9166dcb3a0
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
54 lines
1.9 KiB
C++
54 lines
1.9 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkDQuadImplicit.h"
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#include "SkPathOpsQuad.h"
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#include "Test.h"
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static bool point_on_parameterized_curve(const SkDQuad& quad, const SkDPoint& point) {
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SkDQuadImplicit q(quad);
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double xx = q.x2() * point.fX * point.fX;
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double xy = q.xy() * point.fX * point.fY;
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double yy = q.y2() * point.fY * point.fY;
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double x = q.x() * point.fX;
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double y = q.y() * point.fY;
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double c = q.c();
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double sum = xx + xy + yy + x + y + c;
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return approximately_zero(sum);
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}
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static const SkDQuad quadratics[] = {
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{{{0, 0}, {1, 0}, {1, 1}}},
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};
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static const size_t quadratics_count = sizeof(quadratics) / sizeof(quadratics[0]);
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static void TestQuadraticCoincidence(skiatest::Reporter* reporter) {
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// split large quadratic
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// compare original, parts, to see if the are coincident
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for (size_t index = 0; index < quadratics_count; ++index) {
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const SkDQuad& test = quadratics[index];
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SkDQuadPair split = test.chopAt(0.5);
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SkDQuad midThird = test.subDivide(1.0/3, 2.0/3);
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const SkDQuad* quads[] = {
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&test, &midThird, &split.first(), &split.second()
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};
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size_t quadsCount = sizeof(quads) / sizeof(quads[0]);
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for (size_t one = 0; one < quadsCount; ++one) {
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for (size_t two = 0; two < quadsCount; ++two) {
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for (size_t inner = 0; inner < 3; inner += 2) {
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REPORTER_ASSERT(reporter, point_on_parameterized_curve(*quads[one],
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(*quads[two])[inner]));
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}
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REPORTER_ASSERT(reporter, SkDQuadImplicit::Match(*quads[one], *quads[two]));
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}
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}
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}
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}
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#include "TestClassDef.h"
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DEFINE_TESTCLASS("PathOpsQuadImplicit", QuadImplicitTestClass, TestQuadraticCoincidence)
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