| 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 <= kEhCloseEnough) {
151 // Corners with really small radii are treated as sharp corners, since they
152 // might lead to NaNs due to `ratio` being too large.
153 return RoundSuperellipseParam::Octant{
154 .offset = center,
155
156 .se_a = a,
157 .se_n = 0,
158
159 .circle_start = {a, a},
160 };
161 }
162
163 Scalar ratio = a * 2 / radius;
164 Scalar g = RoundSuperellipseParam::kGapFactor * radius;
165
166 auto precomputed_vars = ComputeNAndXj(ratio);
167 Scalar n = precomputed_vars[0];
168 Scalar xJ = precomputed_vars[1] * a;
169 Scalar yJ = pow(1 - pow(precomputed_vars[1], n), 1 / n) * a;
170 Scalar max_theta = asinf(pow(precomputed_vars[1], n / 2));
171
172 Scalar tan_phiJ = pow(xJ / yJ, n - 1);
173 Scalar d = (xJ - tan_phiJ * yJ) / (1 - tan_phiJ);
174 Scalar R = (a - d - g) * sqrt(2);
175
176 Point pointM{a - g, a - g};
177 Point pointJ = Point{xJ, yJ};
178 Point circle_center =
179 radius == 0 ? pointM : FindCircleCenter(pointJ, pointM, R);
180 Radians circle_max_angle =
181 radius == 0 ? Radians(0)
182 : (pointM - circle_center).AngleTo(pointJ - circle_center);
183
184 return RoundSuperellipseParam::Octant{
185 .offset = center,
186
187 .se_a = a,
188 .se_n = n,
189 .se_max_theta = max_theta,
190
191 .circle_start = pointJ,
192 .circle_center = circle_center,
193 .circle_max_angle = circle_max_angle,
194 };
195 }
196
197 // Compute parameters for a quadrant of a rounded superellipse with asymmetrical
198 // radii.
199 //
200 // The `corner` is the coordinate of the corner point in the same coordinate
201 // space as `center`, which specifies the half size of the bounding box.
202 //
203 // The `sign` is a vector of {±1, ±1} that specifies which quadrant the curve
204 // should be, which should have the same sign as `corner - center` except that
205 // the latter may have a 0.
206 RoundSuperellipseParam::Quadrant ComputeQuadrant(Point center,
207 Point corner,
208 Size in_radii,
209 Size sign) {
210 Point corner_vector = corner - center;
211 Size radii = {std::min(std::abs(in_radii.width), std::abs(corner_vector.x)),
212 std::min(std::abs(in_radii.height), std::abs(corner_vector.y))};
213
214 // The prefix "norm" is short for "normalized", meaning a rounded superellipse
215 // that has a uniform radius. The quadrant is scaled from this normalized one.
216 //
217 // Be extra careful to avoid NaNs in cases that some coordinates of `in_radii`
218 // or `corner_vector` are zero.
219 Scalar norm_radius = radii.MinDimension();
220 Size forward_scale = norm_radius == 0 ? Size{1, 1} : radii / norm_radius;
221 Point norm_half_size = corner_vector.Abs() / forward_scale;
222 Point signed_scale =
223 ReplanceNaNWithDefault(corner_vector / norm_half_size, sign);
224
225 // Each quadrant curve is composed of two octant curves, each of which belongs
226 // to a square-like rounded rectangle. For the two octants to connect at the
227 // circular arc, the centers these two square-like rounded rectangle must be
228 // offset from the quadrant center by a same distance in different directions.
229 // The distance is denoted as `c`.
230 Scalar c = norm_half_size.x - norm_half_size.y;
231
232 return RoundSuperellipseParam::Quadrant{
233 .offset = center,
234 .signed_scale = signed_scale,
235 .top = ComputeOctant(Point{0, -c}, norm_half_size.x, norm_radius),
236 .right = ComputeOctant(Point{c, 0}, norm_half_size.y, norm_radius),
237 };
238 }
239
240 // Checks whether the given point is contained in the first octant of the given
241 // square-like rounded superellipse.
242 //
243 // The first octant refers to the region that spans from 0 to pi/4 starting from
244 // positive Y axis clockwise.
245 //
246 // If the point is not within this octant at all, then this function always
247 // returns true. Otherwise this function returns whether the point is contained
248 // within the rounded superellipse.
249 //
250 // The `param.offset` is ignored. The input point should have been transformed
251 // to the coordinate space where the rounded superellipse is centered at the
252 // origin.
253 bool OctantContains(const RoundSuperellipseParam::Octant& param,
254 const Point& p) {
255 // Check whether the point is within the octant.
256 if (p.x < 0 || p.y < 0 || p.y < p.x) {
257 return true;
258 }
259 // Check if the point is within the superellipsoid segment.
260 if (p.x <= param.circle_start.x) {
261 Point p_se = p / param.se_a;
262 return powf(p_se.x, param.se_n) + powf(p_se.y, param.se_n) <= 1;
263 }
264 Scalar circle_radius =
265 param.circle_start.GetDistanceSquared(param.circle_center);
266 Point p_circle = p - param.circle_center;
267 return p_circle.GetDistanceSquared(Point()) < circle_radius;
268 }
269
270 // Determine if p is inside the corner curve defined by the indicated corner
271 // param.
272 //
273 // The coordinates of p should be within the same coordinate space with
274 // `param.offset`.
275 //
276 // If `check_quadrant` is true, then this function first checks if the point is
277 // within the quadrant of given corner. If not, this function returns true,
278 // otherwise this method continues to check whether the point is contained in
279 // the rounded superellipse.
280 //
281 // If `check_quadrant` is false, then the first step above is skipped, and the
282 // function checks whether the absolute (relative to the center) coordinate of p
283 // is contained in the rounded superellipse.
284 bool CornerContains(const RoundSuperellipseParam::Quadrant& param,
285 const Point& p,
286 bool check_quadrant = true) {
287 Point norm_point = (p - param.offset) / param.signed_scale;
288 if (check_quadrant) {
289 if (norm_point.x < 0 || norm_point.y < 0) {
290 return true;
291 }
292 } else {
293 norm_point = norm_point.Abs();
294 }
295 if (param.top.se_n < 2 || param.right.se_n < 2) {
296 // A rectangular corner. The top and left sides contain the borders
297 // while the bottom and right sides don't (see `Rect.contains`).
298 Scalar x_delta = param.right.offset.x + param.right.se_a - norm_point.x;
299 Scalar y_delta = param.top.offset.y + param.top.se_a - norm_point.y;
300 bool x_within = x_delta > 0 || (x_delta == 0 && param.signed_scale.x < 0);
301 bool y_within = y_delta > 0 || (y_delta == 0 && param.signed_scale.y < 0);
302 return x_within && y_within;
303 }
304 return OctantContains(param.top, norm_point - param.top.offset) &&
305 OctantContains(param.right, Flip(norm_point - param.right.offset));
306 }
307
308 class RoundSuperellipseBuilder {
309 public:
310 explicit RoundSuperellipseBuilder(PathReceiver& receiver)
311 : receiver_(receiver) {}
312
313 // Draws an arc representing 1/4 of a rounded superellipse.
314 //
315 // If `reverse` is false, the resulting arc spans from 0 to pi/2, moving
316 // clockwise starting from the positive Y-axis. Otherwise it moves from pi/2
317 // to 0.
318 //
319 // The `scale_sign` is an additional scaling transformation that potentially
320 // flips the result. This is useful for uniform radii where the same quadrant
321 // parameter set should be drawn to 4 quadrants.
322 void AddQuadrant(const RoundSuperellipseParam::Quadrant& param,
323 bool reverse,
324 Point scale_sign = Point(1, 1)) {
325 auto transform = Matrix::MakeTranslateScale(param.signed_scale * scale_sign,
326 param.offset);
327 if (param.top.se_n < 2 || param.right.se_n < 2) {
328 receiver_.LineTo(transform * (param.top.offset +
329 Point(param.top.se_a, param.top.se_a)));
330 if (!reverse) {
331 receiver_.LineTo(transform *
332 (param.right.offset + Point(param.right.se_a, 0)));
333 } else {
334 receiver_.LineTo(transform *
335 (param.top.offset + Point(0, param.top.se_a)));
336 }
337 return;
338 }
339 if (!reverse) {
340 AddOctant(param.top, /*reverse=*/false, /*flip=*/false, transform);
341 AddOctant(param.right, /*reverse=*/true, /*flip=*/true, transform);
342 } else {
343 AddOctant(param.right, /*reverse=*/false, /*flip=*/true, transform);
344 AddOctant(param.top, /*reverse=*/true, /*flip=*/false, transform);
345 }
346 }
347
348 private:
349 std::array<Point, 4> SuperellipseArcPoints(
350 const RoundSuperellipseParam::Octant& param) {
351 Point start = {0, param.se_a};
352 const Point& end = param.circle_start;
353 constexpr Point start_tangent = {1, 0};
354 Point circle_start_vector = param.circle_start - param.circle_center;
355 Point end_tangent =
356 Point{-circle_start_vector.y, circle_start_vector.x}.Normalize();
357
358 std::array<Scalar, 2> factors = SuperellipseBezierFactors(param.se_n);
359
360 return std::array<Point, 4>{
361 start, start + start_tangent * factors[0] * param.se_a,
362 end + end_tangent * factors[1] * param.se_a, end};
363 };
364
365 std::array<Point, 4> CircularArcPoints(
366 const RoundSuperellipseParam::Octant& param) {
367 Point start_vector = param.circle_start - param.circle_center;
368 Point end_vector =
369 start_vector.Rotate(Radians(-param.circle_max_angle.radians));
370 Point circle_end = param.circle_center + end_vector;
371 Point start_tangent = Point{start_vector.y, -start_vector.x}.Normalize();
372 Point end_tangent = Point{-end_vector.y, end_vector.x}.Normalize();
373 Scalar bezier_factor = std::tan(param.circle_max_angle.radians / 4) * 4 / 3;
374 Scalar radius = start_vector.GetLength();
375
376 return std::array<Point, 4>{
377 param.circle_start,
378 param.circle_start + start_tangent * bezier_factor * radius,
379 circle_end + end_tangent * bezier_factor * radius, circle_end};
380 };
381
382 // Draws an arc representing 1/8 of a rounded superellipse.
383 //
384 // If `reverse` is false, the resulting arc spans from 0 to pi/4, moving
385 // clockwise starting from the positive Y-axis. Otherwise it moves from pi/4
386 // to 0.
387 //
388 // If `flip` is true, all points have their X and Y coordinates swapped,
389 // effectively mirrowing each point by the y=x line.
390 //
391 // All points are transformed by `external_transform` after the optional
392 // flipping before being used as control points for the cubic curves.
393 void AddOctant(const RoundSuperellipseParam::Octant& param,
394 bool reverse,
395 bool flip,
396 const Matrix& external_transform) {
397 Matrix transform =
398 external_transform * Matrix::MakeTranslation(param.offset);
399 if (flip) {
400 transform = transform * kFlip;
401 }
402
403 auto circle_points = CircularArcPoints(param);
404 auto se_points = SuperellipseArcPoints(param);
405
406 if (!reverse) {
407 receiver_.CubicTo(transform * se_points[1], transform * se_points[2],
408 transform * se_points[3]);
409 receiver_.CubicTo(transform * circle_points[1],
410 transform * circle_points[2],
411 transform * circle_points[3]);
412 } else {
413 receiver_.CubicTo(transform * circle_points[2],
414 transform * circle_points[1],
415 transform * circle_points[0]);
416 receiver_.CubicTo(transform * se_points[2], transform * se_points[1],
417 transform * se_points[0]);
418 }
419 };
420
421 // Get the Bezier factor for the superellipse arc in a rounded superellipse.
422 //
423 // The result will be assigned to output, where [0] will be the factor for the
424 // starting tangent and [1] for the ending tangent.
425 //
426 // These values are computed by brute-force searching for the minimal distance
427 // on a rounded superellipse and are not for general purpose superellipses.
428 std::array<Scalar, 2> SuperellipseBezierFactors(Scalar n) {
429 constexpr Scalar kPrecomputedVariables[][2] = {
430 /*n=2.0*/ {0.01339448, 0.05994973},
431 /*n=3.0*/ {0.13664115, 0.13592082},
432 /*n=4.0*/ {0.24545546, 0.14099516},
433 /*n=5.0*/ {0.32353151, 0.12808021},
434 /*n=6.0*/ {0.39093068, 0.11726264},
435 /*n=7.0*/ {0.44847800, 0.10808278},
436 /*n=8.0*/ {0.49817452, 0.10026175},
437 /*n=9.0*/ {0.54105583, 0.09344429},
438 /*n=10.0*/ {0.57812578, 0.08748984},
439 /*n=11.0*/ {0.61050961, 0.08224722},
440 /*n=12.0*/ {0.63903989, 0.07759639},
441 /*n=13.0*/ {0.66416338, 0.07346530},
442 /*n=14.0*/ {0.68675338, 0.06974996},
443 /*n=15.0*/ {0.70678034, 0.06529512}};
444 constexpr size_t kNumRecords =
445 sizeof(kPrecomputedVariables) / sizeof(kPrecomputedVariables[0]);
446 constexpr Scalar kStep = 1.00f;
447 constexpr Scalar kMinN = 2.00f;
448 constexpr Scalar kMaxN = kMinN + (kNumRecords - 1) * kStep;
449
450 if (n >= kMaxN) {
451 // Heuristic formula derived from fitting.
452 return {1.07f - expf(1.307649835) * powf(n, -0.8568516731),
453 -0.01f + expf(-0.9287690322) * powf(n, -0.6120901398)};
454 }
455
456 Scalar steps = std::clamp<Scalar>((n - kMinN) / kStep, 0, kNumRecords - 1);
457 size_t left = std::clamp<size_t>(static_cast<size_t>(std::floor(steps)), 0,
458 kNumRecords - 2);
459 Scalar frac = steps - left;
460
461 return std::array<Scalar, 2>{(1 - frac) * kPrecomputedVariables[left][0] +
462 frac * kPrecomputedVariables[left + 1][0],
463 (1 - frac) * kPrecomputedVariables[left][1] +
464 frac * kPrecomputedVariables[left + 1][1]};
465 }
466
467 PathReceiver& receiver_;
468
469 // A matrix that swaps the coordinates of a point.
470 // clang-format off
471 static constexpr Matrix kFlip = Matrix(
472 0.0f, 1.0f, 0.0f, 0.0f,
473 1.0f, 0.0f, 0.0f, 0.0f,
474 0.0f, 0.0f, 1.0f, 0.0f,
475 0.0f, 0.0f, 0.0f, 1.0f);
476 // clang-format on
477 };
478
479 } // namespace
480
481 RoundSuperellipseParam RoundSuperellipseParam::MakeBoundsRadius(
482 const Rect& bounds,
483 Scalar radius) {
484 return RoundSuperellipseParam{
485 .top_right = ComputeQuadrant(bounds.GetCenter(), bounds.GetRightTop(),
486 {radius, radius}, {-1, 1}),
487 .all_corners_same = true,
488 };
489 }
490
491 RoundSuperellipseParam RoundSuperellipseParam::MakeBoundsRadii(
492 const Rect& bounds,
493 const RoundingRadii& radii) {
494 if (radii.AreAllCornersSame() && !radii.top_left.IsEmpty()) {
495 // Having four empty corners indicate a rectangle, which needs special
496 // treatment on border containment and therefore is not `all_corners_same`.
497 return RoundSuperellipseParam{
498 .top_right = ComputeQuadrant(bounds.GetCenter(), bounds.GetRightTop(),
499 radii.top_right, {-1, 1}),
500 .all_corners_same = true,
501 };
502 }
503 Scalar top_split = Split(bounds.GetLeft(), bounds.GetRight(),
504 radii.top_left.width, radii.top_right.width);
505 Scalar right_split = Split(bounds.GetTop(), bounds.GetBottom(),
506 radii.top_right.height, radii.bottom_right.height);
507 Scalar bottom_split =
508 Split(bounds.GetLeft(), bounds.GetRight(), radii.bottom_left.width,
509 radii.bottom_right.width);
510 Scalar left_split = Split(bounds.GetTop(), bounds.GetBottom(),
511 radii.top_left.height, radii.bottom_left.height);
512
513 return RoundSuperellipseParam{
514 .top_right =
515 ComputeQuadrant(Point{top_split, right_split}, bounds.GetRightTop(),
516 radii.top_right, {1, -1}),
517 .bottom_right =
518 ComputeQuadrant(Point{bottom_split, right_split},
519 bounds.GetRightBottom(), radii.bottom_right, {1, 1}),
520 .bottom_left =
521 ComputeQuadrant(Point{bottom_split, left_split},
522 bounds.GetLeftBottom(), radii.bottom_left, {-1, 1}),
523 .top_left =
524 ComputeQuadrant(Point{top_split, left_split}, bounds.GetLeftTop(),
525 radii.top_left, {-1, -1}),
526 .all_corners_same = false,
527 };
528 }
529
530 void RoundSuperellipseParam::Dispatch(PathReceiver& path_receiver) const {
531 RoundSuperellipseBuilder builder(path_receiver);
532
533 Point start = top_right.offset +
534 top_right.signed_scale *
535 (top_right.top.offset + Point(0, top_right.top.se_a));
536 path_receiver.MoveTo(start, true);
537
538 if (all_corners_same) {
539 builder.AddQuadrant(top_right, /*reverse=*/false, Point(1, 1));
540 builder.AddQuadrant(top_right, /*reverse=*/true, Point(1, -1));
541 builder.AddQuadrant(top_right, /*reverse=*/false, Point(-1, -1));
542 builder.AddQuadrant(top_right, /*reverse=*/true, Point(-1, 1));
543 } else {
544 builder.AddQuadrant(top_right, /*reverse=*/false);
545 builder.AddQuadrant(bottom_right, /*reverse=*/true);
546 builder.AddQuadrant(bottom_left, /*reverse=*/false);
547 builder.AddQuadrant(top_left, /*reverse=*/true);
548 }
549
550 path_receiver.LineTo(start);
551 path_receiver.Close();
552 }
553
554 bool RoundSuperellipseParam::Contains(const Point& point) const {
555 if (all_corners_same) {
556 return CornerContains(top_right, point, /*check_quadrant=*/false);
557 }
558 return CornerContains(top_right, point) &&
559 CornerContains(bottom_right, point) &&
560 CornerContains(bottom_left, point) && CornerContains(top_left, point);
561 }
562
563 } // 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::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:57
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:491
impeller::RoundSuperellipseParam::Dispatch
void Dispatch(PathReceiver &receiver) const
Definition: round_superellipse_param.cc:530
impeller::RoundSuperellipseParam::Contains
bool Contains(const Point &point) const
Definition: round_superellipse_param.cc:554
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:481
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::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