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 /* * 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 "SkGeometry.h" #include "SkRandom.h" #include "Test.h" #include "../../src/pathops/SkPathOpsCubic.h" static float accurate_t(float A, float B, float C, float D) { double roots[3]; SkDEBUGCODE(int count =) SkDCubic::RootsValidT(A, B, C, D, roots); SkASSERT(count == 1); return (float)roots[0]; } static float accurate_solve(SkPoint p1, SkPoint p2, SkScalar x) { SkPoint array[] = { {0, 0}, p1, p2, {1,1} }; SkCubicCoeff coeff(array); float t = accurate_t(coeff.fA[0], coeff.fB[0], coeff.fC[0], coeff.fD[0] - x); SkASSERT(t >= 0 && t <= 1); float y = coeff.eval(t)[1]; SkASSERT(y >= 0 && y <= 1.0001f); return y; } static bool nearly_le(SkScalar a, SkScalar b) { return a <= b || SkScalarNearlyZero(a - b); } static void exercise_cubicmap(SkPoint p1, SkPoint p2, skiatest::Reporter* reporter) { const SkScalar MAX_SOLVER_ERR = 0.008f; // found by running w/ current impl SkCubicMap cmap(p1, p2); SkScalar prev_y = 0; SkScalar dx = 1.0f / 512; for (SkScalar x = dx; x < 1; x += dx) { SkScalar y = cmap.computeYFromX(x); // are we valid and (mostly) monotonic? if (y < 0 || y > 1 || !nearly_le(prev_y, y)) { cmap.computeYFromX(x); REPORTER_ASSERT(reporter, false); } prev_y = y; // are we close to the "correct" answer? SkScalar yy = accurate_solve(p1, p2, x); SkScalar diff = SkScalarAbs(yy - y); REPORTER_ASSERT(reporter, diff < MAX_SOLVER_ERR); } } DEF_TEST(CubicMap, r) { const SkScalar values[] = { 0, 1, 0.5f, 0.0000001f, 0.999999f, }; for (SkScalar x0 : values) { for (SkScalar y0 : values) { for (SkScalar x1 : values) { for (SkScalar y1 : values) { exercise_cubicmap({ x0, y0 }, { x1, y1 }, r); } } } } }