1#Topic Point 2#Alias Points ## 3#Alias Point_Reference ## 4 5#Struct SkPoint 6 7#Code 8#Populate 9## 10 11SkPoint holds two 32-bit floating point coordinates. 12 13#Member SkScalar fX 14#Line # x-axis value ## 15x-axis value used by both Point and Vector. May contain any value, including 16infinities and NaN. 17## 18 19#Member SkScalar fY 20#Line # y-axis value ## 21y-axis value used by both Point and Vector. May contain any value, including 22infinities and NaN. 23## 24 25# ------------------------------------------------------------------------------ 26 27#Method static constexpr SkPoint Make(SkScalar x, SkScalar y) 28#In Constructors 29#Line # constructs from SkScalar inputs ## 30#Populate 31 32#Example 33SkPoint pt1 = {45, 66}; 34SkPoint pt2 = SkPoint::Make(45, 66); 35SkVector v1 = {45, 66}; 36SkVector v2 = SkPoint::Make(45, 66); 37SkDebugf("all %s" "equal\n", pt1 == pt2 && pt2 == v1 && v1 == v2 ? "" : "not "); 38#StdOut 39all equal 40## 41## 42 43#SeeAlso set() iset() SkIPoint::Make 44 45#Method ## 46 47# ------------------------------------------------------------------------------ 48 49#Subtopic Property 50#Line # member values ## 51## 52 53#Method SkScalar x() const 54#In Property 55#Line # returns fX ## 56#Populate 57 58#Example 59SkPoint pt1 = {45, 66}; 60SkDebugf("pt1.fX %c= pt1.x()\n", pt1.fX == pt1.x() ? '=' : '!'); 61#StdOut 62pt1.fX == pt1.x() 63## 64## 65 66#SeeAlso y() SkIPoint::x() 67 68#Method ## 69 70# ------------------------------------------------------------------------------ 71 72#Method SkScalar y() const 73#In Property 74#Line # returns fY ## 75#Populate 76 77#Example 78SkPoint pt1 = {45, 66}; 79SkDebugf("pt1.fY %c= pt1.y()\n", pt1.fY == pt1.y() ? '=' : '!'); 80#StdOut 81pt1.fY == pt1.y() 82## 83## 84 85#SeeAlso x() SkIPoint::y() 86 87#Method ## 88 89# ------------------------------------------------------------------------------ 90 91#Method bool isZero() const 92#In Property 93#Line # returns true if both members equal zero ## 94#Populate 95 96#Example 97SkPoint pt = { 0.f, -0.f}; 98SkDebugf("pt.fX=%c%g pt.fY=%c%g\n", std::signbit(pt.fX) ? '-' : '+', fabsf(pt.fX), 99 std::signbit(pt.fY) ? '-' : '+', fabsf(pt.fY)); 100SkDebugf("pt.isZero() == %s\n", pt.isZero() ? "true" : "false"); 101#StdOut 102pt.fX=+0 pt.fY=-0 103pt.isZero() == true 104## 105## 106 107#SeeAlso isFinite SkIPoint::isZero 108 109#Method ## 110 111# ------------------------------------------------------------------------------ 112 113#Subtopic Set 114#Line # replaces all values ## 115## 116 117#Method void set(SkScalar x, SkScalar y) 118#In Set 119#Line # sets to SkScalar input ## 120#Populate 121 122#Example 123SkPoint pt1, pt2 = { SK_ScalarPI, SK_ScalarSqrt2 }; 124pt1.set(SK_ScalarPI, SK_ScalarSqrt2); 125SkDebugf("pt1 %c= pt2\n", pt1 == pt2 ? '=' : '!'); 126#StdOut 127pt1 == pt2 128## 129## 130 131#SeeAlso iset() Make 132 133#Method ## 134 135# ------------------------------------------------------------------------------ 136 137#Method void iset(int32_t x, int32_t y) 138#In Set 139#Line # sets to integer input ## 140#Populate 141 142#Example 143SkPoint pt1, pt2 = { SK_MinS16, SK_MaxS16 }; 144pt1.iset(SK_MinS16, SK_MaxS16); 145SkDebugf("pt1 %c= pt2\n", pt1 == pt2 ? '=' : '!'); 146## 147 148#SeeAlso set Make SkIPoint::set 149 150#Method ## 151 152# ------------------------------------------------------------------------------ 153 154#Method void iset(const SkIPoint& p) 155#Populate 156 157#Example 158SkIPoint iPt = { SK_MinS32, SK_MaxS32 }; 159SkPoint fPt; 160fPt.iset(iPt); 161SkDebugf("iPt: %d, %d\n", iPt.fX, iPt.fY); 162SkDebugf("fPt: %g, %g\n", fPt.fX, fPt.fY); 163#StdOut 164iPt: -2147483647, 2147483647 165fPt: -2.14748e+09, 2.14748e+09 166## 167## 168 169#SeeAlso set Make SkIPoint::set 170 171#Method ## 172 173# ------------------------------------------------------------------------------ 174 175#Method void setAbs(const SkPoint& pt) 176#In Set 177#Line # sets sign of both members to positive ## 178#Populate 179 180#Example 181SkPoint test[] = { {0.f, -0.f}, {-1, -2}, 182 { SK_ScalarInfinity, SK_ScalarNegativeInfinity }, 183 { SK_ScalarNaN, -SK_ScalarNaN } }; 184for (const SkPoint& pt : test) { 185 SkPoint absPt; 186 absPt.setAbs(pt); 187 SkDebugf("pt: %g, %g abs: %g, %g\n", pt.fX, pt.fY, absPt.fX, absPt.fY); 188} 189#StdOut 190pt: 0, -0 abs: 0, 0 191pt: -1, -2 abs: 1, 2 192pt: inf, -inf abs: inf, inf 193pt: nan, -nan abs: nan, nan 194## 195## 196 197#SeeAlso set Make negate 198 199#Method ## 200 201# ------------------------------------------------------------------------------ 202 203#Subtopic Offset 204#Line # moves sides ## 205## 206 207#Method static void Offset(SkPoint points[], int count, const SkVector& offset) 208#In Offset 209#Line # translates Point array ## 210#Populate 211 212#Example 213 SkPaint paint; 214 paint.setAntiAlias(true); 215 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 216 { 6, 4 }, { 7, 5 }, { 5, 7 }, 217 { 4, 6 }, { 3, 7 }, { 1, 5 }, 218 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 219 canvas->scale(30, 15); 220 paint.setStyle(SkPaint::kStroke_Style); 221 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 222 SkPoint::Offset(points, SK_ARRAY_COUNT(points), { 1, 9 } ); 223 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 224## 225 226#SeeAlso offset operator+=(const SkVector& v) 227 228#Method ## 229 230# ------------------------------------------------------------------------------ 231 232#Method static void Offset(SkPoint points[], int count, SkScalar dx, SkScalar dy) 233#Populate 234 235#Example 236 SkPaint paint; 237 paint.setAntiAlias(true); 238 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 239 { 6, 4 }, { 7, 5 }, { 5, 7 }, 240 { 4, 6 }, { 3, 7 }, { 1, 5 }, 241 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 242 canvas->scale(30, 15); 243 paint.setStyle(SkPaint::kStroke_Style); 244 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 245 SkPoint::Offset(points, SK_ARRAY_COUNT(points), 1, 9); 246 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 247## 248 249#SeeAlso offset operator+=(const SkVector& v) 250 251#Method ## 252 253# ------------------------------------------------------------------------------ 254 255#Method void offset(SkScalar dx, SkScalar dy) 256#In Offset 257#Line # translates Point ## 258#Populate 259 260#Example 261#Height 128 262 SkPaint paint; 263 paint.setAntiAlias(true); 264 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 265 { 6, 4 }, { 7, 5 }, { 5, 7 }, 266 { 4, 6 }, { 3, 7 }, { 1, 5 }, 267 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 268 canvas->scale(30, 15); 269 paint.setStyle(SkPaint::kStroke_Style); 270 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 271 points[1].offset(1, 1); 272 paint.setColor(SK_ColorRED); 273 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 274## 275 276#SeeAlso Offset operator+=(const SkVector& v) 277 278#Method ## 279 280# ------------------------------------------------------------------------------ 281 282#Method SkScalar length() const 283#In Property 284#Line # returns straight-line distance to origin ## 285#Populate 286 287#Example 288#Height 192 289 SkPaint paint; 290 paint.setAntiAlias(true); 291 const SkPoint points[] = { { 90, 30 }, { 120, 150 }, { 150, 30 }, { 210, 90 } }; 292 const SkPoint origin = {30, 140}; 293 for (auto point : points) { 294 canvas->drawLine(origin, point, paint); 295 SkAutoCanvasRestore acr(canvas, true); 296 SkScalar angle = SkScalarATan2((point.fY - origin.fY), point.fX - origin.fX); 297 canvas->rotate(angle * 180 / SK_ScalarPI, origin.fX, origin.fY); 298 SkString length("length = "); 299 length.appendScalar(point.length()); 300 canvas->drawString(length, origin.fX + 25, origin.fY - 4, paint); 301 } 302## 303 304#SeeAlso distanceToOrigin Length setLength Distance 305 306#Method ## 307 308# ------------------------------------------------------------------------------ 309 310#Method SkScalar distanceToOrigin() const 311#In Property 312#Line # returns straight-line distance to origin ## 313#Populate 314 315#Example 316#Height 192 317 SkPaint paint; 318 paint.setAntiAlias(true); 319 const SkPoint points[] = { { 60, -110 }, { 90, 10 }, { 120, -110 }, { 180, -50 } }; 320 const SkPoint origin = {0, 0}; 321 canvas->translate(30, 140); 322 for (auto point : points) { 323 canvas->drawLine(origin, point, paint); 324 SkAutoCanvasRestore acr(canvas, true); 325 SkScalar angle = SkScalarATan2((point.fY - origin.fY), point.fX - origin.fX); 326 canvas->rotate(angle * 180 / SK_ScalarPI, origin.fX, origin.fY); 327 SkString distance("distance = "); 328 distance.appendScalar(point.distanceToOrigin()); 329 canvas->drawString(distance, origin.fX + 25, origin.fY - 4, paint); 330 } 331## 332 333#SeeAlso length Length setLength Distance 334 335#Method ## 336 337# ------------------------------------------------------------------------------ 338 339#Method bool normalize() 340#In Set 341#Line # sets length to one, preserving direction ## 342#Populate 343 344#Example 345 SkPaint paint; 346 paint.setAntiAlias(true); 347 const SkPoint lines[][2] = { {{ 30, 110 }, { 190, 30 }}, 348 {{ 120, 140 }, { 30, 220 }}}; 349 for (auto line : lines) { 350 canvas->drawLine(line[0], line[1], paint); 351 SkVector vector = line[1] - line[0]; 352 if (vector.normalize()) { 353 SkVector rotate90 = { -vector.fY, vector.fX }; 354 rotate90 *= 10.f; 355 canvas->drawLine(line[0] - rotate90, line[0] + rotate90, paint); 356 canvas->drawLine(line[1] - rotate90, line[1] + rotate90, paint); 357 } 358 } 359## 360 361#SeeAlso Normalize setLength length Length 362 363#Method ## 364 365# ------------------------------------------------------------------------------ 366 367#Method bool setNormalize(SkScalar x, SkScalar y) 368#In Set 369#Line # sets length to one, in direction of (x, y) ## 370#Populate 371 372#Example 373 SkPaint paint; 374 paint.setAntiAlias(true); 375 const SkPoint points[] = { { 60, -110 }, { 90, 10 }, { 120, -110 }, { 180, -50 } }; 376 const SkPoint origin = {0, 0}; 377 canvas->translate(30, 140); 378 for (auto point : points) { 379 paint.setStrokeWidth(1); 380 paint.setColor(SK_ColorBLACK); 381 canvas->drawLine(origin, point, paint); 382 SkVector normal; 383 normal.setNormalize(point.fX, point.fY); 384 normal *= 100; 385 paint.setStrokeWidth(10); 386 paint.setColor(0x3f4512bf); 387 canvas->drawLine(origin, normal, paint); 388 } 389## 390 391#SeeAlso normalize setLength 392 393#Method ## 394 395# ------------------------------------------------------------------------------ 396 397#Method bool setLength(SkScalar length) 398#In Set 399#Line # sets straight-line distance to origin ## 400#Populate 401 402#Example 403#Height 160 404 SkPaint paint; 405 paint.setAntiAlias(true); 406 const SkPoint points[] = { { 60, -110 }, { 90, 10 }, { 120, -110 }, { 180, -50 } }; 407 const SkPoint origin = {0, 0}; 408 canvas->translate(30, 140); 409 for (auto point : points) { 410 paint.setStrokeWidth(1); 411 paint.setColor(SK_ColorBLACK); 412 canvas->drawLine(origin, point, paint); 413 SkVector normal = point; 414 normal.setLength(100); 415 paint.setStrokeWidth(10); 416 paint.setColor(0x3f45bf12); 417 canvas->drawLine(origin, normal, paint); 418 } 419## 420 421#SeeAlso length Length setNormalize setAbs 422 423#Method ## 424 425# ------------------------------------------------------------------------------ 426 427#Method bool setLength(SkScalar x, SkScalar y, SkScalar length) 428#Populate 429 430#Example 431#Height 160 432 SkPaint paint; 433 paint.setAntiAlias(true); 434 const SkPoint points[] = { { 60, -110 }, { 90, 10 }, { 120, -110 }, { 180, -50 } }; 435 const SkPoint origin = {0, 0}; 436 canvas->translate(30, 140); 437 for (auto point : points) { 438 paint.setStrokeWidth(1); 439 paint.setColor(SK_ColorBLACK); 440 canvas->drawLine(origin, point, paint); 441 SkVector normal; 442 normal.setLength(point.fX, point.fY, 100); 443 paint.setStrokeWidth(10); 444 paint.setColor(0x3fbf4512); 445 canvas->drawLine(origin, normal, paint); 446 } 447## 448 449#SeeAlso length Length setNormalize setAbs 450 451#Method ## 452 453# ------------------------------------------------------------------------------ 454 455#Method void scale(SkScalar scale, SkPoint* dst) const 456#In Offset 457#In Operators 458#Line # multiplies Point by scale factor ## 459#Populate 460 461#Example 462 SkPaint paint; 463 paint.setAntiAlias(true); 464 SkPoint point = {40, -15}, scaled; 465 SkPoint origin = {30, 110}; 466 for (auto scale : {1, 2, 3, 5}) { 467 paint.setStrokeWidth(scale * 5); 468 paint.setARGB(0x7f, 0x9f, 0xbf, 0x33 * scale); 469 point.scale(scale, &scaled); 470 canvas->drawLine(origin, origin + scaled, paint); 471 } 472## 473 474#SeeAlso operator*(SkScalar scale) const operator*=(SkScalar scale) setLength 475 476#Method ## 477 478# ------------------------------------------------------------------------------ 479 480#Method void scale(SkScalar value) 481#Populate 482 483#Example 484 SkPaint paint; 485 paint.setAntiAlias(true); 486 SkPoint point = {40, -15}; 487 SkPoint origin = {30, 110}; 488 for (auto scale : {1, 2, 3, 5}) { 489 paint.setStrokeWidth(scale * 5); 490 paint.setARGB(0x7f, 0x9f, 0xbf, 0x33 * scale); 491 point.scale(scale); 492 canvas->drawLine(origin, origin + point, paint); 493 } 494## 495 496#SeeAlso operator*(SkScalar scale) const operator*=(SkScalar scale) setLength 497 498#Method ## 499 500# ------------------------------------------------------------------------------ 501 502#Method void negate() 503#In Operators 504#Line # reverses the sign of both members ## 505#Populate 506 507#Example 508SkPoint test[] = { {0.f, -0.f}, {-1, -2}, 509 { SK_ScalarInfinity, SK_ScalarNegativeInfinity }, 510 { SK_ScalarNaN, -SK_ScalarNaN } }; 511for (const SkPoint& pt : test) { 512 SkPoint negPt = pt; 513 negPt.negate(); 514 SkDebugf("pt: %g, %g negate: %g, %g\n", pt.fX, pt.fY, negPt.fX, negPt.fY); 515} 516#StdOut 517pt: 0, -0 negate: -0, 0 518pt: -1, -2 negate: 1, 2 519pt: inf, -inf negate: -inf, inf 520pt: nan, -nan negate: -nan, nan 521## 522## 523 524#SeeAlso operator-() const setAbs 525 526#Method ## 527 528# ------------------------------------------------------------------------------ 529 530#Method SkPoint operator-() const 531 532#Line # reverses sign of Point ## 533#Populate 534 535#Example 536SkPoint test[] = { {0.f, -0.f}, {-1, -2}, 537 { SK_ScalarInfinity, SK_ScalarNegativeInfinity }, 538 { SK_ScalarNaN, -SK_ScalarNaN } }; 539for (const SkPoint& pt : test) { 540 SkPoint negPt = -pt; 541 SkDebugf("pt: %g, %g negate: %g, %g\n", pt.fX, pt.fY, negPt.fX, negPt.fY); 542} 543#StdOut 544pt: 0, -0 negate: -0, 0 545pt: -1, -2 negate: 1, 2 546pt: inf, -inf negate: -inf, inf 547pt: nan, -nan negate: -nan, nan 548## 549## 550 551#SeeAlso negate operator-(const SkPoint& a, const SkPoint& b) operator-=(const SkVector& v) SkIPoint::operator-() const 552 553#Method ## 554 555# ------------------------------------------------------------------------------ 556 557#Method void operator+=(const SkVector& v) 558 559#Line # adds Vector to Point ## 560Adds Vector v to Point. Sets Point to: #Formula # (fX + v.fX, fY + v.fY) ##. 561 562#Param v Vector to add ## 563 564#Example 565#Height 128 566 SkPaint paint; 567 paint.setAntiAlias(true); 568 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 569 { 6, 4 }, { 7, 5 }, { 5, 7 }, 570 { 4, 6 }, { 3, 7 }, { 1, 5 }, 571 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 572 canvas->scale(30, 15); 573 paint.setStyle(SkPaint::kStroke_Style); 574 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 575 points[1] += {1, 1}; 576 points[2] += {-1, -1}; 577 paint.setColor(SK_ColorRED); 578 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 579## 580 581#SeeAlso offset() operator+(const SkPoint& a, const SkVector& b) SkIPoint::operator+=(const SkIVector& v) 582 583#Method ## 584 585# ------------------------------------------------------------------------------ 586 587#Method void operator-=(const SkVector& v) 588 589#Line # subtracts Vector from Point ## 590Subtracts Vector v from Point. Sets Point to: #Formula # (fX - v.fX, fY - v.fY) ##. 591 592#Param v Vector to subtract ## 593 594#Example 595#Height 128 596 SkPaint paint; 597 paint.setAntiAlias(true); 598 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 599 { 6, 4 }, { 7, 5 }, { 5, 7 }, 600 { 4, 6 }, { 3, 7 }, { 1, 5 }, 601 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 602 canvas->scale(30, 15); 603 paint.setStyle(SkPaint::kStroke_Style); 604 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 605 points[1] -= {1, 1}; 606 points[2] -= {-1, -1}; 607 paint.setColor(SK_ColorRED); 608 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 609## 610 611#SeeAlso offset() operator-(const SkPoint& a, const SkPoint& b) SkIPoint::operator-=(const SkIVector& v) 612 613#Method ## 614 615# ------------------------------------------------------------------------------ 616 617#Method SkPoint operator*(SkScalar scale) const 618 619#Line # returns Point multiplied by scale ## 620#Populate 621 622#Example 623#Height 128 624 SkPaint paint; 625 paint.setAntiAlias(true); 626 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 627 { 6, 4 }, { 7, 5 }, { 5, 7 }, 628 { 4, 6 }, { 3, 7 }, { 1, 5 }, 629 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 630 canvas->scale(15, 10); 631 paint.setStyle(SkPaint::kStroke_Style); 632 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 633 for (auto& point : points) { 634 point = point * 1.5f; 635 } 636 paint.setColor(SK_ColorRED); 637 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 638## 639 640#SeeAlso operator*=(SkScalar scale) scale() setLength setNormalize 641 642#Method ## 643 644# ------------------------------------------------------------------------------ 645 646#Method SkPoint& operator*=(SkScalar scale) 647 648#Line # multiplies Point by scale factor ## 649Multiplies Point by scale. Sets Point to: #Formula # (fX * scale, fY * scale) ##. 650 651#Param scale Scalar to multiply by ## 652 653#Return reference to Point ## 654 655#Example 656#Height 128 657 SkPaint paint; 658 paint.setAntiAlias(true); 659 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 660 { 6, 4 }, { 7, 5 }, { 5, 7 }, 661 { 4, 6 }, { 3, 7 }, { 1, 5 }, 662 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 663 canvas->scale(15, 10); 664 paint.setStyle(SkPaint::kStroke_Style); 665 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 666 for (auto& point : points) { 667 point *= 2; 668 } 669 paint.setColor(SK_ColorRED); 670 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 671## 672 673#SeeAlso operator*(SkScalar scale) const scale() setLength setNormalize 674 675#Method ## 676 677# ------------------------------------------------------------------------------ 678 679#Method bool isFinite() const 680#In Property 681#Line # returns true if no member is infinite or NaN ## 682#Populate 683 684#Example 685SkPoint test[] = { {0, -0.f}, {-1, -2}, {SK_ScalarInfinity, 1}, {SK_ScalarNaN, -1} }; 686for (const SkPoint& pt : test) { 687 SkDebugf("pt: %g, %g finite: %s\n", pt.fX, pt.fY, pt.isFinite() ? "true" : "false"); 688} 689#StdOut 690pt: 0, -0 finite: true 691pt: -1, -2 finite: true 692pt: inf, 1 finite: false 693pt: nan, -1 finite: false 694## 695## 696 697#SeeAlso SkRect::isFinite SkPath::isFinite 698 699#Method ## 700 701# ------------------------------------------------------------------------------ 702 703#Method bool equals(SkScalar x, SkScalar y) const 704#In Operators 705#Line # returns true if Points are equal ## 706#Populate 707 708#Example 709SkPoint test[] = { {0, -0.f}, {-1, -2}, {SK_ScalarInfinity, 1}, {SK_ScalarNaN, -1} }; 710for (const SkPoint& pt : test) { 711 SkDebugf("pt: %g, %g %c= pt\n", pt.fX, pt.fY, pt.equals(pt.fX, pt.fY) ? '=' : '!'); 712} 713#StdOut 714pt: 0, -0 == pt 715pt: -1, -2 == pt 716pt: inf, 1 == pt 717pt: nan, -1 != pt 718## 719## 720 721#SeeAlso operator==(const SkPoint& a, const SkPoint& b) 722 723#Method ## 724 725# ------------------------------------------------------------------------------ 726 727#Method bool operator==(const SkPoint& a, const SkPoint& b) 728 729#Line # returns true if Point are equal ## 730#Populate 731 732#Example 733SkPoint test[] = { {0, -0.f}, {-1, -2}, {SK_ScalarInfinity, 1}, {SK_ScalarNaN, -1} }; 734for (const SkPoint& pt : test) { 735 SkDebugf("pt: %g, %g %c= pt\n", pt.fX, pt.fY, pt == pt ? '=' : '!'); 736} 737#StdOut 738pt: 0, -0 == pt 739pt: -1, -2 == pt 740pt: inf, 1 == pt 741pt: nan, -1 != pt 742## 743## 744 745#SeeAlso equals() operator!=(const SkPoint& a, const SkPoint& b) 746 747#Method ## 748 749# ------------------------------------------------------------------------------ 750 751#Method bool operator!=(const SkPoint& a, const SkPoint& b) 752 753#Line # returns true if Point are unequal ## 754#Populate 755 756#Example 757SkPoint test[] = { {0, -0.f}, {-1, -2}, {SK_ScalarInfinity, 1}, {SK_ScalarNaN, -1} }; 758for (const SkPoint& pt : test) { 759 SkDebugf("pt: %g, %g %c= pt\n", pt.fX, pt.fY, pt != pt ? '!' : '='); 760} 761#StdOut 762pt: 0, -0 == pt 763pt: -1, -2 == pt 764pt: inf, 1 == pt 765pt: nan, -1 != pt 766## 767## 768 769#SeeAlso operator==(const SkPoint& a, const SkPoint& b) equals() 770 771#Method ## 772 773# ------------------------------------------------------------------------------ 774 775#Method SkVector operator-(const SkPoint& a, const SkPoint& b) 776 777#Line # returns Vector between Points ## 778Returns Vector from b to a, computed as #Formula # (a.fX - b.fX, a.fY - b.fY) ##. 779 780Can also be used to subtract Vector from Point, returning Point. 781Can also be used to subtract Vector from Vector, returning Vector. 782 783#Param a Point to subtract from ## 784#Param b Point to subtract ## 785 786#Return Vector from b to a ## 787 788#Example 789 SkPaint paint; 790 paint.setAntiAlias(true); 791 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 792 { 6, 4 }, { 7, 5 }, { 5, 7 }, 793 { 4, 6 }, { 3, 7 }, { 1, 5 }, 794 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 795 canvas->scale(30, 15); 796 paint.setStyle(SkPaint::kStroke_Style); 797 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 798 points[1] += points[0] - points[2]; 799 points[2] -= points[3] - points[5]; 800 paint.setColor(SK_ColorRED); 801 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 802## 803 804#SeeAlso operator-=(const SkVector& v) offset() 805 806#Method ## 807 808# ------------------------------------------------------------------------------ 809 810#Method SkPoint operator+(const SkPoint& a, const SkVector& b) 811 812#Line # returns Point offset by Vector ## 813Returns Point resulting from Point a offset by Vector b, computed as: 814#Formula # (a.fX + b.fX, a.fY + b.fY) ##. 815 816Can also be used to offset Point b by Vector a, returning Point. 817Can also be used to add Vector to Vector, returning Vector. 818 819#Param a Point or Vector to add to ## 820#Param b Point or Vector to add ## 821 822#Return Point equal to a offset by b ## 823 824#Example 825 SkPaint paint; 826 paint.setAntiAlias(true); 827 SkPoint points[] = { { 3, 1 }, { 4, 2 }, { 5, 1 }, { 7, 3 }, 828 { 6, 4 }, { 7, 5 }, { 5, 7 }, 829 { 4, 6 }, { 3, 7 }, { 1, 5 }, 830 { 2, 4 }, { 1, 3 }, { 3, 1 } }; 831 canvas->scale(30, 15); 832 paint.setStyle(SkPaint::kStroke_Style); 833 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 834 SkVector mod = {1, 1}; 835 for (auto& point : points) { 836 point = point + mod; 837 mod.fX *= 1.1f; 838 mod.fY += .2f; 839 } 840 paint.setColor(SK_ColorRED); 841 canvas->drawPoints(SkCanvas::kPolygon_PointMode, SK_ARRAY_COUNT(points), points, paint); 842## 843 844#SeeAlso operator+=(const SkVector& v) offset() 845 846#Method ## 847 848# ------------------------------------------------------------------------------ 849 850#Method static SkScalar Length(SkScalar x, SkScalar y) 851#In Property 852#Line # returns straight-line distance to origin ## 853#Populate 854 855#Example 856#Height 192 857 SkPaint paint; 858 paint.setAntiAlias(true); 859 const SkPoint points[] = { { 90, 30 }, { 120, 150 }, { 150, 30 }, { 210, 90 } }; 860 const SkPoint origin = {30, 140}; 861 for (auto point : points) { 862 canvas->drawLine(origin, point, paint); 863 SkAutoCanvasRestore acr(canvas, true); 864 SkScalar angle = SkScalarATan2((point.fY - origin.fY), point.fX - origin.fX); 865 canvas->rotate(angle * 180 / SK_ScalarPI, origin.fX, origin.fY); 866 SkString length("length = "); 867 length.appendScalar(SkPoint::Length(point.fX, point.fY)); 868 canvas->drawString(length, origin.fX + 25, origin.fY - 4, paint); 869 } 870## 871 872#SeeAlso length() Distance setLength 873 874#Method ## 875 876# ------------------------------------------------------------------------------ 877 878#Method static SkScalar Normalize(SkVector* vec) 879#In Offset 880#Line # sets length to one, and returns prior length ## 881#Populate 882 883#Example 884 SkPaint paint; 885 paint.setAntiAlias(true); 886 const SkPoint lines[][2] = { {{ 30, 110 }, { 190, 30 }}, 887 {{ 30, 220 }, { 120, 140 }}}; 888 for (auto line : lines) { 889 canvas->drawLine(line[0], line[1], paint); 890 SkVector vector = line[1] - line[0]; 891 SkScalar priorLength = SkPoint::Normalize(&vector); 892 SkVector rotate90 = { -vector.fY, vector.fX }; 893 rotate90 *= 10.f; 894 canvas->drawLine(line[0] - rotate90, line[0] + rotate90, paint); 895 canvas->drawLine(line[1] - rotate90, line[1] + rotate90, paint); 896 SkString length("length = "); 897 length.appendScalar(priorLength); 898 canvas->drawString(length, line[0].fX + 25, line[0].fY - 4, paint); 899 } 900## 901 902#SeeAlso normalize() setLength Length 903 904#Method ## 905 906# ------------------------------------------------------------------------------ 907 908#Method static SkScalar Distance(const SkPoint& a, const SkPoint& b) 909#In Property 910#Line # returns straight-line distance between points ## 911#Populate 912 913#Example 914#Height 192 915 SkPaint paint; 916 paint.setAntiAlias(true); 917 const SkPoint lines[][2] = {{{-10, -10}, {90, 30}}, {{0, 0}, {150, 30}}, {{10, 25}, {120, 150}}}; 918 const SkPoint origin = {30, 160}; 919 for (auto line : lines) { 920 SkPoint a = origin + line[0]; 921 const SkPoint& b = line[1]; 922 canvas->drawLine(a, b, paint); 923 SkAutoCanvasRestore acr(canvas, true); 924 SkScalar angle = SkScalarATan2((b.fY - a.fY), b.fX - a.fX); 925 canvas->rotate(angle * 180 / SK_ScalarPI, a.fX, a.fY); 926 SkString distance("distance = "); 927 distance.appendScalar(SkPoint::Distance(a, b)); 928 canvas->drawString(distance, a.fX + 25, a.fY - 4, paint); 929 } 930## 931 932#SeeAlso length() setLength 933 934#Method ## 935 936# ------------------------------------------------------------------------------ 937 938#Method static SkScalar DotProduct(const SkVector& a, const SkVector& b) 939#In Operators 940#Line # returns dot product ## 941#Populate 942 943#Example 944 SkPaint paint; 945 paint.setAntiAlias(true); 946 SkVector vectors[][2] = {{{50, 2}, {-14, 20}}, {{0, 50}, {-50, 0}}, {{-20, 25}, {25, -20}}, 947 {{-20, -24}, {-24, -20}}}; 948 SkPoint center[] = {{32, 32}, {160, 32}, {32, 160}, {160, 160}}; 949 paint.setStrokeWidth(2); 950 for (size_t i = 0; i < 4; ++i) { 951 canvas->drawLine(center[i], center[i] + vectors[i][0], paint); 952 canvas->drawLine(center[i], center[i] + vectors[i][1], paint); 953 SkString str; 954 str.printf("dot = %g", SkPoint::DotProduct(vectors[i][0], vectors[i][1])); 955 canvas->drawString(str, center[i].fX, center[i].fY, paint); 956 } 957## 958 959#SeeAlso dot CrossProduct 960 961#Method ## 962 963# ------------------------------------------------------------------------------ 964 965#Method static SkScalar CrossProduct(const SkVector& a, const SkVector& b) 966#In Operators 967#Line # returns cross product ## 968#Populate 969 970#Example 971 SkPaint paint; 972 paint.setAntiAlias(true); 973 SkVector vectors[][2] = {{{50, 2}, {-14, 20}}, {{0, 50}, {-50, 0}}, {{-20, 25}, {25, -20}}, 974 {{-20, -24}, {-24, -20}}}; 975 SkPoint center[] = {{32, 32}, {160, 32}, {32, 160}, {160, 160}}; 976 paint.setStrokeWidth(2); 977 for (size_t i = 0; i < 4; ++i) { 978 paint.setColor(SK_ColorRED); 979 canvas->drawLine(center[i], center[i] + vectors[i][0], paint); 980 paint.setColor(SK_ColorBLUE); 981 canvas->drawLine(center[i], center[i] + vectors[i][1], paint); 982 SkString str; 983 SkScalar cross = SkPoint::CrossProduct(vectors[i][1], vectors[i][0]); 984 str.printf("cross = %g", cross); 985 paint.setColor(cross >= 0 ? SK_ColorRED : SK_ColorBLUE); 986 canvas->drawString(str, center[i].fX, center[i].fY, paint); 987 } 988## 989 990#SeeAlso cross DotProduct 991 992#Method ## 993 994# ------------------------------------------------------------------------------ 995 996#Method SkScalar cross(const SkVector& vec) const 997#In Operators 998#Line # returns cross product ## 999#Populate 1000 1001#Example 1002 SkPaint paint; 1003 paint.setAntiAlias(true); 1004 SkVector vectors[][2] = {{{50, 2}, {-14, 20}}, {{0, 50}, {-50, 0}}, {{-20, 25}, {25, -20}}, 1005 {{-20, -24}, {-24, -20}}}; 1006 SkPoint center[] = {{32, 32}, {160, 32}, {32, 160}, {160, 160}}; 1007 paint.setStrokeWidth(2); 1008 for (size_t i = 0; i < 4; ++i) { 1009 paint.setColor(SK_ColorRED); 1010 canvas->drawLine(center[i], center[i] + vectors[i][0], paint); 1011 paint.setColor(SK_ColorBLUE); 1012 canvas->drawLine(center[i], center[i] + vectors[i][1], paint); 1013 SkString str; 1014 SkScalar cross = vectors[i][0].cross(vectors[i][1]); 1015 str.printf("cross = %g", cross); 1016 paint.setColor(cross >= 0 ? SK_ColorRED : SK_ColorBLUE); 1017 canvas->drawString(str, center[i].fX, center[i].fY, paint); 1018 } 1019## 1020 1021#SeeAlso CrossProduct dot 1022 1023#Method ## 1024 1025# ------------------------------------------------------------------------------ 1026 1027#Method SkScalar dot(const SkVector& vec) const 1028#In Operators 1029#Line # returns dot product ## 1030#Populate 1031 1032#Example 1033 SkPaint paint; 1034 paint.setAntiAlias(true); 1035 SkVector vectors[][2] = {{{50, 2}, {-14, 20}}, {{0, 50}, {-50, 0}}, {{-20, 25}, {25, -20}}, 1036 {{-20, -24}, {-24, -20}}}; 1037 SkPoint center[] = {{32, 32}, {160, 32}, {32, 160}, {160, 160}}; 1038 paint.setStrokeWidth(2); 1039 for (size_t i = 0; i < 4; ++i) { 1040 canvas->drawLine(center[i], center[i] + vectors[i][0], paint); 1041 canvas->drawLine(center[i], center[i] + vectors[i][1], paint); 1042 SkString str; 1043 str.printf("dot = %g", vectors[i][0].dot(vectors[i][1])); 1044 canvas->drawString(str, center[i].fX, center[i].fY, paint); 1045 } 1046## 1047 1048#SeeAlso DotProduct cross 1049 1050#Method ## 1051 1052#Struct SkPoint ## 1053 1054 1055# ------------------------------------------------------------------------------ 1056 1057#Subtopic Vector 1058#Line # alias for Point ## 1059 #Alias Vector ## 1060 #Alias Vectors ## 1061 #Typedef SkPoint SkVector 1062 #Line # alias for Point ## 1063 #Code 1064 typedef SkPoint SkVector; 1065 ## 1066 SkVector provides an alternative name for SkPoint. SkVector and SkPoint can 1067 be used interchangeably for all purposes. 1068 #Typedef ## 1069## 1070 1071#Topic Point ## 1072