1 /* 2 * Copyright 2011 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 // Unit tests for src/core/SkPoint.cpp and its header 8 9 #include "SkPointPriv.h" 10 #include "SkRect.h" 11 #include "Test.h" 12 13 static void test_casts(skiatest::Reporter* reporter) { 14 SkPoint p = { 0, 0 }; 15 SkRect r = { 0, 0, 0, 0 }; 16 17 const SkScalar* pPtr = reinterpret_cast<const SkScalar*>(&p); 18 const SkScalar* rPtr = reinterpret_cast<const SkScalar*>(&r); 19 20 REPORTER_ASSERT(reporter, SkPointPriv::AsScalars(p) == pPtr); 21 REPORTER_ASSERT(reporter, r.asScalars() == rPtr); 22 } 23 24 // Tests SkPoint::Normalize() for this (x,y) 25 static void test_Normalize(skiatest::Reporter* reporter, 26 SkScalar x, SkScalar y) { 27 SkPoint point; 28 point.set(x, y); 29 SkScalar oldLength = point.length(); 30 SkScalar returned = SkPoint::Normalize(&point); 31 SkScalar newLength = point.length(); 32 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(returned, oldLength)); 33 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(newLength, SK_Scalar1)); 34 } 35 36 static void test_normalize_cannormalize_consistent(skiatest::Reporter* reporter) { 37 const SkScalar values[] = { 1, 1e18f, 1e20f, 1e38f, SK_ScalarInfinity, SK_ScalarNaN }; 38 39 for (SkScalar val : values) { 40 const SkScalar variants[] = { val, -val, SkScalarInvert(val), -SkScalarInvert(val) }; 41 42 for (SkScalar v : variants) { 43 const SkPoint pts[] = { { 0, v }, { v, 0 }, { 1, v }, { v, 1 }, { v, v } }; 44 45 for (SkPoint p : pts) { 46 bool can = SkPointPriv::CanNormalize(p.fX, p.fY); 47 bool nor = p.normalize(); 48 REPORTER_ASSERT(reporter, can == nor); 49 } 50 } 51 } 52 } 53 54 // Tests that SkPoint::length() and SkPoint::Length() both return 55 // approximately expectedLength for this (x,y). 56 static void test_length(skiatest::Reporter* reporter, SkScalar x, SkScalar y, 57 SkScalar expectedLength) { 58 SkPoint point; 59 point.set(x, y); 60 SkScalar s1 = point.length(); 61 SkScalar s2 = SkPoint::Length(x, y); 62 //The following should be exactly the same, but need not be. 63 //See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 64 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, s2)); 65 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, expectedLength)); 66 67 test_Normalize(reporter, x, y); 68 } 69 70 // Ugh. Windows compiler can dive into other .cpp files, and sometimes 71 // notices that I will generate an overflow... which is exactly the point 72 // of this test! 73 // 74 // To avoid this warning, I need to convince the compiler that I might not 75 // use that big value, hence this hacky helper function: reporter is 76 // ALWAYS non-null. (shhhhhh, don't tell the compiler that). 77 template <typename T> T get_value(skiatest::Reporter* reporter, T value) { 78 return reporter ? value : 0; 79 } 80 81 // On linux gcc, 32bit, we are seeing the compiler propagate up the value 82 // of SkPoint::length() as a double (which we use sometimes to avoid overflow 83 // during the computation), even though the signature says float (SkScalar). 84 // 85 // force_as_float is meant to capture our latest technique (horrible as 86 // it is) to force the value to be a float, so we can test whether it was 87 // finite or not. 88 static float force_as_float(skiatest::Reporter* reporter, float value) { 89 uint32_t storage; 90 memcpy(&storage, &value, 4); 91 // even the pair of memcpy calls are not sufficient, since those seem to 92 // be no-op'd, so we add a runtime tests (just like get_value) to force 93 // the compiler to give us an actual float. 94 if (nullptr == reporter) { 95 storage = ~storage; 96 } 97 memcpy(&value, &storage, 4); 98 return value; 99 } 100 101 // test that we handle very large values correctly. i.e. that we can 102 // successfully normalize something whose mag overflows a float. 103 static void test_overflow(skiatest::Reporter* reporter) { 104 SkScalar bigFloat = get_value(reporter, 3.4e38f); 105 SkPoint pt = { bigFloat, bigFloat }; 106 107 SkScalar length = pt.length(); 108 length = force_as_float(reporter, length); 109 110 // expect this to be non-finite, but dump the results if not. 111 if (SkScalarIsFinite(length)) { 112 SkDebugf("length(%g, %g) == %g\n", pt.fX, pt.fY, length); 113 REPORTER_ASSERT(reporter, !SkScalarIsFinite(length)); 114 } 115 116 // this should succeed, even though we can't represent length 117 REPORTER_ASSERT(reporter, pt.setLength(SK_Scalar1)); 118 119 // now that pt is normalized, we check its length 120 length = pt.length(); 121 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(length, SK_Scalar1)); 122 } 123 124 DEF_TEST(Point, reporter) { 125 test_casts(reporter); 126 127 static const struct { 128 SkScalar fX; 129 SkScalar fY; 130 SkScalar fLength; 131 } gRec[] = { 132 { SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5) }, 133 { 0.6f, 0.8f, SK_Scalar1 }, 134 }; 135 136 for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) { 137 test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength); 138 } 139 140 test_overflow(reporter); 141 test_normalize_cannormalize_consistent(reporter); 142 } 143 144 DEF_TEST(Point_setLengthFast, reporter) { 145 // Scale a (1,1) point to a bunch of different lengths, 146 // making sure the slow and fast paths are within 0.1%. 147 const float tests[] = { 1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f }; 148 149 const SkPoint kOne = {1.0f, 1.0f}; 150 for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) { 151 SkPoint slow = kOne, fast = kOne; 152 153 slow.setLength(tests[i]); 154 SkPointPriv::SetLengthFast(&fast, tests[i]); 155 156 if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue; 157 158 SkScalar ratio = slow.length() / fast.length(); 159 REPORTER_ASSERT(reporter, ratio > 0.999f); 160 REPORTER_ASSERT(reporter, ratio < 1.001f); 161 } 162 } 163
