| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkCubicMap.h" |
| #include "SkNx.h" |
| #include "../../src/pathops/SkPathOpsCubic.h" |
| |
| void SkCubicMap::setPts(SkPoint p1, SkPoint p2) { |
| Sk2s s1 = Sk2s::Load(&p1) * 3; |
| Sk2s s2 = Sk2s::Load(&p2) * 3; |
| |
| s1 = Sk2s::Min(Sk2s::Max(s1, 0), 3); |
| s2 = Sk2s::Min(Sk2s::Max(s2, 0), 3); |
| |
| (Sk2s(1) + s1 - s2).store(&fCoeff[0]); |
| (s2 - s1 - s1).store(&fCoeff[1]); |
| s1.store(&fCoeff[2]); |
| |
| this->buildXTable(); |
| } |
| |
| SkPoint SkCubicMap::computeFromT(float t) const { |
| Sk2s a = Sk2s::Load(&fCoeff[0]); |
| Sk2s b = Sk2s::Load(&fCoeff[1]); |
| Sk2s c = Sk2s::Load(&fCoeff[2]); |
| |
| SkPoint result; |
| (((a * t + b) * t + c) * t).store(&result); |
| return result; |
| } |
| |
| float SkCubicMap::computeYFromX(float x) const { |
| x = SkTPin<float>(x, 0, 0.99999f) * kTableCount; |
| float ix = sk_float_floor(x); |
| int index = (int)ix; |
| SkASSERT((unsigned)index < SK_ARRAY_COUNT(fXTable)); |
| return this->computeFromT(fXTable[index].fT0 + fXTable[index].fDT * (x - ix)).fY; |
| } |
| |
| float SkCubicMap::hackYFromX(float x) const { |
| x = SkTPin<float>(x, 0, 0.99999f) * kTableCount; |
| float ix = sk_float_floor(x); |
| int index = (int)ix; |
| SkASSERT((unsigned)index < SK_ARRAY_COUNT(fXTable)); |
| return fXTable[index].fY0 + fXTable[index].fDY * (x - ix); |
| } |
| |
| static float compute_t_from_x(float A, float B, float C, float x) { |
| double roots[3]; |
| SkDEBUGCODE(int count =) SkDCubic::RootsValidT(A, B, C, -x, roots); |
| SkASSERT(count == 1); |
| return (float)roots[0]; |
| } |
| |
| void SkCubicMap::buildXTable() { |
| float prevT = 0; |
| |
| const float dx = 1.0f / kTableCount; |
| float x = dx; |
| |
| fXTable[0].fT0 = 0; |
| fXTable[0].fY0 = 0; |
| for (int i = 1; i < kTableCount; ++i) { |
| float t = compute_t_from_x(fCoeff[0].fX, fCoeff[1].fX, fCoeff[2].fX, x); |
| SkASSERT(t > prevT); |
| |
| fXTable[i - 1].fDT = t - prevT; |
| fXTable[i].fT0 = t; |
| |
| SkPoint p = this->computeFromT(t); |
| fXTable[i - 1].fDY = p.fY - fXTable[i - 1].fY0; |
| fXTable[i].fY0 = p.fY; |
| |
| prevT = t; |
| x += dx; |
| } |
| fXTable[kTableCount - 1].fDT = 1 - prevT; |
| fXTable[kTableCount - 1].fDY = 1 - fXTable[kTableCount - 1].fY0; |
| } |