skia2/tests/PathOpsLineIntersectionTest.cpp
caryclark@google.com 9166dcb3a0 Add intersections for path ops
This CL depends on 
https://codereview.chromium.org/12827020/
"Add base types for path ops"

The intersection of a line, quadratic, or cubic
with another curve (or with itself) is found by
solving the implicit equation for the curve pair.

The curves are first reduced to find the simplest
form that will describe the original, and to detect
degenerate or special-case data like horizontal and
vertical lines.

For cubic self-intersection, and for a pair of cubics,
the intersection is found by recursively
approximating the cubic with a series of quadratics.

The implicit solutions depend on the root finding
contained in the DCubic and DQuad structs, and
the quartic root finder included here.
Review URL: https://codereview.chromium.org/12880016

git-svn-id: http://skia.googlecode.com/svn/trunk@8552 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-08 11:50:00 +00:00

62 lines
2.3 KiB
C++

/*
* 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)