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