1 2 /* 3 * Copyright 2011 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 // Unit tests for src/core/SkPoint.cpp and its header 9 10 #include "SkPoint.h" 11 #include "SkRect.h" 12 #include "Test.h" 13 14 static void test_casts(skiatest::Reporter* reporter) { 15 SkPoint p = { 0, 0 }; 16 SkRect r = { 0, 0, 0, 0 }; 17 18 const SkScalar* pPtr = SkTCast<const SkScalar*>(&p); 19 const SkScalar* rPtr = SkTCast<const SkScalar*>(&r); 20 21 REPORTER_ASSERT(reporter, p.asScalars() == pPtr); 22 REPORTER_ASSERT(reporter, r.asScalars() == rPtr); 23 } 24 25 // Tests SkPoint::Normalize() for this (x,y) 26 static void test_Normalize(skiatest::Reporter* reporter, 27 SkScalar x, SkScalar y) { 28 SkPoint point; 29 point.set(x, y); 30 SkScalar oldLength = point.length(); 31 SkScalar returned = SkPoint::Normalize(&point); 32 SkScalar newLength = point.length(); 33 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(returned, oldLength)); 34 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(newLength, SK_Scalar1)); 35 } 36 37 // Tests that SkPoint::length() and SkPoint::Length() both return 38 // approximately expectedLength for this (x,y). 39 static void test_length(skiatest::Reporter* reporter, SkScalar x, SkScalar y, 40 SkScalar expectedLength) { 41 SkPoint point; 42 point.set(x, y); 43 SkScalar s1 = point.length(); 44 SkScalar s2 = SkPoint::Length(x, y); 45 //The following should be exactly the same, but need not be. 46 //See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 47 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, s2)); 48 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, expectedLength)); 49 50 test_Normalize(reporter, x, y); 51 } 52 53 // Ugh. Windows compiler can dive into other .cpp files, and sometimes 54 // notices that I will generate an overflow... which is exactly the point 55 // of this test! 56 // 57 // To avoid this warning, I need to convince the compiler that I might not 58 // use that big value, hence this hacky helper function: reporter is 59 // ALWAYS non-null. (shhhhhh, don't tell the compiler that). 60 template <typename T> T get_value(skiatest::Reporter* reporter, T value) { 61 return reporter ? value : 0; 62 } 63 64 // On linux gcc, 32bit, we are seeing the compiler propagate up the value 65 // of SkPoint::length() as a double (which we use sometimes to avoid overflow 66 // during the computation), even though the signature says float (SkScalar). 67 // 68 // force_as_float is meant to capture our latest technique (horrible as 69 // it is) to force the value to be a float, so we can test whether it was 70 // finite or not. 71 static float force_as_float(skiatest::Reporter* reporter, float value) { 72 uint32_t storage; 73 memcpy(&storage, &value, 4); 74 // even the pair of memcpy calls are not sufficient, since those seem to 75 // be no-op'd, so we add a runtime tests (just like get_value) to force 76 // the compiler to give us an actual float. 77 if (nullptr == reporter) { 78 storage = ~storage; 79 } 80 memcpy(&value, &storage, 4); 81 return value; 82 } 83 84 // test that we handle very large values correctly. i.e. that we can 85 // successfully normalize something whose mag overflows a float. 86 static void test_overflow(skiatest::Reporter* reporter) { 87 SkScalar bigFloat = get_value(reporter, 3.4e38f); 88 SkPoint pt = { bigFloat, bigFloat }; 89 90 SkScalar length = pt.length(); 91 length = force_as_float(reporter, length); 92 93 // expect this to be non-finite, but dump the results if not. 94 if (SkScalarIsFinite(length)) { 95 SkDebugf("length(%g, %g) == %g\n", pt.fX, pt.fY, length); 96 REPORTER_ASSERT(reporter, !SkScalarIsFinite(length)); 97 } 98 99 // this should succeed, even though we can't represent length 100 REPORTER_ASSERT(reporter, pt.setLength(SK_Scalar1)); 101 102 // now that pt is normalized, we check its length 103 length = pt.length(); 104 REPORTER_ASSERT(reporter, SkScalarNearlyEqual(length, SK_Scalar1)); 105 } 106 107 // test that we handle very small values correctly. i.e. that we can 108 // report failure if we try to normalize them. 109 static void test_underflow(skiatest::Reporter* reporter) { 110 SkPoint pt = { 1.0e-37f, 1.0e-37f }; 111 const SkPoint empty = { 0, 0 }; 112 113 REPORTER_ASSERT(reporter, 0 == SkPoint::Normalize(&pt)); 114 REPORTER_ASSERT(reporter, pt == empty); 115 116 REPORTER_ASSERT(reporter, !pt.setLength(SK_Scalar1)); 117 REPORTER_ASSERT(reporter, pt == empty); 118 } 119 120 DEF_TEST(Point, reporter) { 121 test_casts(reporter); 122 123 static const struct { 124 SkScalar fX; 125 SkScalar fY; 126 SkScalar fLength; 127 } gRec[] = { 128 { SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5) }, 129 { 0.6f, 0.8f, SK_Scalar1 }, 130 }; 131 132 for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) { 133 test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength); 134 } 135 136 test_underflow(reporter); 137 test_overflow(reporter); 138 } 139 140 DEF_TEST(Point_setLengthFast, reporter) { 141 // Scale a (1,1) point to a bunch of different lengths, 142 // making sure the slow and fast paths are within 0.1%. 143 const float tests[] = { 1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f }; 144 145 const SkPoint kOne = {1.0f, 1.0f}; 146 for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) { 147 SkPoint slow = kOne, fast = kOne; 148 149 slow.setLength(tests[i]); 150 fast.setLengthFast(tests[i]); 151 152 if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue; 153 154 SkScalar ratio = slow.length() / fast.length(); 155 REPORTER_ASSERT(reporter, ratio > 0.999f); 156 REPORTER_ASSERT(reporter, ratio < 1.001f); 157 } 158 } 159
