT_Curve_Tag_On FT_CURVE_TAG_ON 466 #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC 467 #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC 468 #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X 469 #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y 470 471 472 /*************************************************************************/ 473 /* */ 474 /* <FuncType> */ 475 /* FT_Outline_MoveToFunc */ 476 /* */ 477 /* <Description> */ 478 /* A function pointer type used to describe the signature of a `move */ 479 /* to' function during outline walking/decomposition. */ 480 /* */ 481 /* A `move to' is emitted to start a new contour in an outline. */ 482 /* */ 483 /* <Input> */ 484 /* to :: A pointer to the target point of the `move to'. */ 485 /* */ 486 /* user :: A typeless pointer, which is passed from the caller of the */ 487 /* decomposition function. */ 488 /* */ 489 /* <Return> */ 490 /* Error code. 0~means success. */ 491 /* */ 492 typedef int 493 (*FT_Outline_MoveToFunc)( const FT_Vector* to, 494 void* user ); 495 496 #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc 497 498 499 /*************************************************************************/ 500 /* */ 501 /* <FuncType> */ 502 /* FT_Outline_LineToFunc */ 503 /* */ 504 /* <Description> */ 505 /* A function pointer type used to describe the signature of a `line */ 506 /* to' function during outline walking/decomposition. */ 507 /* */ 508 /* A `line to' is emitted to indicate a segment in the outline. */ 509 /* */ 510 /* <Input> */ 511 /* to :: A pointer to the target point of the `line to'. */ 512 /* */ 513 /* user :: A typeless pointer, which is passed from the caller of the */ 514 /* decomposition function. */ 515 /* */ 516 /* <Return> */ 517 /* Error code. 0~means success. */ 518 /* */ 519 typedef int 520 (*FT_Outline_LineToFunc)( const FT_Vector* to, 521 void* user ); 522 523 #define FT_Outline_LineTo_Func FT_Outline_LineToFunc 524 525 526 /*************************************************************************/ 527 /* */ 528 /* <FuncType> */ 529 /* FT_Outline_ConicToFunc */ 530 /* */ 531 /* <Description> */ 532 /* A function pointer type used to describe the signature of a `conic */ 533 /* to' function during outline walking or decomposition. */ 534 /* */ 535 /* A `conic to' is emitted to indicate a second-order Bzier arc in */ 536 /* the outline. */ 537 /* */ 538 /* <Input> */ 539 /* control :: An intermediate control point between the last position */ 540 /* and the new target in `to'. */ 541 /* */ 542 /* to :: A pointer to the target end point of the conic arc. */ 543 /* */ 544 /* user :: A typeless pointer, which is passed from the caller of */ 545 /* the decomposition function. */ 546 /* */ 547 /* <Return> */ 548 /* Error code. 0~means success. */ 549 /* */ 550 typedef int 551 (*FT_Outline_ConicToFunc)( const FT_Vector* control, 552 const FT_Vector* to, 553 void* user ); 554 555 #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc 556 557 558 /*************************************************************************/ 559 /* */ 560 /* <FuncType> */ 561 /* FT_Outline_CubicToFunc */ 562 /* */ 563 /* <Description> */ 564 /* A function pointer type used to describe the signature of a `cubic */ 565 /* to' function during outline walking or decomposition. */ 566 /* */ 567 /* A `cubic to' is emitted to indicate a third-order Bzier arc. */ 568 /* */ 569 /* <Input> */ 570 /* control1 :: A pointer to the first Bzier control point. */ 571 /* */ 572 /* control2 :: A pointer to the second Bzier control point. */ 573 /* */ 574 /* to :: A pointer to the target end point. */ 575 /* */ 576 /* user :: A typeless pointer, which is passed from the caller of */ 577 /* the decomposition function. */ 578 /* */ 579 /* <Return> */ 580 /* Error code. 0~means success. */ 581 /* */ 582 typedef int 583 (*FT_Outline_CubicToFunc)( const FT_Vector* control1, 584 const FT_Vector* control2, 585 const FT_Vector* to, 586 void* user ); 587 588 #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc 589 590 591 /*************************************************************************/ 592 /* */ 593 /* <Struct> */ 594 /* FT_Outline_Funcs */ 595 /* */ 596 /* <Description> */ 597 /* A structure to hold various function pointers used during outline */ 598 /* decomposition in order to emit segments, conic, and cubic Bziers. */ 599 /* */ 600 /* <Fields> */ 601 /* move_to :: The `move to' emitter. */ 602 /* */ 603 /* line_to :: The segment emitter. */ 604 /* */ 605 /* conic_to :: The second-order Bzier arc emitter. */ 606 /* */ 607 /* cubic_to :: The third-order Bzier arc emitter. */ 608 /* */ 609 /* shift :: The shift that is applied to coordinates before they */ 610 /* are sent to the emitter. */ 611 /* */ 612 /* delta :: The delta that is applied to coordinates before they */ 613 /* are sent to the emitter, but after the shift. */ 614 /* */ 615 /* <Note> */ 616 /* The point coordinates sent to the emitters are the transformed */ 617 /* version of the original coordinates (this is important for high */ 618 /* accuracy during scan-conversion). The transformation is simple: */ 619 /* */ 620 /* { */ 621 /* x' = (x << shift) - delta */ 622 /* y' = (x << shift) - delta */ 623 /* } */ 624 /* */ 625 /* Set the values of `shift' and `delta' to~0 to get the original */ 626 /* point coordinates. */ 627 /* */ 628 typedef struct FT_Outline_Funcs_ 629 { 630 FT_Outline_MoveToFunc move_to; 631 FT_Outline_LineToFunc line_to; 632 FT_Outline_ConicToFunc conic_to; 633 FT_Outline_CubicToFunc cubic_to; 634 635 int shift; 636 FT_Pos delta; 637 638 } FT_Outline_Funcs; 639 640 641 /*************************************************************************/ 642 /* */ 643 /* <Section> */ 644 /* basic_types */ 645 /* */ 646 /*************************************************************************/ 647 648 649 /*************************************************************************/ 650 /* */ 651 /* <Macro> */ 652 /* FT_IMAGE_TAG */ 653 /* */ 654 /* <Description> */ 655 /* This macro converts four-letter tags to an unsigned long type. */ 656 /* */ 657 /* <Note> */ 658 /* Since many 16-bit compilers don't like 32-bit enumerations, you */ 659 /* should redefine this macro in case of problems to something like */ 660 /* this: */ 661 /* */ 662 /* { */ 663 /* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value */ 664 /* } */ 665 /* */ 666 /* to get a simple enumeration without assigning special numbers. */ 667 /* */ 668 #ifndef FT_IMAGE_TAG 669 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \ 670 value = ( ( (unsigned long)_x1 << 24 ) | \ 671 ( (unsigned long)_x2 << 16 ) | \ 672 ( (unsigned long)_x3 << 8 ) | \ 673 (unsigned long)_x4 ) 674 #endif /* FT_IMAGE_TAG */ 675 676 677 /*************************************************************************/ 678 /* */ 679 /* <Enum> */ 680 /* FT_Glyph_Format */ 681 /* */ 682 /* <Description> */ 683 /* An enumeration type used to describe the format of a given glyph */ 684 /* image. Note that this version of FreeType only supports two image */ 685 /* formats, even though future font drivers will be able to register */ 686 /* their own format. */ 687 /* */ 688 /* <Values> */ 689 /* FT_GLYPH_FORMAT_NONE :: */ 690 /* The value~0 is reserved. */ 691 /* */ 692 /* FT_GLYPH_FORMAT_COMPOSITE :: */ 693 /* The glyph image is a composite of several other images. This */ 694 /* format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to */ 695 /* report compound glyphs (like accented characters). */ 696 /* */ 697 /* FT_GLYPH_FORMAT_BITMAP :: */ 698 /* The glyph image is a bitmap, and can be described as an */ 699 /* @FT_Bitmap. You generally need to access the `bitmap' field of */ 700 /* the @FT_GlyphSlotRec structure to read it. */ 701 /* */ 702 /* FT_GLYPH_FORMAT_OUTLINE :: */ 703 /* The glyph image is a vectorial outline made of line segments */ 704 /* and Bzier arcs; it can be described as an @FT_Outline; you */ 705 /* generally want to access the `outline' field of the */ 706 /* @FT_GlyphSlotRec structure to read it. */ 707 /* */ 708 /* FT_GLYPH_FORMAT_PLOTTER :: */ 709 /* The glyph image is a vectorial path with no inside and outside */ 710 /* contours. Some Type~1 fonts, like those in the Hershey family, */ 711 /* contain glyphs in this format. These are described as */ 712 /* @FT_Outline, but FreeType isn't currently capable of rendering */ 713 /* them correctly. */ 714 /* */ 715 typedef enum FT_Glyph_Format_ 716 { 717 FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ), 718 719 FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ), 720 FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ), 721 FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ), 722 FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' ) 723 724 } FT_Glyph_Format; 725 726 727 /* these constants are deprecated; use the corresponding */ 728 /* `FT_Glyph_Format' values instead. */ 729 #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE 730 #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE 731 #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP 732 #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE 733 #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER 734 735 736 /*************************************************************************/ 737 /*************************************************************************/ 738 /*************************************************************************/ 739 /***** *****/ 740 /***** R A S T E R D E F I N I T I O N S *****/ 741 /***** *****/ 742 /*************************************************************************/ 743 /*************************************************************************/ 744 /*************************************************************************/ 745 746 747 /*************************************************************************/ 748 /* */ 749 /* A raster is a scan converter, in charge of rendering an outline into */ 750 /* a a bitmap. This section contains the public API for rasters. */ 751 /* */ 752 /* Note that in FreeType 2, all rasters are now encapsulated within */ 753 /* specific modules called `renderers'. See `ftrender.h' for more */ 754 /* details on renderers. */ 755 /* */ 756 /*************************************************************************/ 757 758 759 /*************************************************************************/ 760 /* */ 761 /* <Section> */ 762 /* raster */ 763 /* */ 764 /* <Title> */ 765 /* Scanline Converter */ 766 /* */ 767 /* <Abstract> */ 768 /* How vectorial outlines are converted into bitmaps and pixmaps. */ 769 /* */ 770 /* <Description> */ 771 /* This section contains technical definitions. */ 772 /* */ 773 /* <Order> */ 774 /* FT_Raster */ 775 /* FT_Span */ 776 /* FT_SpanFunc */ 777 /* */ 778 /* FT_Raster_Params */ 779 /* FT_RASTER_FLAG_XXX */ 780 /* */ 781 /* FT_Raster_NewFunc */ 782 /* FT_Raster_DoneFunc */ 783 /* FT_Raster_ResetFunc */ 784 /* FT_Raster_SetModeFunc */ 785 /* FT_Raster_RenderFunc */ 786 /* FT_Raster_Funcs */ 787 /* */ 788 /*************************************************************************/ 789 790 791 /*************************************************************************/ 792 /* */ 793 /* <Type> */ 794 /* FT_Raster */ 795 /* */ 796 /* <Description> */ 797 /* An opaque handle (pointer) to a raster object. Each object can be */ 798 /* used independently to convert an outline into a bitmap or pixmap. */ 799 /* */ 800 typedef struct FT_RasterRec_* FT_Raster; 801 802 803 /*************************************************************************/ 804 /* */ 805 /* <Struct> */ 806 /* FT_Span */ 807 /* */ 808 /* <Description> */ 809 /* A structure used to model a single span of gray pixels when */ 810 /* rendering an anti-aliased bitmap. */ 811 /* */ 812 /* <Fields> */ 813 /* x :: The span's horizontal start position. */ 814 /* */ 815 /* len :: The span's length in pixels. */ 816 /* */ 817 /* coverage :: The span color/coverage, ranging from 0 (background) */ 818 /* to 255 (foreground). */ 819 /* */ 820 /* <Note> */ 821 /* This structure is used by the span drawing callback type named */ 822 /* @FT_SpanFunc that takes the y~coordinate of the span as a */ 823 /* parameter. */ 824 /* */ 825 /* The coverage value is always between 0 and 255. If you want less */ 826 /* gray values, the callback function has to reduce them. */ 827 /* */ 828 typedef struct FT_Span_ 829 { 830 short x; 831 unsigned short len; 832 unsigned char coverage; 833 834 } FT_Span; 835 836 837 /*************************************************************************/ 838 /* */ 839 /* <FuncType> */ 840 /* FT_SpanFunc */ 841 /* */ 842 /* <Description> */ 843 /* A function used as a call-back by the anti-aliased renderer in */ 844 /* order to let client applications draw themselves the gray pixel */ 845 /* spans on each scan line. */ 846 /* */ 847 /* <Input> */ 848 /* y :: The scanline's y~coordinate. */ 849 /* */ 850 /* count :: The number of spans to draw on this scanline. */ 851 /* */ 852 /* spans :: A table of `count' spans to draw on the scanline. */ 853 /* */ 854 /* user :: User-supplied data that is passed to the callback. */ 855 /* */ 856 /* <Note> */ 857 /* This callback allows client applications to directly render the */ 858 /* gray spans of the anti-aliased bitmap to any kind of surfaces. */ 859 /* */ 860 /* This can be used to write anti-aliased outlines directly to a */ 861 /* given background bitmap, and even perform translucency. */ 862 /* */ 863 /* Note that the `count' field cannot be greater than a fixed value */ 864 /* defined by the `FT_MAX_GRAY_SPANS' configuration macro in */ 865 /* `ftoption.h'. By default, this value is set to~32, which means */ 866 /* that if there are more than 32~spans on a given scanline, the */ 867 /* callback is called several times with the same `y' parameter in */ 868 /* order to draw all callbacks. */ 869 /* */ 870 /* Otherwise, the callback is only called once per scan-line, and */ 871 /* only for those scanlines that do have `gray' pixels on them. */ 872 /* */ 873 typedef void 874 (*FT_SpanFunc)( int y, 875 int count, 876 const FT_Span* spans, 877 void* user ); 878 879 #define FT_Raster_Span_Func FT_SpanFunc 880 881 882 /*************************************************************************/ 883 /* */ 884 /* <FuncType> */ 885 /* FT_Raster_BitTest_Func */ 886 /* */ 887 /* <Description> */ 888 /* Deprecated, unimplemented. */ 889 /* */ 890 typedef int 891 (*FT_Raster_BitTest_Func)( int y, 892 int x, 893 void* user ); 894 895 896 /*************************************************************************/ 897 /* */ 898 /* <FuncType> */ 899 /* FT_Raster_BitSet_Func */ 900 /* */ 901 /* <Description> */ 902 /* Deprecated, unimplemented. */ 903 /* */ 904 typedef void 905 (*FT_Raster_BitSet_Func)( int y, 906 int x, 907 void* user ); 908 909 910 /*************************************************************************/ 911 /* */ 912 /* <Enum> */ 913 /* FT_RASTER_FLAG_XXX */ 914 /* */ 915 /* <Description> */ 916 /* A list of bit flag constants as used in the `flags' field of a */ 917 /* @FT_Raster_Params structure. */ 918 /* */ 919 /* <Values> */ 920 /* FT_RASTER_FLAG_DEFAULT :: This value is 0. */ 921 /* */ 922 /* FT_RASTER_FLAG_AA :: This flag is set to indicate that an */ 923 /* anti-aliased glyph image should be */ 924 /* generated. Otherwise, it will be */ 925 /* monochrome (1-bit). */ 926 /* */ 927 /* FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */ 928 /* rendering. In this mode, client */ 929 /* applications must provide their own span */ 930 /* callback. This lets them directly */ 931 /* draw or compose over an existing bitmap. */ 932 /* If this bit is not set, the target */ 933 /* pixmap's buffer _must_ be zeroed before */ 934 /* rendering. */ 935 /* */ 936 /* Direct rendering is only possible with */ 937 /* anti-aliased glyphs. */ 938 /* */ 939 /* FT_RASTER_FLAG_CLIP :: This flag is only used in direct */ 940 /* rendering mode. If set, the output will */ 941 /* be clipped to a box specified in the */ 942 /* `clip_box' field of the */ 943 /* @FT_Raster_Params structure. */ 944 /* */ 945 /* Note that by default, the glyph bitmap */ 946 /* is clipped to the target pixmap, except */ 947 /* in direct rendering mode where all spans */ 948 /* are generated if no clipping box is set. */ 949 /* */ 950 #define FT_RASTER_FLAG_DEFAULT 0x0 951 #define FT_RASTER_FLAG_AA 0x1 952 #define FT_RASTER_FLAG_DIRECT 0x2 953 #define FT_RASTER_FLAG_CLIP 0x4 954 955 /* these constants are deprecated; use the corresponding */ 956 /* `FT_RASTER_FLAG_XXX' values instead */ 957 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT 958 #define ft_raster_flag_aa FT_RASTER_FLAG_AA 959 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT 960 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP 961 962 963 /*************************************************************************/ 964 /* */ 965 /* <Struct> */ 966 /* FT_Raster_Params */ 967 /* */ 968 /* <Description> */ 969 /* A structure to hold the arguments used by a raster's render */ 970 /* function. */ 971 /* */ 972 /* <Fields> */ 973 /* target :: The target bitmap. */ 974 /* */ 975 /* source :: A pointer to the source glyph image (e.g., an */ 976 /* @FT_Outline). */ 977 /* */ 978 /* flags :: The rendering flags. */ 979 /* */ 980 /* gray_spans :: The gray span drawing callback. */ 981 /* */ 982 /* black_spans :: Unused. */ 983 /* */ 984 /* bit_test :: Unused. */ 985 /* */ 986 /* bit_set :: Unused. */ 987 /* */ 988 /* user :: User-supplied data that is passed to each drawing */ 989 /* callback. */ 990 /* */ 991 /* clip_box :: An optional clipping box. It is only used in */ 992 /* direct rendering mode. Note that coordinates here */ 993 /* should be expressed in _integer_ pixels (and not in */ 994 /* 26.6 fixed-point units). */ 995 /* */ 996 /* <Note> */ 997 /* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA */ 998 /* bit flag is set in the `flags' field, otherwise a monochrome */ 999 /* bitmap is generated. */ 1000 /* */ 1001 /* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */ 1002 /* raster will call the `gray_spans' callback to draw gray pixel */ 1003 /* spans. This allows direct composition over a pre-existing bitmap */ 1004 /* through user-provided callbacks to perform the span drawing and */ 1005 /* composition. Not supported by the monochrome rasterizer. */ 1006 /* */ 1007 typedef struct FT_Raster_Params_ 1008 { 1009 const FT_Bitmap* target; 1010 const void* source; 1011 int flags; 1012 FT_SpanFunc gray_spans; 1013 FT_SpanFunc black_spans; /* unused */ 1014 FT_Raster_BitTest_Func bit_test; /* unused */ 1015 FT_Raster_BitSet_Func bit_set; /* unused */ 1016 void* user; 1017 FT_BBox clip_box; 1018 1019 } FT_Raster_Params; 1020 1021 1022 /*************************************************************************/ 1023 /* */ 1024 /* <FuncType> */ 1025 /* FT_Raster_NewFunc */ 1026 /* */ 1027 /* <Description> */ 1028 /* A function used to create a new raster object. */ 1029 /* */ 1030 /* <Input> */ 1031 /* memory :: A handle to the memory allocator. */ 1032 /* */ 1033 /* <Output> */ 1034 /* raster :: A handle to the new raster object. */ 1035 /* */ 1036 /* <Return> */ 1037 /* Error code. 0~means success. */ 1038 /* */ 1039 /* <Note> */ 1040 /* The `memory' parameter is a typeless pointer in order to avoid */ 1041 /* un-wanted dependencies on the rest of the FreeType code. In */ 1042 /* practice, it is an @FT_Memory object, i.e., a handle to the */ 1043 /* standard FreeType memory allocator. However, this field can be */ 1044 /* completely ignored by a given raster implementation. */ 1045 /* */ 1046 typedef int 1047 (*FT_Raster_NewFunc)( void* memory, 1048 FT_Raster* raster ); 1049 1050 #define FT_Raster_New_Func FT_Raster_NewFunc 1051 1052 1053 /*************************************************************************/ 1054 /* */ 1055 /* <FuncType> */ 1056 /* FT_Raster_DoneFunc */ 1057 /* */ 1058 /* <Description> */ 1059 /* A function used to destroy a given raster object. */ 1060 /* */ 1061 /* <Input> */ 1062 /* raster :: A handle to the raster object. */ 1063 /* */ 1064 typedef void 1065 (*FT_Raster_DoneFunc)( FT_Raster raster ); 1066 1067 #define FT_Raster_Done_Func FT_Raster_DoneFunc 1068 1069 1070 /*************************************************************************/ 1071 /* */ 1072 /* <FuncType> */ 1073 /* FT_Raster_ResetFunc */ 1074 /* */ 1075 /* <Description> */ 1076 /* FreeType used to provide an area of memory called the `render */ 1077 /* pool' available to all registered rasters. This was not thread */ 1078 /* safe however and now FreeType never allocates this pool. NULL */ 1079 /* is always passed in as pool_base. */ 1080 /* */ 1081 /* This function is called each time the render pool changes, or just */ 1082 /* after a new raster object is created. */ 1083 /* */ 1084 /* <Input> */ 1085 /* raster :: A handle to the new raster object. */ 1086 /* */ 1087 /* pool_base :: The address in memory of the render pool. */ 1088 /* */ 1089 /* pool_size :: The size in bytes of the render pool. */ 1090 /* */ 1091 /* <Note> */ 1092 /* Rasters should ignore the render pool and rely on dynamic or stack */ 1093 /* allocation if they want to (a handle to the memory allocator is */ 1094 /* passed to the raster constructor). */ 1095 /* */ 1096 typedef void 1097 (*FT_Raster_ResetFunc)( FT_Raster raster, 1098 unsigned char* pool_base, 1099 unsigned long pool_size ); 1100 1101 #define FT_Raster_Reset_Func FT_Raster_ResetFunc 1102 1103 1104 /*************************************************************************/ 1105 /* */ 1106 /* <FuncType> */ 1107 /* FT_Raster_SetModeFunc */ 1108 /* */ 1109 /* <Description> */ 1110 /* This function is a generic facility to change modes or attributes */ 1111 /* in a given raster. This can be used for debugging purposes, or */ 1112 /* simply to allow implementation-specific `features' in a given */ 1113 /* raster module. */ 1114 /* */ 1115 /* <Input> */ 1116 /* raster :: A handle to the new raster object. */ 1117 /* */ 1118 /* mode :: A 4-byte tag used to name the mode or property. */ 1119 /* */ 1120 /* args :: A pointer to the new mode/property to use. */ 1121 /* */ 1122 typedef int 1123 (*FT_Raster_SetModeFunc)( FT_Raster raster, 1124 unsigned long mode, 1125 void* args ); 1126 1127 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc 1128 1129 1130 /*************************************************************************/ 1131 /* */ 1132 /* <FuncType> */ 1133 /* FT_Raster_RenderFunc */ 1134 /* */ 1135 /* <Description> */ 1136 /* Invoke a given raster to scan-convert a given glyph image into a */ 1137 /* target bitmap. */ 1138 /* */ 1139 /* <Input> */ 1140 /* raster :: A handle to the raster object. */ 1141 /* */ 1142 /* params :: A pointer to an @FT_Raster_Params structure used to */ 1143 /* store the rendering parameters. */ 1144 /* */ 1145 /* <Return> */ 1146 /* Error code. 0~means success. */ 1147 /* */ 1148 /* <Note> */ 1149 /* The exact format of the source image depends on the raster's glyph */ 1150 /* format defined in its @FT_Raster_Funcs structure. It can be an */ 1151 /* @FT_Outline or anything else in order to support a large array of */ 1152 /* glyph formats. */ 1153 /* */ 1154 /* Note also that the render function can fail and return a */ 1155 /* `FT_Err_Unimplemented_Feature' error code if the raster used does */ 1156 /* not support direct composition. */ 1157 /* */ 1158 /* XXX: For now, the standard raster doesn't support direct */ 1159 /* composition but this should change for the final release (see */ 1160 /* the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c' */ 1161 /* for examples of distinct implementations that support direct */ 1162 /* composition). */ 1163 /* */ 1164 typedef int 1165 (*FT_Raster_RenderFunc)( FT_Raster raster, 1166 const FT_Raster_Params* params ); 1167 1168 #define FT_Raster_Render_Func FT_Raster_RenderFunc 1169 1170 1171 /*************************************************************************/ 1172 /* */ 1173 /* <Struct> */ 1174 /* FT_Raster_Funcs */ 1175 /* */ 1176 /* <Description> */ 1177 /* A structure used to describe a given raster class to the library. */ 1178 /* */ 1179 /* <Fields> */ 1180 /* glyph_format :: The supported glyph format for this raster. */ 1181 /* */ 1182 /* raster_new :: The raster constructor. */ 1183 /* */ 1184 /* raster_reset :: Used to reset the render pool within the raster. */ 1185 /* */ 1186 /* raster_render :: A function to render a glyph into a given bitmap. */ 1187 /* */ 1188 /* raster_done :: The raster destructor. */ 1189 /* */ 1190 typedef struct FT_Raster_Funcs_ 1191 { 1192 FT_Glyph_Format glyph_format; 1193 FT_Raster_NewFunc raster_new; 1194 FT_Raster_ResetFunc raster_reset; 1195 FT_Raster_SetModeFunc raster_set_mode; 1196 FT_Raster_RenderFunc raster_render; 1197 FT_Raster_DoneFunc raster_done; 1198 1199 } FT_Raster_Funcs; 1200 1201 /* */ 1202 1203 1204 FT_END_HEADER 1205 1206 #endif /* __FTIMAGE_H__ */ 1207 1208 1209 /* END */ 1210 1211 1212 /* Local Variables: */ 1213 /* coding: utf-8 */ 1214 /* End: */ 1215
