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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 "include/core/SkCubicMap.h"
- #include "include/core/SkPoint.h"
- #include "include/core/SkScalar.h"
- #include "include/core/SkTypes.h"
- #include "include/private/SkNx.h"
- #include "src/core/SkGeometry.h"
- #include "src/pathops/SkPathOpsCubic.h"
- #include "tests/Test.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 (!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);
- }
- }
- }
- }
- }
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