| /* |
| * 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/base/SkDebug.h" |
| #include "src/base/SkCubics.h" |
| #include "src/base/SkVx.h" |
| #include "src/core/SkGeometry.h" |
| #include "tests/Test.h" |
| |
| static float accurate_t(float A, float B, float C, float D) { |
| double roots[3]; |
| SkDEBUGCODE(int count =) SkCubics::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); |
| } |
| } |
| } |
| } |
| } |