1 /***************************************************************************/ 2 /* */ 3 /* ftimage.h */ 4 /* */ 5 /* FreeType glyph image formats and default raster interface */ 6 /* (specification). */ 7 /* */ 8 /* Copyright 1996-2018 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 /* [Since 2.5] An image with four 8-bit channels per pixel, */ 173 /* representing a color image (such as emoticons) with alpha */ 174 /* channel. For each pixel, the format is BGRA, which means, the */ 175 /* blue channel comes first in memory. The color channels are */ 176 /* pre-multiplied and in the sRGB colorspace. For example, full */ 177 /* red at half-translucent opacity will be represented as */ 178 /* `00,00,80,80', not `00,00,FF,80'. 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 Bezier 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 Bezier 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 Bezier 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 Bezier arc. */ 568 /* */ 569 /* <Input> */ 570 /* control1 :: A pointer to the first Bezier control point. */ 571 /* */ 572 /* control2 :: A pointer to the second Bezier 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 Beziers. */ 599 /* */ 600 /* <Fields> */ 601 /* move_to :: The `move to' emitter. */ 602 /* */ 603 /* line_to :: The segment emitter. */ 604 /* */ 605 /* conic_to :: The second-order Bezier arc emitter. */ 606 /* */ 607 /* cubic_to :: The third-order Bezier 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' = (y << 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 Bezier 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 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 typedef void 864 (*FT_SpanFunc)( int y, 865 int count, 866 const FT_Span* spans, 867 void* user ); 868 869 #define FT_Raster_Span_Func FT_SpanFunc 870 871 872 /*************************************************************************/ 873 /* */ 874 /* <FuncType> */ 875 /* FT_Raster_BitTest_Func */ 876 /* */ 877 /* <Description> */ 878 /* Deprecated, unimplemented. */ 879 /* */ 880 typedef int 881 (*FT_Raster_BitTest_Func)( int y, 882 int x, 883 void* user ); 884 885 886 /*************************************************************************/ 887 /* */ 888 /* <FuncType> */ 889 /* FT_Raster_BitSet_Func */ 890 /* */ 891 /* <Description> */ 892 /* Deprecated, unimplemented. */ 893 /* */ 894 typedef void 895 (*FT_Raster_BitSet_Func)( int y, 896 int x, 897 void* user ); 898 899 900 /*************************************************************************/ 901 /* */ 902 /* <Enum> */ 903 /* FT_RASTER_FLAG_XXX */ 904 /* */ 905 /* <Description> */ 906 /* A list of bit flag constants as used in the `flags' field of a */ 907 /* @FT_Raster_Params structure. */ 908 /* */ 909 /* <Values> */ 910 /* FT_RASTER_FLAG_DEFAULT :: This value is 0. */ 911 /* */ 912 /* FT_RASTER_FLAG_AA :: This flag is set to indicate that an */ 913 /* anti-aliased glyph image should be */ 914 /* generated. Otherwise, it will be */ 915 /* monochrome (1-bit). */ 916 /* */ 917 /* FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */ 918 /* rendering. In this mode, client */ 919 /* applications must provide their own span */ 920 /* callback. This lets them directly */ 921 /* draw or compose over an existing bitmap. */ 922 /* If this bit is not set, the target */ 923 /* pixmap's buffer _must_ be zeroed before */ 924 /* rendering. */ 925 /* */ 926 /* Direct rendering is only possible with */ 927 /* anti-aliased glyphs. */ 928 /* */ 929 /* FT_RASTER_FLAG_CLIP :: This flag is only used in direct */ 930 /* rendering mode. If set, the output will */ 931 /* be clipped to a box specified in the */ 932 /* `clip_box' field of the */ 933 /* @FT_Raster_Params structure. */ 934 /* */ 935 /* Note that by default, the glyph bitmap */ 936 /* is clipped to the target pixmap, except */ 937 /* in direct rendering mode where all spans */ 938 /* are generated if no clipping box is set. */ 939 /* */ 940 #define FT_RASTER_FLAG_DEFAULT 0x0 941 #define FT_RASTER_FLAG_AA 0x1 942 #define FT_RASTER_FLAG_DIRECT 0x2 943 #define FT_RASTER_FLAG_CLIP 0x4 944 945 /* these constants are deprecated; use the corresponding */ 946 /* `FT_RASTER_FLAG_XXX' values instead */ 947 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT 948 #define ft_raster_flag_aa FT_RASTER_FLAG_AA 949 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT 950 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP 951 952 953 /*************************************************************************/ 954 /* */ 955 /* <Struct> */ 956 /* FT_Raster_Params */ 957 /* */ 958 /* <Description> */ 959 /* A structure to hold the arguments used by a raster's render */ 960 /* function. */ 961 /* */ 962 /* <Fields> */ 963 /* target :: The target bitmap. */ 964 /* */ 965 /* source :: A pointer to the source glyph image (e.g., an */ 966 /* @FT_Outline). */ 967 /* */ 968 /* flags :: The rendering flags. */ 969 /* */ 970 /* gray_spans :: The gray span drawing callback. */ 971 /* */ 972 /* black_spans :: Unused. */ 973 /* */ 974 /* bit_test :: Unused. */ 975 /* */ 976 /* bit_set :: Unused. */ 977 /* */ 978 /* user :: User-supplied data that is passed to each drawing */ 979 /* callback. */ 980 /* */ 981 /* clip_box :: An optional clipping box. It is only used in */ 982 /* direct rendering mode. Note that coordinates here */ 983 /* should be expressed in _integer_ pixels (and not in */ 984 /* 26.6 fixed-point units). */ 985 /* */ 986 /* <Note> */ 987 /* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA */ 988 /* bit flag is set in the `flags' field, otherwise a monochrome */ 989 /* bitmap is generated. */ 990 /* */ 991 /* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */ 992 /* raster will call the `gray_spans' callback to draw gray pixel */ 993 /* spans. This allows direct composition over a pre-existing bitmap */ 994 /* through user-provided callbacks to perform the span drawing and */ 995 /* composition. Not supported by the monochrome rasterizer. */ 996 /* */ 997 typedef struct FT_Raster_Params_ 998 { 999 const FT_Bitmap* target; 1000 const void* source; 1001 int flags; 1002 FT_SpanFunc gray_spans; 1003 FT_SpanFunc black_spans; /* unused */ 1004 FT_Raster_BitTest_Func bit_test; /* unused */ 1005 FT_Raster_BitSet_Func bit_set; /* unused */ 1006 void* user; 1007 FT_BBox clip_box; 1008 1009 } FT_Raster_Params; 1010 1011 1012 /*************************************************************************/ 1013 /* */ 1014 /* <FuncType> */ 1015 /* FT_Raster_NewFunc */ 1016 /* */ 1017 /* <Description> */ 1018 /* A function used to create a new raster object. */ 1019 /* */ 1020 /* <Input> */ 1021 /* memory :: A handle to the memory allocator. */ 1022 /* */ 1023 /* <Output> */ 1024 /* raster :: A handle to the new raster object. */ 1025 /* */ 1026 /* <Return> */ 1027 /* Error code. 0~means success. */ 1028 /* */ 1029 /* <Note> */ 1030 /* The `memory' parameter is a typeless pointer in order to avoid */ 1031 /* un-wanted dependencies on the rest of the FreeType code. In */ 1032 /* practice, it is an @FT_Memory object, i.e., a handle to the */ 1033 /* standard FreeType memory allocator. However, this field can be */ 1034 /* completely ignored by a given raster implementation. */ 1035 /* */ 1036 typedef int 1037 (*FT_Raster_NewFunc)( void* memory, 1038 FT_Raster* raster ); 1039 1040 #define FT_Raster_New_Func FT_Raster_NewFunc 1041 1042 1043 /*************************************************************************/ 1044 /* */ 1045 /* <FuncType> */ 1046 /* FT_Raster_DoneFunc */ 1047 /* */ 1048 /* <Description> */ 1049 /* A function used to destroy a given raster object. */ 1050 /* */ 1051 /* <Input> */ 1052 /* raster :: A handle to the raster object. */ 1053 /* */ 1054 typedef void 1055 (*FT_Raster_DoneFunc)( FT_Raster raster ); 1056 1057 #define FT_Raster_Done_Func FT_Raster_DoneFunc 1058 1059 1060 /*************************************************************************/ 1061 /* */ 1062 /* <FuncType> */ 1063 /* FT_Raster_ResetFunc */ 1064 /* */ 1065 /* <Description> */ 1066 /* FreeType used to provide an area of memory called the `render */ 1067 /* pool' available to all registered rasterizers. This was not */ 1068 /* thread safe, however, and now FreeType never allocates this pool. */ 1069 /* */ 1070 /* This function is called after a new raster object is created. */ 1071 /* */ 1072 /* <Input> */ 1073 /* raster :: A handle to the new raster object. */ 1074 /* */ 1075 /* pool_base :: Previously, the address in memory of the render pool. */ 1076 /* Set this to NULL. */ 1077 /* */ 1078 /* pool_size :: Previously, the size in bytes of the render pool. */ 1079 /* Set this to 0. */ 1080 /* */ 1081 /* <Note> */ 1082 /* Rasterizers should rely on dynamic or stack allocation if they */ 1083 /* want to (a handle to the memory allocator is passed to the */ 1084 /* rasterizer constructor). */ 1085 /* */ 1086 typedef void 1087 (*FT_Raster_ResetFunc)( FT_Raster raster, 1088 unsigned char* pool_base, 1089 unsigned long pool_size ); 1090 1091 #define FT_Raster_Reset_Func FT_Raster_ResetFunc 1092 1093 1094 /*************************************************************************/ 1095 /* */ 1096 /* <FuncType> */ 1097 /* FT_Raster_SetModeFunc */ 1098 /* */ 1099 /* <Description> */ 1100 /* This function is a generic facility to change modes or attributes */ 1101 /* in a given raster. This can be used for debugging purposes, or */ 1102 /* simply to allow implementation-specific `features' in a given */ 1103 /* raster module. */ 1104 /* */ 1105 /* <Input> */ 1106 /* raster :: A handle to the new raster object. */ 1107 /* */ 1108 /* mode :: A 4-byte tag used to name the mode or property. */ 1109 /* */ 1110 /* args :: A pointer to the new mode/property to use. */ 1111 /* */ 1112 typedef int 1113 (*FT_Raster_SetModeFunc)( FT_Raster raster, 1114 unsigned long mode, 1115 void* args ); 1116 1117 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc 1118 1119 1120 /*************************************************************************/ 1121 /* */ 1122 /* <FuncType> */ 1123 /* FT_Raster_RenderFunc */ 1124 /* */ 1125 /* <Description> */ 1126 /* Invoke a given raster to scan-convert a given glyph image into a */ 1127 /* target bitmap. */ 1128 /* */ 1129 /* <Input> */ 1130 /* raster :: A handle to the raster object. */ 1131 /* */ 1132 /* params :: A pointer to an @FT_Raster_Params structure used to */ 1133 /* store the rendering parameters. */ 1134 /* */ 1135 /* <Return> */ 1136 /* Error code. 0~means success. */ 1137 /* */ 1138 /* <Note> */ 1139 /* The exact format of the source image depends on the raster's glyph */ 1140 /* format defined in its @FT_Raster_Funcs structure. It can be an */ 1141 /* @FT_Outline or anything else in order to support a large array of */ 1142 /* glyph formats. */ 1143 /* */ 1144 /* Note also that the render function can fail and return a */ 1145 /* `FT_Err_Unimplemented_Feature' error code if the raster used does */ 1146 /* not support direct composition. */ 1147 /* */ 1148 /* XXX: For now, the standard raster doesn't support direct */ 1149 /* composition but this should change for the final release (see */ 1150 /* the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c' */ 1151 /* for examples of distinct implementations that support direct */ 1152 /* composition). */ 1153 /* */ 1154 typedef int 1155 (*FT_Raster_RenderFunc)( FT_Raster raster, 1156 const FT_Raster_Params* params ); 1157 1158 #define FT_Raster_Render_Func FT_Raster_RenderFunc 1159 1160 1161 /*************************************************************************/ 1162 /* */ 1163 /* <Struct> */ 1164 /* FT_Raster_Funcs */ 1165 /* */ 1166 /* <Description> */ 1167 /* A structure used to describe a given raster class to the library. */ 1168 /* */ 1169 /* <Fields> */ 1170 /* glyph_format :: The supported glyph format for this raster. */ 1171 /* */ 1172 /* raster_new :: The raster constructor. */ 1173 /* */ 1174 /* raster_reset :: Used to reset the render pool within the raster. */ 1175 /* */ 1176 /* raster_render :: A function to render a glyph into a given bitmap. */ 1177 /* */ 1178 /* raster_done :: The raster destructor. */ 1179 /* */ 1180 typedef struct FT_Raster_Funcs_ 1181 { 1182 FT_Glyph_Format glyph_format; 1183 1184 FT_Raster_NewFunc raster_new; 1185 FT_Raster_ResetFunc raster_reset; 1186 FT_Raster_SetModeFunc raster_set_mode; 1187 FT_Raster_RenderFunc raster_render; 1188 FT_Raster_DoneFunc raster_done; 1189 1190 } FT_Raster_Funcs; 1191 1192 /* */ 1193 1194 1195 FT_END_HEADER 1196 1197 #endif /* FTIMAGE_H_ */ 1198 1199 | 1 /**************************************************************************** 2 * 3 * ftimage.h 4 * 5 * FreeType glyph image formats and default raster interface 6 * (specification). 7 * 8 * Copyright (C) 1996-2019 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 on 55 * the context, these can represent distances in integer font units, or 56 * 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 the 68 * FT_Pos type. 69 * 70 * @fields: 71 * x :: 72 * The horizontal coordinate. 73 * y :: 74 * The vertical coordinate. 75 */ 76 typedef struct FT_Vector_ 77 { 78 FT_Pos x; 79 FT_Pos y; 80 81 } FT_Vector; 82 83 84 /************************************************************************** 85 * 86 * @struct: 87 * FT_BBox 88 * 89 * @description: 90 * A structure used to hold an outline's bounding box, i.e., the 91 * coordinates of its extrema in the horizontal and vertical directions. 92 * 93 * @fields: 94 * xMin :: 95 * The horizontal minimum (left-most). 96 * 97 * yMin :: 98 * The vertical minimum (bottom-most). 99 * 100 * xMax :: 101 * The horizontal maximum (right-most). 102 * 103 * yMax :: 104 * The vertical maximum (top-most). 105 * 106 * @note: 107 * The bounding box is specified with the coordinates of the lower left 108 * and the upper right corner. In PostScript, those values are often 109 * called (llx,lly) and (urx,ury), respectively. 110 * 111 * If `yMin` is negative, this value gives the glyph's descender. 112 * Otherwise, the glyph doesn't descend below the baseline. Similarly, 113 * if `ymax` is positive, this value gives the glyph's ascender. 114 * 115 * `xMin` gives the horizontal distance from the glyph's origin to the 116 * left edge of the glyph's bounding box. If `xMin` is negative, the 117 * glyph extends to the left of the origin. 118 */ 119 typedef struct FT_BBox_ 120 { 121 FT_Pos xMin, yMin; 122 FT_Pos xMax, yMax; 123 124 } FT_BBox; 125 126 127 /************************************************************************** 128 * 129 * @enum: 130 * FT_Pixel_Mode 131 * 132 * @description: 133 * An enumeration type used to describe the format of pixels in a given 134 * bitmap. Note that additional formats may be added in the future. 135 * 136 * @values: 137 * FT_PIXEL_MODE_NONE :: 138 * Value~0 is reserved. 139 * 140 * FT_PIXEL_MODE_MONO :: 141 * A monochrome bitmap, using 1~bit per pixel. Note that pixels are 142 * stored in most-significant order (MSB), which means that the 143 * left-most pixel in a byte has value 128. 144 * 145 * FT_PIXEL_MODE_GRAY :: 146 * An 8-bit bitmap, generally used to represent anti-aliased glyph 147 * images. Each pixel is stored in one byte. Note that the number of 148 * 'gray' levels is stored in the `num_grays` field of the @FT_Bitmap 149 * structure (it generally is 256). 150 * 151 * FT_PIXEL_MODE_GRAY2 :: 152 * A 2-bit per pixel bitmap, used to represent embedded anti-aliased 153 * bitmaps in font files according to the OpenType specification. We 154 * haven't found a single font using this format, however. 155 * 156 * FT_PIXEL_MODE_GRAY4 :: 157 * A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps 158 * in font files according to the OpenType specification. We haven't 159 * found a single font using this format, however. 160 * 161 * FT_PIXEL_MODE_LCD :: 162 * An 8-bit bitmap, representing RGB or BGR decimated glyph images used 163 * for display on LCD displays; the bitmap is three times wider than 164 * the original glyph image. See also @FT_RENDER_MODE_LCD. 165 * 166 * FT_PIXEL_MODE_LCD_V :: 167 * An 8-bit bitmap, representing RGB or BGR decimated glyph images used 168 * for display on rotated LCD displays; the bitmap is three times 169 * taller than the original glyph image. See also 170 * @FT_RENDER_MODE_LCD_V. 171 * 172 * FT_PIXEL_MODE_BGRA :: 173 * [Since 2.5] An image with four 8-bit channels per pixel, 174 * representing a color image (such as emoticons) with alpha channel. 175 * For each pixel, the format is BGRA, which means, the blue channel 176 * comes first in memory. The color channels are pre-multiplied and in 177 * the sRGB colorspace. For example, full red at half-translucent 178 * opacity will be represented as '00,00,80,80', not '00,00,FF,80'. 179 * See also @FT_LOAD_COLOR. 180 */ 181 typedef enum FT_Pixel_Mode_ 182 { 183 FT_PIXEL_MODE_NONE = 0, 184 FT_PIXEL_MODE_MONO, 185 FT_PIXEL_MODE_GRAY, 186 FT_PIXEL_MODE_GRAY2, 187 FT_PIXEL_MODE_GRAY4, 188 FT_PIXEL_MODE_LCD, 189 FT_PIXEL_MODE_LCD_V, 190 FT_PIXEL_MODE_BGRA, 191 192 FT_PIXEL_MODE_MAX /* do not remove */ 193 194 } FT_Pixel_Mode; 195 196 197 /* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */ 198 /* values instead. */ 199 #define ft_pixel_mode_none FT_PIXEL_MODE_NONE 200 #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO 201 #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY 202 #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2 203 #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4 204 205 206 /************************************************************************** 207 * 208 * @struct: 209 * FT_Bitmap 210 * 211 * @description: 212 * A structure used to describe a bitmap or pixmap to the raster. Note 213 * that we now manage pixmaps of various depths through the `pixel_mode` 214 * field. 215 * 216 * @fields: 217 * rows :: 218 * The number of bitmap rows. 219 * 220 * width :: 221 * The number of pixels in bitmap row. 222 * 223 * pitch :: 224 * The pitch's absolute value is the number of bytes taken by one 225 * bitmap row, including padding. However, the pitch is positive when 226 * the bitmap has a 'down' flow, and negative when it has an 'up' flow. 227 * In all cases, the pitch is an offset to add to a bitmap pointer in 228 * order to go down one row. 229 * 230 * Note that 'padding' means the alignment of a bitmap to a byte 231 * border, and FreeType functions normally align to the smallest 232 * possible integer value. 233 * 234 * For the B/W rasterizer, `pitch` is always an even number. 235 * 236 * To change the pitch of a bitmap (say, to make it a multiple of 4), 237 * use @FT_Bitmap_Convert. Alternatively, you might use callback 238 * functions to directly render to the application's surface; see the 239 * file `example2.cpp` in the tutorial for a demonstration. 240 * 241 * buffer :: 242 * A typeless pointer to the bitmap buffer. This value should be 243 * aligned on 32-bit boundaries in most cases. 244 * 245 * num_grays :: 246 * This field is only used with @FT_PIXEL_MODE_GRAY; it gives the 247 * number of gray levels used in the bitmap. 248 * 249 * pixel_mode :: 250 * The pixel mode, i.e., how pixel bits are stored. See @FT_Pixel_Mode 251 * for possible values. 252 * 253 * palette_mode :: 254 * This field is intended for paletted pixel modes; it indicates how 255 * the palette is stored. Not used currently. 256 * 257 * palette :: 258 * A typeless pointer to the bitmap palette; this field is intended for 259 * paletted pixel modes. Not 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 :: 294 * The number of contours in the outline. 295 * 296 * n_points :: 297 * The number of points in the outline. 298 * 299 * points :: 300 * A pointer to an array of `n_points` @FT_Vector elements, giving the 301 * outline's point coordinates. 302 * 303 * tags :: 304 * A pointer to an array of `n_points` chars, giving each outline 305 * point's type. 306 * 307 * If bit~0 is unset, the point is 'off' the curve, i.e., a Bezier 308 * control point, while it is 'on' if set. 309 * 310 * Bit~1 is meaningful for 'off' points only. If set, it indicates a 311 * third-order Bezier arc control point; and a second-order control 312 * point if unset. 313 * 314 * If bit~2 is set, bits 5-7 contain the drop-out mode (as defined in 315 * the OpenType specification; the value is the same as the argument to 316 * the 'SCANMODE' instruction). 317 * 318 * Bits 3 and~4 are reserved for internal purposes. 319 * 320 * contours :: 321 * An array of `n_contours` shorts, giving the end point of each 322 * contour within the outline. For example, the first contour is 323 * defined by the points '0' to `contours[0]`, the second one is 324 * defined by the points `contours[0]+1` to `contours[1]`, etc. 325 * 326 * flags :: 327 * A set of bit flags used to characterize the outline and give hints 328 * to the scan-converter and hinter on how to convert/grid-fit it. See 329 * @FT_OUTLINE_XXX. 330 * 331 * @note: 332 * The B/W rasterizer only checks bit~2 in the `tags` array for the first 333 * point of each contour. The drop-out mode as given with 334 * @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and 335 * @FT_OUTLINE_INCLUDE_STUBS in `flags` is then overridden. 336 */ 337 typedef struct FT_Outline_ 338 { 339 short n_contours; /* number of contours in glyph */ 340 short n_points; /* number of points in the glyph */ 341 342 FT_Vector* points; /* the outline's points */ 343 char* tags; /* the points flags */ 344 short* contours; /* the contour end points */ 345 346 int flags; /* outline masks */ 347 348 } FT_Outline; 349 350 /* */ 351 352 /* Following limits must be consistent with */ 353 /* FT_Outline.{n_contours,n_points} */ 354 #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX 355 #define FT_OUTLINE_POINTS_MAX SHRT_MAX 356 357 358 /************************************************************************** 359 * 360 * @enum: 361 * FT_OUTLINE_XXX 362 * 363 * @description: 364 * A list of bit-field constants used for the flags in an outline's 365 * `flags` field. 366 * 367 * @values: 368 * FT_OUTLINE_NONE :: 369 * Value~0 is reserved. 370 * 371 * FT_OUTLINE_OWNER :: 372 * If set, this flag indicates that the outline's field arrays (i.e., 373 * `points`, `flags`, and `contours`) are 'owned' by the outline 374 * object, and should thus be freed when it is destroyed. 375 * 376 * FT_OUTLINE_EVEN_ODD_FILL :: 377 * By default, outlines are filled using the non-zero winding rule. If 378 * set to 1, the outline will be filled using the even-odd fill rule 379 * (only works with the smooth rasterizer). 380 * 381 * FT_OUTLINE_REVERSE_FILL :: 382 * By default, outside contours of an outline are oriented in 383 * clock-wise direction, as defined in the TrueType specification. 384 * This flag is set if the outline uses the opposite direction 385 * (typically for Type~1 fonts). This flag is ignored by the scan 386 * converter. 387 * 388 * FT_OUTLINE_IGNORE_DROPOUTS :: 389 * By default, the scan converter will try to detect drop-outs in an 390 * outline and correct the glyph bitmap to ensure consistent shape 391 * continuity. If set, this flag hints the scan-line converter to 392 * ignore such cases. See below for more information. 393 * 394 * FT_OUTLINE_SMART_DROPOUTS :: 395 * Select smart dropout control. If unset, use simple dropout control. 396 * Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more 397 * information. 398 * 399 * FT_OUTLINE_INCLUDE_STUBS :: 400 * If set, turn pixels on for 'stubs', otherwise exclude them. Ignored 401 * if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more 402 * information. 403 * 404 * FT_OUTLINE_HIGH_PRECISION :: 405 * This flag indicates that the scan-line converter should try to 406 * convert this outline to bitmaps with the highest possible quality. 407 * It is typically set for small character sizes. Note that this is 408 * only a hint that might be completely ignored by a given 409 * scan-converter. 410 * 411 * FT_OUTLINE_SINGLE_PASS :: 412 * This flag is set to force a given scan-converter to only use a 413 * single pass over the outline to render a bitmap glyph image. 414 * Normally, it is set for very large character sizes. It is only a 415 * hint that might be completely ignored by a given scan-converter. 416 * 417 * @note: 418 * The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and 419 * @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth rasterizer. 420 * 421 * There exists a second mechanism to pass the drop-out mode to the B/W 422 * rasterizer; see the `tags` field in @FT_Outline. 423 * 424 * Please refer to the description of the 'SCANTYPE' instruction in the 425 * OpenType specification (in file `ttinst1.doc`) how simple drop-outs, 426 * smart drop-outs, and stubs are defined. 427 */ 428 #define FT_OUTLINE_NONE 0x0 429 #define FT_OUTLINE_OWNER 0x1 430 #define FT_OUTLINE_EVEN_ODD_FILL 0x2 431 #define FT_OUTLINE_REVERSE_FILL 0x4 432 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8 433 #define FT_OUTLINE_SMART_DROPOUTS 0x10 434 #define FT_OUTLINE_INCLUDE_STUBS 0x20 435 436 #define FT_OUTLINE_HIGH_PRECISION 0x100 437 #define FT_OUTLINE_SINGLE_PASS 0x200 438 439 440 /* these constants are deprecated; use the corresponding */ 441 /* `FT_OUTLINE_XXX` values instead */ 442 #define ft_outline_none FT_OUTLINE_NONE 443 #define ft_outline_owner FT_OUTLINE_OWNER 444 #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL 445 #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL 446 #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS 447 #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION 448 #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS 449 450 /* */ 451 452 #define FT_CURVE_TAG( flag ) ( flag & 0x03 ) 453 454 /* see the `tags` field in `FT_Outline` for a description of the values */ 455 #define FT_CURVE_TAG_ON 0x01 456 #define FT_CURVE_TAG_CONIC 0x00 457 #define FT_CURVE_TAG_CUBIC 0x02 458 459 #define FT_CURVE_TAG_HAS_SCANMODE 0x04 460 461 #define FT_CURVE_TAG_TOUCH_X 0x08 /* reserved for TrueType hinter */ 462 #define FT_CURVE_TAG_TOUCH_Y 0x10 /* reserved for TrueType hinter */ 463 464 #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \ 465 FT_CURVE_TAG_TOUCH_Y ) 466 /* values 0x20, 0x40, and 0x80 are reserved */ 467 468 469 /* these constants are deprecated; use the corresponding */ 470 /* `FT_CURVE_TAG_XXX` values instead */ 471 #define FT_Curve_Tag_On FT_CURVE_TAG_ON 472 #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC 473 #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC 474 #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X 475 #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y 476 477 478 /************************************************************************** 479 * 480 * @functype: 481 * FT_Outline_MoveToFunc 482 * 483 * @description: 484 * A function pointer type used to describe the signature of a 'move to' 485 * function during outline walking/decomposition. 486 * 487 * A 'move to' is emitted to start a new contour in an outline. 488 * 489 * @input: 490 * to :: 491 * A pointer to the target point of the 'move to'. 492 * 493 * user :: 494 * A typeless pointer, which is passed from the caller of the 495 * decomposition function. 496 * 497 * @return: 498 * Error code. 0~means success. 499 */ 500 typedef int 501 (*FT_Outline_MoveToFunc)( const FT_Vector* to, 502 void* user ); 503 504 #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc 505 506 507 /************************************************************************** 508 * 509 * @functype: 510 * FT_Outline_LineToFunc 511 * 512 * @description: 513 * A function pointer type used to describe the signature of a 'line to' 514 * function during outline walking/decomposition. 515 * 516 * A 'line to' is emitted to indicate a segment in the outline. 517 * 518 * @input: 519 * to :: 520 * A pointer to the target point of the 'line to'. 521 * 522 * user :: 523 * A typeless pointer, which is passed from the caller of the 524 * decomposition function. 525 * 526 * @return: 527 * Error code. 0~means success. 528 */ 529 typedef int 530 (*FT_Outline_LineToFunc)( const FT_Vector* to, 531 void* user ); 532 533 #define FT_Outline_LineTo_Func FT_Outline_LineToFunc 534 535 536 /************************************************************************** 537 * 538 * @functype: 539 * FT_Outline_ConicToFunc 540 * 541 * @description: 542 * A function pointer type used to describe the signature of a 'conic to' 543 * function during outline walking or decomposition. 544 * 545 * A 'conic to' is emitted to indicate a second-order Bezier arc in the 546 * outline. 547 * 548 * @input: 549 * control :: 550 * An intermediate control point between the last position and the new 551 * target in `to`. 552 * 553 * to :: 554 * A pointer to the target end point of the conic arc. 555 * 556 * user :: 557 * A typeless pointer, which is passed from the caller of the 558 * decomposition function. 559 * 560 * @return: 561 * Error code. 0~means success. 562 */ 563 typedef int 564 (*FT_Outline_ConicToFunc)( const FT_Vector* control, 565 const FT_Vector* to, 566 void* user ); 567 568 #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc 569 570 571 /************************************************************************** 572 * 573 * @functype: 574 * FT_Outline_CubicToFunc 575 * 576 * @description: 577 * A function pointer type used to describe the signature of a 'cubic to' 578 * function during outline walking or decomposition. 579 * 580 * A 'cubic to' is emitted to indicate a third-order Bezier arc. 581 * 582 * @input: 583 * control1 :: 584 * A pointer to the first Bezier control point. 585 * 586 * control2 :: 587 * A pointer to the second Bezier control point. 588 * 589 * to :: 590 * A pointer to the target end point. 591 * 592 * user :: 593 * A typeless pointer, which is passed from the caller of the 594 * decomposition function. 595 * 596 * @return: 597 * Error code. 0~means success. 598 */ 599 typedef int 600 (*FT_Outline_CubicToFunc)( const FT_Vector* control1, 601 const FT_Vector* control2, 602 const FT_Vector* to, 603 void* user ); 604 605 #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc 606 607 608 /************************************************************************** 609 * 610 * @struct: 611 * FT_Outline_Funcs 612 * 613 * @description: 614 * A structure to hold various function pointers used during outline 615 * decomposition in order to emit segments, conic, and cubic Beziers. 616 * 617 * @fields: 618 * move_to :: 619 * The 'move to' emitter. 620 * 621 * line_to :: 622 * The segment emitter. 623 * 624 * conic_to :: 625 * The second-order Bezier arc emitter. 626 * 627 * cubic_to :: 628 * The third-order Bezier arc emitter. 629 * 630 * shift :: 631 * The shift that is applied to coordinates before they are sent to the 632 * emitter. 633 * 634 * delta :: 635 * The delta that is applied to coordinates before they are sent to the 636 * emitter, but after the shift. 637 * 638 * @note: 639 * The point coordinates sent to the emitters are the transformed version 640 * of the original coordinates (this is important for high accuracy 641 * during scan-conversion). The transformation is simple: 642 * 643 * ``` 644 * x' = (x << shift) - delta 645 * y' = (y << shift) - delta 646 * ``` 647 * 648 * Set the values of `shift` and `delta` to~0 to get the original point 649 * coordinates. 650 */ 651 typedef struct FT_Outline_Funcs_ 652 { 653 FT_Outline_MoveToFunc move_to; 654 FT_Outline_LineToFunc line_to; 655 FT_Outline_ConicToFunc conic_to; 656 FT_Outline_CubicToFunc cubic_to; 657 658 int shift; 659 FT_Pos delta; 660 661 } FT_Outline_Funcs; 662 663 664 /************************************************************************** 665 * 666 * @section: 667 * basic_types 668 * 669 */ 670 671 672 /************************************************************************** 673 * 674 * @macro: 675 * FT_IMAGE_TAG 676 * 677 * @description: 678 * This macro converts four-letter tags to an unsigned long type. 679 * 680 * @note: 681 * Since many 16-bit compilers don't like 32-bit enumerations, you should 682 * redefine this macro in case of problems to something like this: 683 * 684 * ``` 685 * #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value 686 * ``` 687 * 688 * to get a simple enumeration without assigning special numbers. 689 */ 690 #ifndef FT_IMAGE_TAG 691 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \ 692 value = ( ( (unsigned long)_x1 << 24 ) | \ 693 ( (unsigned long)_x2 << 16 ) | \ 694 ( (unsigned long)_x3 << 8 ) | \ 695 (unsigned long)_x4 ) 696 #endif /* FT_IMAGE_TAG */ 697 698 699 /************************************************************************** 700 * 701 * @enum: 702 * FT_Glyph_Format 703 * 704 * @description: 705 * An enumeration type used to describe the format of a given glyph 706 * image. Note that this version of FreeType only supports two image 707 * formats, even though future font drivers will be able to register 708 * their own format. 709 * 710 * @values: 711 * FT_GLYPH_FORMAT_NONE :: 712 * The value~0 is reserved. 713 * 714 * FT_GLYPH_FORMAT_COMPOSITE :: 715 * The glyph image is a composite of several other images. This format 716 * is _only_ used with @FT_LOAD_NO_RECURSE, and is used to report 717 * compound glyphs (like accented characters). 718 * 719 * FT_GLYPH_FORMAT_BITMAP :: 720 * The glyph image is a bitmap, and can be described as an @FT_Bitmap. 721 * You generally need to access the `bitmap` field of the 722 * @FT_GlyphSlotRec structure to read it. 723 * 724 * FT_GLYPH_FORMAT_OUTLINE :: 725 * The glyph image is a vectorial outline made of line segments and 726 * Bezier arcs; it can be described as an @FT_Outline; you generally 727 * want to access the `outline` field of the @FT_GlyphSlotRec structure 728 * to read it. 729 * 730 * FT_GLYPH_FORMAT_PLOTTER :: 731 * The glyph image is a vectorial path with no inside and outside 732 * contours. Some Type~1 fonts, like those in the Hershey family, 733 * contain glyphs in this format. These are described as @FT_Outline, 734 * but FreeType isn't currently capable of rendering them correctly. 735 */ 736 typedef enum FT_Glyph_Format_ 737 { 738 FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ), 739 740 FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ), 741 FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ), 742 FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ), 743 FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' ) 744 745 } FT_Glyph_Format; 746 747 748 /* these constants are deprecated; use the corresponding */ 749 /* `FT_Glyph_Format` values instead. */ 750 #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE 751 #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE 752 #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP 753 #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE 754 #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER 755 756 757 /*************************************************************************/ 758 /*************************************************************************/ 759 /*************************************************************************/ 760 /***** *****/ 761 /***** R A S T E R D E F I N I T I O N S *****/ 762 /***** *****/ 763 /*************************************************************************/ 764 /*************************************************************************/ 765 /*************************************************************************/ 766 767 768 /************************************************************************** 769 * 770 * A raster is a scan converter, in charge of rendering an outline into a 771 * bitmap. This section contains the public API for rasters. 772 * 773 * Note that in FreeType 2, all rasters are now encapsulated within 774 * specific modules called 'renderers'. See `ftrender.h` for more details 775 * on renderers. 776 * 777 */ 778 779 780 /************************************************************************** 781 * 782 * @section: 783 * raster 784 * 785 * @title: 786 * Scanline Converter 787 * 788 * @abstract: 789 * How vectorial outlines are converted into bitmaps and pixmaps. 790 * 791 * @description: 792 * This section contains technical definitions. 793 * 794 * @order: 795 * FT_Raster 796 * FT_Span 797 * FT_SpanFunc 798 * 799 * FT_Raster_Params 800 * FT_RASTER_FLAG_XXX 801 * 802 * FT_Raster_NewFunc 803 * FT_Raster_DoneFunc 804 * FT_Raster_ResetFunc 805 * FT_Raster_SetModeFunc 806 * FT_Raster_RenderFunc 807 * FT_Raster_Funcs 808 * 809 */ 810 811 812 /************************************************************************** 813 * 814 * @type: 815 * FT_Raster 816 * 817 * @description: 818 * An opaque handle (pointer) to a raster object. Each object can be 819 * used independently to convert an outline into a bitmap or pixmap. 820 */ 821 typedef struct FT_RasterRec_* FT_Raster; 822 823 824 /************************************************************************** 825 * 826 * @struct: 827 * FT_Span 828 * 829 * @description: 830 * A structure used to model a single span of gray pixels when rendering 831 * an anti-aliased bitmap. 832 * 833 * @fields: 834 * x :: 835 * The span's horizontal start position. 836 * 837 * len :: 838 * The span's length in pixels. 839 * 840 * coverage :: 841 * The span color/coverage, ranging from 0 (background) to 255 842 * (foreground). 843 * 844 * @note: 845 * This structure is used by the span drawing callback type named 846 * @FT_SpanFunc that takes the y~coordinate of the span as a parameter. 847 * 848 * The coverage value is always between 0 and 255. If you want less gray 849 * values, the callback function has to reduce them. 850 */ 851 typedef struct FT_Span_ 852 { 853 short x; 854 unsigned short len; 855 unsigned char coverage; 856 857 } FT_Span; 858 859 860 /************************************************************************** 861 * 862 * @functype: 863 * FT_SpanFunc 864 * 865 * @description: 866 * A function used as a call-back by the anti-aliased renderer in order 867 * to let client applications draw themselves the gray pixel spans on 868 * each scan line. 869 * 870 * @input: 871 * y :: 872 * The scanline's y~coordinate. 873 * 874 * count :: 875 * The number of spans to draw on this scanline. 876 * 877 * spans :: 878 * A table of `count` spans to draw on the scanline. 879 * 880 * user :: 881 * User-supplied data that is passed to the callback. 882 * 883 * @note: 884 * This callback allows client applications to directly render the gray 885 * spans of the anti-aliased bitmap to any kind of surfaces. 886 * 887 * This can be used to write anti-aliased outlines directly to a given 888 * background bitmap, and even perform translucency. 889 */ 890 typedef void 891 (*FT_SpanFunc)( int y, 892 int count, 893 const FT_Span* spans, 894 void* user ); 895 896 #define FT_Raster_Span_Func FT_SpanFunc 897 898 899 /************************************************************************** 900 * 901 * @functype: 902 * FT_Raster_BitTest_Func 903 * 904 * @description: 905 * Deprecated, unimplemented. 906 */ 907 typedef int 908 (*FT_Raster_BitTest_Func)( int y, 909 int x, 910 void* user ); 911 912 913 /************************************************************************** 914 * 915 * @functype: 916 * FT_Raster_BitSet_Func 917 * 918 * @description: 919 * Deprecated, unimplemented. 920 */ 921 typedef void 922 (*FT_Raster_BitSet_Func)( int y, 923 int x, 924 void* user ); 925 926 927 /************************************************************************** 928 * 929 * @enum: 930 * FT_RASTER_FLAG_XXX 931 * 932 * @description: 933 * A list of bit flag constants as used in the `flags` field of a 934 * @FT_Raster_Params structure. 935 * 936 * @values: 937 * FT_RASTER_FLAG_DEFAULT :: 938 * This value is 0. 939 * 940 * FT_RASTER_FLAG_AA :: 941 * This flag is set to indicate that an anti-aliased glyph image should 942 * be generated. Otherwise, it will be monochrome (1-bit). 943 * 944 * FT_RASTER_FLAG_DIRECT :: 945 * This flag is set to indicate direct rendering. In this mode, client 946 * applications must provide their own span callback. This lets them 947 * directly draw or compose over an existing bitmap. If this bit is 948 * not set, the target pixmap's buffer _must_ be zeroed before 949 * rendering. 950 * 951 * Direct rendering is only possible with anti-aliased glyphs. 952 * 953 * FT_RASTER_FLAG_CLIP :: 954 * This flag is only used in direct rendering mode. If set, the output 955 * will be clipped to a box specified in the `clip_box` field of the 956 * @FT_Raster_Params structure. 957 * 958 * Note that by default, the glyph bitmap is clipped to the target 959 * pixmap, except in direct rendering mode where all spans are 960 * generated if no clipping box is set. 961 */ 962 #define FT_RASTER_FLAG_DEFAULT 0x0 963 #define FT_RASTER_FLAG_AA 0x1 964 #define FT_RASTER_FLAG_DIRECT 0x2 965 #define FT_RASTER_FLAG_CLIP 0x4 966 967 /* these constants are deprecated; use the corresponding */ 968 /* `FT_RASTER_FLAG_XXX` values instead */ 969 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT 970 #define ft_raster_flag_aa FT_RASTER_FLAG_AA 971 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT 972 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP 973 974 975 /************************************************************************** 976 * 977 * @struct: 978 * FT_Raster_Params 979 * 980 * @description: 981 * A structure to hold the arguments used by a raster's render function. 982 * 983 * @fields: 984 * target :: 985 * The target bitmap. 986 * 987 * source :: 988 * A pointer to the source glyph image (e.g., an @FT_Outline). 989 * 990 * flags :: 991 * The rendering flags. 992 * 993 * gray_spans :: 994 * The gray span drawing callback. 995 * 996 * black_spans :: 997 * Unused. 998 * 999 * bit_test :: 1000 * Unused. 1001 * 1002 * bit_set :: 1003 * Unused. 1004 * 1005 * user :: 1006 * User-supplied data that is passed to each drawing callback. 1007 * 1008 * clip_box :: 1009 * An optional clipping box. It is only used in direct rendering mode. 1010 * Note that coordinates here should be expressed in _integer_ pixels 1011 * (and not in 26.6 fixed-point units). 1012 * 1013 * @note: 1014 * An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA bit 1015 * flag is set in the `flags` field, otherwise a monochrome bitmap is 1016 * generated. 1017 * 1018 * If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags`, the raster 1019 * will call the `gray_spans` callback to draw gray pixel spans. This 1020 * allows direct composition over a pre-existing bitmap through 1021 * user-provided callbacks to perform the span drawing and composition. 1022 * Not supported by the monochrome rasterizer. 1023 */ 1024 typedef struct FT_Raster_Params_ 1025 { 1026 const FT_Bitmap* target; 1027 const void* source; 1028 int flags; 1029 FT_SpanFunc gray_spans; 1030 FT_SpanFunc black_spans; /* unused */ 1031 FT_Raster_BitTest_Func bit_test; /* unused */ 1032 FT_Raster_BitSet_Func bit_set; /* unused */ 1033 void* user; 1034 FT_BBox clip_box; 1035 1036 } FT_Raster_Params; 1037 1038 1039 /************************************************************************** 1040 * 1041 * @functype: 1042 * FT_Raster_NewFunc 1043 * 1044 * @description: 1045 * A function used to create a new raster object. 1046 * 1047 * @input: 1048 * memory :: 1049 * A handle to the memory allocator. 1050 * 1051 * @output: 1052 * raster :: 1053 * A handle to the new raster object. 1054 * 1055 * @return: 1056 * Error code. 0~means success. 1057 * 1058 * @note: 1059 * The `memory` parameter is a typeless pointer in order to avoid 1060 * un-wanted dependencies on the rest of the FreeType code. In practice, 1061 * it is an @FT_Memory object, i.e., a handle to the standard FreeType 1062 * memory allocator. However, this field can be completely ignored by a 1063 * given raster implementation. 1064 */ 1065 typedef int 1066 (*FT_Raster_NewFunc)( void* memory, 1067 FT_Raster* raster ); 1068 1069 #define FT_Raster_New_Func FT_Raster_NewFunc 1070 1071 1072 /************************************************************************** 1073 * 1074 * @functype: 1075 * FT_Raster_DoneFunc 1076 * 1077 * @description: 1078 * A function used to destroy a given raster object. 1079 * 1080 * @input: 1081 * raster :: 1082 * A handle to the raster object. 1083 */ 1084 typedef void 1085 (*FT_Raster_DoneFunc)( FT_Raster raster ); 1086 1087 #define FT_Raster_Done_Func FT_Raster_DoneFunc 1088 1089 1090 /************************************************************************** 1091 * 1092 * @functype: 1093 * FT_Raster_ResetFunc 1094 * 1095 * @description: 1096 * FreeType used to provide an area of memory called the 'render pool' 1097 * available to all registered rasterizers. This was not thread safe, 1098 * however, and now FreeType never allocates this pool. 1099 * 1100 * This function is called after a new raster object is created. 1101 * 1102 * @input: 1103 * raster :: 1104 * A handle to the new raster object. 1105 * 1106 * pool_base :: 1107 * Previously, the address in memory of the render pool. Set this to 1108 * `NULL`. 1109 * 1110 * pool_size :: 1111 * Previously, the size in bytes of the render pool. Set this to 0. 1112 * 1113 * @note: 1114 * Rasterizers should rely on dynamic or stack allocation if they want to 1115 * (a handle to the memory allocator is passed to the rasterizer 1116 * constructor). 1117 */ 1118 typedef void 1119 (*FT_Raster_ResetFunc)( FT_Raster raster, 1120 unsigned char* pool_base, 1121 unsigned long pool_size ); 1122 1123 #define FT_Raster_Reset_Func FT_Raster_ResetFunc 1124 1125 1126 /************************************************************************** 1127 * 1128 * @functype: 1129 * FT_Raster_SetModeFunc 1130 * 1131 * @description: 1132 * This function is a generic facility to change modes or attributes in a 1133 * given raster. This can be used for debugging purposes, or simply to 1134 * allow implementation-specific 'features' in a given raster module. 1135 * 1136 * @input: 1137 * raster :: 1138 * A handle to the new raster object. 1139 * 1140 * mode :: 1141 * A 4-byte tag used to name the mode or property. 1142 * 1143 * args :: 1144 * A pointer to the new mode/property to use. 1145 */ 1146 typedef int 1147 (*FT_Raster_SetModeFunc)( FT_Raster raster, 1148 unsigned long mode, 1149 void* args ); 1150 1151 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc 1152 1153 1154 /************************************************************************** 1155 * 1156 * @functype: 1157 * FT_Raster_RenderFunc 1158 * 1159 * @description: 1160 * Invoke a given raster to scan-convert a given glyph image into a 1161 * target bitmap. 1162 * 1163 * @input: 1164 * raster :: 1165 * A handle to the raster object. 1166 * 1167 * params :: 1168 * A pointer to an @FT_Raster_Params structure used to store the 1169 * rendering parameters. 1170 * 1171 * @return: 1172 * Error code. 0~means success. 1173 * 1174 * @note: 1175 * The exact format of the source image depends on the raster's glyph 1176 * format defined in its @FT_Raster_Funcs structure. It can be an 1177 * @FT_Outline or anything else in order to support a large array of 1178 * glyph formats. 1179 * 1180 * Note also that the render function can fail and return a 1181 * `FT_Err_Unimplemented_Feature` error code if the raster used does not 1182 * support direct composition. 1183 */ 1184 typedef int 1185 (*FT_Raster_RenderFunc)( FT_Raster raster, 1186 const FT_Raster_Params* params ); 1187 1188 #define FT_Raster_Render_Func FT_Raster_RenderFunc 1189 1190 1191 /************************************************************************** 1192 * 1193 * @struct: 1194 * FT_Raster_Funcs 1195 * 1196 * @description: 1197 * A structure used to describe a given raster class to the library. 1198 * 1199 * @fields: 1200 * glyph_format :: 1201 * The supported glyph format for this raster. 1202 * 1203 * raster_new :: 1204 * The raster constructor. 1205 * 1206 * raster_reset :: 1207 * Used to reset the render pool within the raster. 1208 * 1209 * raster_render :: 1210 * A function to render a glyph into a given bitmap. 1211 * 1212 * raster_done :: 1213 * The raster destructor. 1214 */ 1215 typedef struct FT_Raster_Funcs_ 1216 { 1217 FT_Glyph_Format glyph_format; 1218 1219 FT_Raster_NewFunc raster_new; 1220 FT_Raster_ResetFunc raster_reset; 1221 FT_Raster_SetModeFunc raster_set_mode; 1222 FT_Raster_RenderFunc raster_render; 1223 FT_Raster_DoneFunc raster_done; 1224 1225 } FT_Raster_Funcs; 1226 1227 /* */ 1228 1229 1230 FT_END_HEADER 1231 1232 #endif /* FTIMAGE_H_ */ 1233 1234 |