Add intersections for path ops

tests/PathOpsLineIntersectionTest.cpp

Index: tests/PathOpsLineIntersectionTest.cpp
===================================================================
--- tests/PathOpsLineIntersectionTest.cpp	(revision 0)
+++ tests/PathOpsLineIntersectionTest.cpp	(revision 0)
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkIntersections.h"
+#include "SkPathOpsLine.h"
+#include "Test.h"
+
+// FIXME: add tests for intersecting, non-intersecting, degenerate, coincident
+static const SkDLine tests[][2] = {
+    {{{{0, 0}, {1, 0}}}, {{{1, 0}, {0, 0}}}},
+    {{{{0, 0}, {0, 0}}}, {{{0, 0}, {1, 0}}}},
+    {{{{0, 1}, {0, 1}}}, {{{0, 0}, {0, 2}}}},
+    {{{{0, 0}, {1, 0}}}, {{{0, 0}, {2, 0}}}},
+    {{{{1, 1}, {2, 2}}}, {{{0, 0}, {3, 3}}}},
+    {{{{166.86950047022856, 112.69654129527828}, {166.86948801592692, 112.69655741235339}}},
+     {{{166.86960700313026, 112.6965477747386}, {166.86925794355412, 112.69656471103423}}}}
+};
+
+static const size_t tests_count = sizeof(tests) / sizeof(tests[0]);
+
+static const SkDLine noIntersect[][2] = {
+    {{{{0, 0}, {1, 0}}}, {{{3, 0}, {2, 0}}}},
+    {{{{0, 0}, {0, 0}}}, {{{1, 0}, {2, 0}}}},
+    {{{{0, 1}, {0, 1}}}, {{{0, 3}, {0, 2}}}},
+    {{{{0, 0}, {1, 0}}}, {{{2, 0}, {3, 0}}}},
+    {{{{1, 1}, {2, 2}}}, {{{4, 4}, {3, 3}}}},
+};
+
+static const size_t noIntersect_count = sizeof(noIntersect) / sizeof(noIntersect[0]);
+
+static void TestLineIntersection(skiatest::Reporter* reporter) {
+    size_t index;
+    for (index = 0; index < tests_count; ++index) {
+        const SkDLine& line1 = tests[index][0];
+        const SkDLine& line2 = tests[index][1];
+        SkIntersections ts;
+        int pts = ts.intersect(line1, line2);
+        REPORTER_ASSERT(reporter, pts);
+        for (int i = 0; i < pts; ++i) {
+            SkDPoint result1 = line1.xyAtT(ts[0][i]);
+            SkDPoint result2 = line2.xyAtT(ts[1][i]);
+            if (!result1.approximatelyEqual(result2)) {
+                REPORTER_ASSERT(reporter, pts != 1);
+                result2 = line2.xyAtT(ts[1][i ^ 1]);
+                REPORTER_ASSERT(reporter, result1.approximatelyEqual(result2));
+            }
+        }
+    }
+    for (index = 0; index < noIntersect_count; ++index) {
+        const SkDLine& line1 = noIntersect[index][0];
+        const SkDLine& line2 = noIntersect[index][1];
+        SkIntersections ts;
+        int pts = ts.intersect(line1, line2);
+        REPORTER_ASSERT(reporter, !pts);    }
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("PathOpsLineIntersection", LineIntersectionTestClass, TestLineIntersection)