/* * Copyright 2011 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ // Unit tests for src/core/SkPoint.cpp and its header #include "SkPointPriv.h" #include "SkRect.h" #include "Test.h" static void test_casts(skiatest::Reporter* reporter) { SkPoint p = { 0, 0 }; SkRect r = { 0, 0, 0, 0 }; const SkScalar* pPtr = SkTCast<const SkScalar*>(&p); const SkScalar* rPtr = SkTCast<const SkScalar*>(&r); REPORTER_ASSERT(reporter, SkPointPriv::AsScalars(p) == pPtr); REPORTER_ASSERT(reporter, r.asScalars() == rPtr); } // Tests SkPoint::Normalize() for this (x,y) static void test_Normalize(skiatest::Reporter* reporter, SkScalar x, SkScalar y) { SkPoint point; point.set(x, y); SkScalar oldLength = point.length(); SkScalar returned = SkPoint::Normalize(&point); SkScalar newLength = point.length(); REPORTER_ASSERT(reporter, SkScalarNearlyEqual(returned, oldLength)); REPORTER_ASSERT(reporter, SkScalarNearlyEqual(newLength, SK_Scalar1)); } // Tests that SkPoint::length() and SkPoint::Length() both return // approximately expectedLength for this (x,y). static void test_length(skiatest::Reporter* reporter, SkScalar x, SkScalar y, SkScalar expectedLength) { SkPoint point; point.set(x, y); SkScalar s1 = point.length(); SkScalar s2 = SkPoint::Length(x, y); //The following should be exactly the same, but need not be. //See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, s2)); REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, expectedLength)); test_Normalize(reporter, x, y); } // Ugh. Windows compiler can dive into other .cpp files, and sometimes // notices that I will generate an overflow... which is exactly the point // of this test! // // To avoid this warning, I need to convince the compiler that I might not // use that big value, hence this hacky helper function: reporter is // ALWAYS non-null. (shhhhhh, don't tell the compiler that). template <typename T> T get_value(skiatest::Reporter* reporter, T value) { return reporter ? value : 0; } // On linux gcc, 32bit, we are seeing the compiler propagate up the value // of SkPoint::length() as a double (which we use sometimes to avoid overflow // during the computation), even though the signature says float (SkScalar). // // force_as_float is meant to capture our latest technique (horrible as // it is) to force the value to be a float, so we can test whether it was // finite or not. static float force_as_float(skiatest::Reporter* reporter, float value) { uint32_t storage; memcpy(&storage, &value, 4); // even the pair of memcpy calls are not sufficient, since those seem to // be no-op'd, so we add a runtime tests (just like get_value) to force // the compiler to give us an actual float. if (nullptr == reporter) { storage = ~storage; } memcpy(&value, &storage, 4); return value; } // test that we handle very large values correctly. i.e. that we can // successfully normalize something whose mag overflows a float. static void test_overflow(skiatest::Reporter* reporter) { SkScalar bigFloat = get_value(reporter, 3.4e38f); SkPoint pt = { bigFloat, bigFloat }; SkScalar length = pt.length(); length = force_as_float(reporter, length); // expect this to be non-finite, but dump the results if not. if (SkScalarIsFinite(length)) { SkDebugf("length(%g, %g) == %g\n", pt.fX, pt.fY, length); REPORTER_ASSERT(reporter, !SkScalarIsFinite(length)); } // this should succeed, even though we can't represent length REPORTER_ASSERT(reporter, pt.setLength(SK_Scalar1)); // now that pt is normalized, we check its length length = pt.length(); REPORTER_ASSERT(reporter, SkScalarNearlyEqual(length, SK_Scalar1)); } // test that we handle very small values correctly. i.e. that we can // report failure if we try to normalize them. static void test_underflow(skiatest::Reporter* reporter) { SkPoint pt = { 1.0e-37f, 1.0e-37f }; const SkPoint empty = { 0, 0 }; REPORTER_ASSERT(reporter, 0 == SkPoint::Normalize(&pt)); REPORTER_ASSERT(reporter, pt == empty); REPORTER_ASSERT(reporter, !pt.setLength(SK_Scalar1)); REPORTER_ASSERT(reporter, pt == empty); } DEF_TEST(Point, reporter) { test_casts(reporter); static const struct { SkScalar fX; SkScalar fY; SkScalar fLength; } gRec[] = { { SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5) }, { 0.6f, 0.8f, SK_Scalar1 }, }; for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) { test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength); } test_underflow(reporter); test_overflow(reporter); } DEF_TEST(Point_setLengthFast, reporter) { // Scale a (1,1) point to a bunch of different lengths, // making sure the slow and fast paths are within 0.1%. const float tests[] = { 1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f }; const SkPoint kOne = {1.0f, 1.0f}; for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) { SkPoint slow = kOne, fast = kOne; slow.setLength(tests[i]); SkPointPriv::SetLengthFast(&fast, tests[i]); if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue; SkScalar ratio = slow.length() / fast.length(); REPORTER_ASSERT(reporter, ratio > 0.999f); REPORTER_ASSERT(reporter, ratio < 1.001f); } }