| Flutter Impeller |

round_superellipse_param.cc
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "flutter/impeller/geometry/round_superellipse_param.h"
6
7 namespace impeller {
8
9 namespace {
10
11 // Return the value that splits the range from `left` to `right` into two
12 // portions whose ratio equals to `ratio_left` : `ratio_right`.
13 Scalar Split(Scalar left, Scalar right, Scalar ratio_left, Scalar ratio_right) {
14 if (ratio_left == 0 && ratio_right == 0) {
15 return (left + right) / 2;
16 }
17 return (left * ratio_right + right * ratio_left) / (ratio_left + ratio_right);
18 }
19
20 // Return the same Point, but each NaN coordinate is replaced by that of
21 // `default_size`.
22 inline Point ReplanceNaNWithDefault(Point in, Size default_size) {
23 return Point{std::isnan(in.x) ? default_size.width : in.x,
24 std::isnan(in.y) ? default_size.height : in.y};
25 }
26
27 // Swap the x and y coordinate of a point.
28 //
29 // Effectively mirrors the point by the y=x line.
30 inline Point Flip(Point a) {
31 return Point{a.y, a.x};
32 }
33
34 // A look up table with precomputed variables.
35 //
36 // The columns represent the following variabls respectively:
37 //
38 // * n
39 // * k_xJ, which is defined as 1 / (1 - xJ / a)
40 //
41 // For definition of the variables, see ComputeOctant.
42 constexpr Scalar kPrecomputedVariables[][2] = {
43 /*ratio=2.00*/ {2.00000000, 1.13276676},
44 /*ratio=2.10*/ {2.18349805, 1.20311921},
45 /*ratio=2.20*/ {2.33888662, 1.28698796},
46 /*ratio=2.30*/ {2.48660575, 1.36351941},
47 /*ratio=2.40*/ {2.62226596, 1.44717976},
48 /*ratio=2.50*/ {2.75148990, 1.53385819},
49 /*ratio=3.00*/ {3.36298265, 1.98288283},
50 /*ratio=3.50*/ {4.08649929, 2.23811846},
51 /*ratio=4.00*/ {4.85481134, 2.47563463},
52 /*ratio=4.50*/ {5.62945551, 2.72948597},
53 /*ratio=5.00*/ {6.43023796, 2.98020421}};
54
55 constexpr Scalar kMinRatio = 2.00;
56
57 // The curve is split into 3 parts:
58 // * The first part uses a denser look up table.
59 // * The second part uses a sparser look up table.
60 // * The third part uses a straight line.
61 constexpr Scalar kFirstStepInverse = 10; // = 1 / 0.10
62 constexpr Scalar kFirstMaxRatio = 2.50;
63 constexpr Scalar kFirstNumRecords = 6;
64
65 constexpr Scalar kSecondStepInverse = 2; // = 1 / 0.50
66 constexpr Scalar kSecondMaxRatio = 5.00;
67
68 constexpr Scalar kThirdNSlope = 1.559599389;
69 constexpr Scalar kThirdKxjSlope = 0.522807185;
70
71 constexpr size_t kNumRecords =
72 sizeof(kPrecomputedVariables) / sizeof(kPrecomputedVariables[0]);
73
74 // Compute the `n` and `xJ / a` for the given ratio.
75 std::array<Scalar, 2> ComputeNAndXj(Scalar ratio) {
76 if (ratio > kSecondMaxRatio) {
77 Scalar n = kThirdNSlope * (ratio - kSecondMaxRatio) +
78 kPrecomputedVariables[kNumRecords - 1][0];
79 Scalar k_xJ = kThirdKxjSlope * (ratio - kSecondMaxRatio) +
80 kPrecomputedVariables[kNumRecords - 1][1];
81 return {n, 1 - 1 / k_xJ};
82 }
83 ratio = std::clamp(ratio, kMinRatio, kSecondMaxRatio);
84 Scalar steps;
85 if (ratio < kFirstMaxRatio) {
86 steps = (ratio - kMinRatio) * kFirstStepInverse;
87 } else {
88 steps =
89 (ratio - kFirstMaxRatio) * kSecondStepInverse + kFirstNumRecords - 1;
90 }
91
92 size_t left = std::clamp<size_t>(static_cast<size_t>(std::floor(steps)), 0,
93 kNumRecords - 2);
94 Scalar frac = steps - left;
95
96 Scalar n = (1 - frac) * kPrecomputedVariables[left][0] +
97 frac * kPrecomputedVariables[left + 1][0];
98 Scalar k_xJ = (1 - frac) * kPrecomputedVariables[left][1] +
99 frac * kPrecomputedVariables[left + 1][1];
100 return {n, 1 - 1 / k_xJ};
101 }
102
103 // Find the center of the circle that passes the given two points and have the
104 // given radius.
105 Point FindCircleCenter(Point a, Point b, Scalar r) {
106 /* Denote the middle point of A and B as M. The key is to find the center of
107 * the circle.
108 * A --__
109 * / ⟍ `、
110 * / M ⟍\
111 * / ⟋ B
112 * / ⟋ ↗
113 * / ⟋
114 * / ⟋ r
115 * C ᜱ ↙
116 */
117
118 Point a_to_b = b - a;
119 Point m = (a + b) / 2;
120 Point c_to_m = Point(-a_to_b.y, a_to_b.x);
121 Scalar distance_am = a_to_b.GetLength() / 2;
122 Scalar distance_cm = sqrt(r * r - distance_am * distance_am);
123 return m - distance_cm * c_to_m.Normalize();
124 }
125
126 // Compute parameters for a square-like rounded superellipse with a symmetrical
127 // radius.
128 RoundSuperellipseParam::Octant ComputeOctant(Point center,
129 Scalar a,
130 Scalar radius) {
131 /* The following figure shows the first quadrant of a square-like rounded
132 * superellipse.
133 *
134 * superelipse
135 * A ↓ circular arc
136 * ---------...._J ↙
137 * | / `⟍ M (where x=y)
138 * | / ⟋ ⟍
139 * | / ⟋ \
140 * | / ⟋ |
141 * | ᜱD |
142 * | ⟋ |
143 * | ⟋ |
144 * |⟋ |
145 * +--------------------| A'
146 * O
147 * ←-------- a ---------→
148 */
149
150 if (radius <= 0) {
151 return RoundSuperellipseParam::Octant{
152 .offset = center,
153
154 .se_a = a,
155 .se_n = 0,
156
157 .circle_start = {a, a},
158 };
159 }
160
161 Scalar ratio = a * 2 / radius;
162 Scalar g = RoundSuperellipseParam::kGapFactor * radius;
163
164 auto precomputed_vars = ComputeNAndXj(ratio);
165 Scalar n = precomputed_vars[0];
166 Scalar xJ = precomputed_vars[1] * a;
167 Scalar yJ = pow(1 - pow(precomputed_vars[1], n), 1 / n) * a;
168 Scalar max_theta = asinf(pow(precomputed_vars[1], n / 2));
169
170 Scalar tan_phiJ = pow(xJ / yJ, n - 1);
171 Scalar d = (xJ - tan_phiJ * yJ) / (1 - tan_phiJ);
172 Scalar R = (a - d - g) * sqrt(2);
173
174 Point pointM{a - g, a - g};
175 Point pointJ = Point{xJ, yJ};
176 Point circle_center =
177 radius == 0 ? pointM : FindCircleCenter(pointJ, pointM, R);
178 Radians circle_max_angle =
179 radius == 0 ? Radians(0)
180 : (pointM - circle_center).AngleTo(pointJ - circle_center);
181
182 return RoundSuperellipseParam::Octant{
183 .offset = center,
184
185 .se_a = a,
186 .se_n = n,
187 .se_max_theta = max_theta,
188
189 .circle_start = pointJ,
190 .circle_center = circle_center,
191 .circle_max_angle = circle_max_angle,
192 };
193 }
194
195 // Compute parameters for a quadrant of a rounded superellipse with asymmetrical
196 // radii.
197 //
198 // The `corner` is the coordinate of the corner point in the same coordinate
199 // space as `center`, which specifies the half size of the bounding box.
200 //
201 // The `sign` is a vector of {±1, ±1} that specifies which quadrant the curve
202 // should be, which should have the same sign as `corner - center` except that
203 // the latter may have a 0.
204 RoundSuperellipseParam::Quadrant ComputeQuadrant(Point center,
205 Point corner,
206 Size in_radii,
207 Size sign) {
208 Point corner_vector = corner - center;
209 Size radii = in_radii.Abs();
210
211 // The prefix "norm" is short for "normalized".
212 //
213 // Be extra careful to avoid NaNs in cases that some coordinates of `in_radii`
214 // or `corner_vector` are zero.
215 Scalar norm_radius = radii.MinDimension();
216 Size forward_scale = norm_radius == 0 ? Size{1, 1} : radii / norm_radius;
217 Point norm_half_size = corner_vector.Abs() / forward_scale;
218 Point signed_scale =
219 ReplanceNaNWithDefault(corner_vector / norm_half_size, sign);
220
221 // Each quadrant curve is composed of two octant curves, each of which belongs
222 // to a square-like rounded rectangle. For the two octants to connect at the
223 // circular arc, the centers these two square-like rounded rectangle must be
224 // offset from the quadrant center by a same distance in different directions.
225 // The distance is denoted as `c`.
226 Scalar c = norm_half_size.x - norm_half_size.y;
227
228 return RoundSuperellipseParam::Quadrant{
229 .offset = center,
230 .signed_scale = signed_scale,
231 .top = ComputeOctant(Point{0, -c}, norm_half_size.x, norm_radius),
232 .right = ComputeOctant(Point{c, 0}, norm_half_size.y, norm_radius),
233 };
234 }
235
236 // Checks whether the given point is contained in the first octant of the given
237 // square-like rounded superellipse.
238 //
239 // The first octant refers to the region that spans from 0 to pi/4 starting from
240 // positive Y axis clockwise.
241 //
242 // If the point is not within this octant at all, then this function always
243 // returns true. Otherwise this function returns whether the point is contained
244 // within the rounded superellipse.
245 //
246 // The `param.offset` is ignored. The input point should have been transformed
247 // to the coordinate space where the rounded superellipse is centered at the
248 // origin.
249 bool OctantContains(const RoundSuperellipseParam::Octant& param,
250 const Point& p) {
251 // Check whether the point is within the octant.
252 if (p.x < 0 || p.y < 0 || p.y < p.x) {
253 return true;
254 }
255 // Check if the point is within the superellipsoid segment.
256 if (p.x <= param.circle_start.x) {
257 Point p_se = p / param.se_a;
258 return powf(p_se.x, param.se_n) + powf(p_se.y, param.se_n) <= 1;
259 }
260 Scalar circle_radius =
261 param.circle_start.GetDistanceSquared(param.circle_center);
262 Point p_circle = p - param.circle_center;
263 return p_circle.GetDistanceSquared(Point()) < circle_radius;
264 }
265
266 // Determine if p is inside the corner curve defined by the indicated corner
267 // param.
268 //
269 // The coordinates of p should be within the same coordinate space with
270 // `param.offset`.
271 //
272 // If `check_quadrant` is true, then this function first checks if the point is
273 // within the quadrant of given corner. If not, this function returns true,
274 // otherwise this method continues to check whether the point is contained in
275 // the rounded superellipse.
276 //
277 // If `check_quadrant` is false, then the first step above is skipped, and the
278 // function checks whether the absolute (relative to the center) coordinate of p
279 // is contained in the rounded superellipse.
280 bool CornerContains(const RoundSuperellipseParam::Quadrant& param,
281 const Point& p,
282 bool check_quadrant = true) {
283 Point norm_point = (p - param.offset) / param.signed_scale;
284 if (check_quadrant) {
285 if (norm_point.x < 0 || norm_point.y < 0) {
286 return true;
287 }
288 } else {
289 norm_point = norm_point.Abs();
290 }
291 if (param.top.se_n < 2 || param.right.se_n < 2) {
292 // A rectangular corner. The top and left sides contain the borders
293 // while the bottom and right sides don't (see `Rect.contains`).
294 Scalar x_delta = param.right.offset.x + param.right.se_a - norm_point.x;
295 Scalar y_delta = param.top.offset.y + param.top.se_a - norm_point.y;
296 bool x_within = x_delta > 0 || (x_delta == 0 && param.signed_scale.x < 0);
297 bool y_within = y_delta > 0 || (y_delta == 0 && param.signed_scale.y < 0);
298 return x_within && y_within;
299 }
300 return OctantContains(param.top, norm_point - param.top.offset) &&
301 OctantContains(param.right, Flip(norm_point - param.right.offset));
302 }
303
304 class RoundSuperellipseBuilder {
305 public:
306 explicit RoundSuperellipseBuilder(PathReceiver& receiver)
307 : receiver_(receiver) {}
308
309 // Draws an arc representing 1/4 of a rounded superellipse.
310 //
311 // If `reverse` is false, the resulting arc spans from 0 to pi/2, moving
312 // clockwise starting from the positive Y-axis. Otherwise it moves from pi/2
313 // to 0.
314 //
315 // The `scale_sign` is an additional scaling transformation that potentially
316 // flips the result. This is useful for uniform radii where the same quadrant
317 // parameter set should be drawn to 4 quadrants.
318 void AddQuadrant(const RoundSuperellipseParam::Quadrant& param,
319 bool reverse,
320 Point scale_sign = Point(1, 1)) {
321 auto transform = Matrix::MakeTranslateScale(param.signed_scale * scale_sign,
322 param.offset);
323 if (param.top.se_n < 2 || param.right.se_n < 2) {
324 receiver_.LineTo(transform * (param.top.offset +
325 Point(param.top.se_a, param.top.se_a)));
326 if (!reverse) {
327 receiver_.LineTo(transform *
328 (param.right.offset + Point(param.right.se_a, 0)));
329 } else {
330 receiver_.LineTo(transform *
331 (param.top.offset + Point(0, param.top.se_a)));
332 }
333 return;
334 }
335 if (!reverse) {
336 AddOctant(param.top, /*reverse=*/false, /*flip=*/false, transform);
337 AddOctant(param.right, /*reverse=*/true, /*flip=*/true, transform);
338 } else {
339 AddOctant(param.right, /*reverse=*/false, /*flip=*/true, transform);
340 AddOctant(param.top, /*reverse=*/true, /*flip=*/false, transform);
341 }
342 }
343
344 private:
345 std::array<Point, 4> SuperellipseArcPoints(
346 const RoundSuperellipseParam::Octant& param) {
347 Point start = {0, param.se_a};
348 const Point& end = param.circle_start;
349 constexpr Point start_tangent = {1, 0};
350 Point circle_start_vector = param.circle_start - param.circle_center;
351 Point end_tangent =
352 Point{-circle_start_vector.y, circle_start_vector.x}.Normalize();
353
354 std::array<Scalar, 2> factors = SuperellipseBezierFactors(param.se_n);
355
356 return std::array<Point, 4>{
357 start, start + start_tangent * factors[0] * param.se_a,
358 end + end_tangent * factors[1] * param.se_a, end};
359 };
360
361 std::array<Point, 4> CircularArcPoints(
362 const RoundSuperellipseParam::Octant& param) {
363 Point start_vector = param.circle_start - param.circle_center;
364 Point end_vector =
365 start_vector.Rotate(Radians(-param.circle_max_angle.radians));
366 Point circle_end = param.circle_center + end_vector;
367 Point start_tangent = Point{start_vector.y, -start_vector.x}.Normalize();
368 Point end_tangent = Point{-end_vector.y, end_vector.x}.Normalize();
369 Scalar bezier_factor = std::tan(param.circle_max_angle.radians / 4) * 4 / 3;
370 Scalar radius = start_vector.GetLength();
371
372 return std::array<Point, 4>{
373 param.circle_start,
374 param.circle_start + start_tangent * bezier_factor * radius,
375 circle_end + end_tangent * bezier_factor * radius, circle_end};
376 };
377
378 // Draws an arc representing 1/8 of a rounded superellipse.
379 //
380 // If `reverse` is false, the resulting arc spans from 0 to pi/4, moving
381 // clockwise starting from the positive Y-axis. Otherwise it moves from pi/4
382 // to 0.
383 //
384 // If `flip` is true, all points have their X and Y coordinates swapped,
385 // effectively mirrowing each point by the y=x line.
386 //
387 // All points are transformed by `external_transform` after the optional
388 // flipping before being used as control points for the cubic curves.
389 void AddOctant(const RoundSuperellipseParam::Octant& param,
390 bool reverse,
391 bool flip,
392 const Matrix& external_transform) {
393 Matrix transform =
394 external_transform * Matrix::MakeTranslation(param.offset);
395 if (flip) {
396 transform = transform * kFlip;
397 }
398
399 auto circle_points = CircularArcPoints(param);
400 auto se_points = SuperellipseArcPoints(param);
401
402 if (!reverse) {
403 receiver_.CubicTo(transform * se_points[1], transform * se_points[2],
404 transform * se_points[3]);
405 receiver_.CubicTo(transform * circle_points[1],
406 transform * circle_points[2],
407 transform * circle_points[3]);
408 } else {
409 receiver_.CubicTo(transform * circle_points[2],
410 transform * circle_points[1],
411 transform * circle_points[0]);
412 receiver_.CubicTo(transform * se_points[2], transform * se_points[1],
413 transform * se_points[0]);
414 }
415 };
416
417 // Get the Bezier factor for the superellipse arc in a rounded superellipse.
418 //
419 // The result will be assigned to output, where [0] will be the factor for the
420 // starting tangent and [1] for the ending tangent.
421 //
422 // These values are computed by brute-force searching for the minimal distance
423 // on a rounded superellipse and are not for general purpose superellipses.
424 std::array<Scalar, 2> SuperellipseBezierFactors(Scalar n) {
425 constexpr Scalar kPrecomputedVariables[][2] = {
426 /*n=2.0*/ {0.01339448, 0.05994973},
427 /*n=3.0*/ {0.13664115, 0.13592082},
428 /*n=4.0*/ {0.24545546, 0.14099516},
429 /*n=5.0*/ {0.32353151, 0.12808021},
430 /*n=6.0*/ {0.39093068, 0.11726264},
431 /*n=7.0*/ {0.44847800, 0.10808278},
432 /*n=8.0*/ {0.49817452, 0.10026175},
433 /*n=9.0*/ {0.54105583, 0.09344429},
434 /*n=10.0*/ {0.57812578, 0.08748984},
435 /*n=11.0*/ {0.61050961, 0.08224722},
436 /*n=12.0*/ {0.63903989, 0.07759639},
437 /*n=13.0*/ {0.66416338, 0.07346530},
438 /*n=14.0*/ {0.68675338, 0.06974996},
439 /*n=15.0*/ {0.70678034, 0.06529512}};
440 constexpr size_t kNumRecords =
441 sizeof(kPrecomputedVariables) / sizeof(kPrecomputedVariables[0]);
442 constexpr Scalar kStep = 1.00f;
443 constexpr Scalar kMinN = 2.00f;
444 constexpr Scalar kMaxN = kMinN + (kNumRecords - 1) * kStep;
445
446 if (n >= kMaxN) {
447 // Heuristic formula derived from fitting.
448 return {1.07f - expf(1.307649835) * powf(n, -0.8568516731),
449 -0.01f + expf(-0.9287690322) * powf(n, -0.6120901398)};
450 }
451
452 Scalar steps = std::clamp<Scalar>((n - kMinN) / kStep, 0, kNumRecords - 1);
453 size_t left = std::clamp<size_t>(static_cast<size_t>(std::floor(steps)), 0,
454 kNumRecords - 2);
455 Scalar frac = steps - left;
456
457 return std::array<Scalar, 2>{(1 - frac) * kPrecomputedVariables[left][0] +
458 frac * kPrecomputedVariables[left + 1][0],
459 (1 - frac) * kPrecomputedVariables[left][1] +
460 frac * kPrecomputedVariables[left + 1][1]};
461 }
462
463 PathReceiver& receiver_;
464
465 // A matrix that swaps the coordinates of a point.
466 // clang-format off
467 static constexpr Matrix kFlip = Matrix(
468 0.0f, 1.0f, 0.0f, 0.0f,
469 1.0f, 0.0f, 0.0f, 0.0f,
470 0.0f, 0.0f, 1.0f, 0.0f,
471 0.0f, 0.0f, 0.0f, 1.0f);
472 // clang-format on
473 };
474
475 } // namespace
476
477 RoundSuperellipseParam RoundSuperellipseParam::MakeBoundsRadius(
478 const Rect& bounds,
479 Scalar radius) {
480 return RoundSuperellipseParam{
481 .top_right = ComputeQuadrant(bounds.GetCenter(), bounds.GetRightTop(),
482 {radius, radius}, {-1, 1}),
483 .all_corners_same = true,
484 };
485 }
486
487 RoundSuperellipseParam RoundSuperellipseParam::MakeBoundsRadii(
488 const Rect& bounds,
489 const RoundingRadii& radii) {
490 if (radii.AreAllCornersSame() && !radii.top_left.IsEmpty()) {
491 // Having four empty corners indicate a rectangle, which needs special
492 // treatment on border containment and therefore is not `all_corners_same`.
493 return RoundSuperellipseParam{
494 .top_right = ComputeQuadrant(bounds.GetCenter(), bounds.GetRightTop(),
495 radii.top_right, {-1, 1}),
496 .all_corners_same = true,
497 };
498 }
499 Scalar top_split = Split(bounds.GetLeft(), bounds.GetRight(),
500 radii.top_left.width, radii.top_right.width);
501 Scalar right_split = Split(bounds.GetTop(), bounds.GetBottom(),
502 radii.top_right.height, radii.bottom_right.height);
503 Scalar bottom_split =
504 Split(bounds.GetLeft(), bounds.GetRight(), radii.bottom_left.width,
505 radii.bottom_right.width);
506 Scalar left_split = Split(bounds.GetTop(), bounds.GetBottom(),
507 radii.top_left.height, radii.bottom_left.height);
508
509 return RoundSuperellipseParam{
510 .top_right =
511 ComputeQuadrant(Point{top_split, right_split}, bounds.GetRightTop(),
512 radii.top_right, {1, -1}),
513 .bottom_right =
514 ComputeQuadrant(Point{bottom_split, right_split},
515 bounds.GetRightBottom(), radii.bottom_right, {1, 1}),
516 .bottom_left =
517 ComputeQuadrant(Point{bottom_split, left_split},
518 bounds.GetLeftBottom(), radii.bottom_left, {-1, 1}),
519 .top_left =
520 ComputeQuadrant(Point{top_split, left_split}, bounds.GetLeftTop(),
521 radii.top_left, {-1, -1}),
522 .all_corners_same = false,
523 };
524 }
525
526 void RoundSuperellipseParam::Dispatch(PathReceiver& path_receiver) const {
527 RoundSuperellipseBuilder builder(path_receiver);
528
529 Point start = top_right.offset +
530 top_right.signed_scale *
531 (top_right.top.offset + Point(0, top_right.top.se_a));
532 path_receiver.MoveTo(start, true);
533
534 if (all_corners_same) {
535 builder.AddQuadrant(top_right, /*reverse=*/false, Point(1, 1));
536 builder.AddQuadrant(top_right, /*reverse=*/true, Point(1, -1));
537 builder.AddQuadrant(top_right, /*reverse=*/false, Point(-1, -1));
538 builder.AddQuadrant(top_right, /*reverse=*/true, Point(-1, 1));
539 } else {
540 builder.AddQuadrant(top_right, /*reverse=*/false);
541 builder.AddQuadrant(bottom_right, /*reverse=*/true);
542 builder.AddQuadrant(bottom_left, /*reverse=*/false);
543 builder.AddQuadrant(top_left, /*reverse=*/true);
544 }
545
546 path_receiver.LineTo(start);
547 path_receiver.Close();
548 }
549
550 bool RoundSuperellipseParam::Contains(const Point& point) const {
551 if (all_corners_same) {
552 return CornerContains(top_right, point, /*check_quadrant=*/false);
553 }
554 return CornerContains(top_right, point) &&
555 CornerContains(bottom_right, point) &&
556 CornerContains(bottom_left, point) && CornerContains(top_left, point);
557 }
558
559 } // namespace impeller
impeller::PathReceiver
Collection of functions to receive path segments from the underlying path representation via the DlPa...
Definition: path_source.h:42
impeller::PathReceiver::LineTo
virtual void LineTo(const Point &p2)=0
impeller::PathReceiver::Close
virtual void Close()=0
impeller::PathReceiver::MoveTo
virtual void MoveTo(const Point &p2, bool will_be_closed)=0
transform
Matrix transform
Definition: gaussian_blur_filter_contents.cc:214
impeller::saturated::b
SI b
Definition: saturated_math.h:87
impeller
Definition: allocation.cc:12
impeller::Scalar
float Scalar
Definition: scalar.h:19
impeller::CornerContains
static bool CornerContains(const Point &p, const Point &corner, const Point &direction, const Size &radii)
Definition: round_rect.cc:30
impeller::Point
TPoint< Scalar > Point
Definition: point.h:327
impeller::Size
TSize< Scalar > Size
Definition: size.h:159
round_superellipse_param.h
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
impeller::Matrix::MakeTranslateScale
static constexpr Matrix MakeTranslateScale(const Vector3 &s, const Vector3 &t)
Definition: matrix.h:113
impeller::RoundSuperellipseParam::Octant::offset
Point offset
Definition: round_superellipse_param.h:31
impeller::RoundSuperellipseParam::Octant::se_a
Scalar se_a
Definition: round_superellipse_param.h:34
impeller::RoundSuperellipseParam::Quadrant::signed_scale
Point signed_scale
Definition: round_superellipse_param.h:78
impeller::RoundSuperellipseParam::Quadrant::top
Octant top
Definition: round_superellipse_param.h:82
impeller::RoundSuperellipseParam::Quadrant::offset
Point offset
Definition: round_superellipse_param.h:63
impeller::RoundSuperellipseParam
Definition: round_superellipse_param.h:18
impeller::RoundSuperellipseParam::top_left
Quadrant top_left
Definition: round_superellipse_param.h:92
impeller::RoundSuperellipseParam::MakeBoundsRadii
static RoundSuperellipseParam MakeBoundsRadii(const Rect &bounds, const RoundingRadii &radii)
Definition: round_superellipse_param.cc:487
impeller::RoundSuperellipseParam::Dispatch
void Dispatch(PathReceiver &receiver) const
Definition: round_superellipse_param.cc:526
impeller::RoundSuperellipseParam::Contains
bool Contains(const Point &point) const
Definition: round_superellipse_param.cc:550
impeller::RoundSuperellipseParam::bottom_left
Quadrant bottom_left
Definition: round_superellipse_param.h:91
impeller::RoundSuperellipseParam::kGapFactor
static constexpr Scalar kGapFactor
Definition: round_superellipse_param.h:127
impeller::RoundSuperellipseParam::all_corners_same
bool all_corners_same
Definition: round_superellipse_param.h:95
impeller::RoundSuperellipseParam::top_right
Quadrant top_right
Definition: round_superellipse_param.h:89
impeller::RoundSuperellipseParam::MakeBoundsRadius
static RoundSuperellipseParam MakeBoundsRadius(const Rect &bounds, Scalar radius)
Definition: round_superellipse_param.cc:477
impeller::RoundSuperellipseParam::bottom_right
Quadrant bottom_right
Definition: round_superellipse_param.h:90
impeller::RoundingRadii
Definition: rounding_radii.h:14
impeller::RoundingRadii::top_right
Size top_right
Definition: rounding_radii.h:16
impeller::RoundingRadii::bottom_left
Size bottom_left
Definition: rounding_radii.h:17
impeller::RoundingRadii::bottom_right
Size bottom_right
Definition: rounding_radii.h:18
impeller::RoundingRadii::top_left
Size top_left
Definition: rounding_radii.h:15
impeller::RoundingRadii::AreAllCornersSame
constexpr bool AreAllCornersSame(Scalar tolerance=kEhCloseEnough) const
Definition: rounding_radii.h:54
impeller::TPoint< Scalar >
impeller::TPoint::Abs
constexpr TPoint Abs() const
Definition: point.h:216
impeller::TPoint::Rotate
constexpr TPoint Rotate(const Radians &angle) const
Definition: point.h:226
impeller::TPoint::y
Type y
Definition: point.h:31
impeller::TPoint::x
Type x
Definition: point.h:30
impeller::TPoint::GetDistanceSquared
constexpr Type GetDistanceSquared(const TPoint &p) const
Definition: point.h:180
impeller::TRect< Scalar >
impeller::TRect::GetBottom
constexpr auto GetBottom() const
Definition: rect.h:357
impeller::TRect::GetTop
constexpr auto GetTop() const
Definition: rect.h:353
impeller::TRect::GetLeft
constexpr auto GetLeft() const
Definition: rect.h:351
impeller::TRect::GetRight
constexpr auto GetRight() const
Definition: rect.h:355
impeller::TRect::GetLeftBottom
constexpr TPoint< T > GetLeftBottom() const
Definition: rect.h:367
impeller::TRect::GetRightTop
constexpr TPoint< T > GetRightTop() const
Definition: rect.h:363
impeller::TRect::GetRightBottom
constexpr TPoint< T > GetRightBottom() const
Definition: rect.h:371
impeller::TRect::GetCenter
constexpr Point GetCenter() const
Get the center point as a |Point|.
Definition: rect.h:382
impeller::TRect::GetLeftTop
constexpr TPoint< T > GetLeftTop() const
Definition: rect.h:359
impeller::TSize::Abs
constexpr TSize Abs() const
Definition: size.h:108
impeller::TSize::height
Type height
Definition: size.h:29
impeller::TSize::width
Type width
Definition: size.h:28
impeller::TSize::IsEmpty
constexpr bool IsEmpty() const
Returns true if either of the width or height are 0, negative, or NaN.
Definition: size.h:123
start
const size_t start
Definition: tessellator_libtess.cc:62
end
const size_t end
Definition: tessellator_libtess.cc:63