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
62 lines
2.2 KiB
C++
62 lines
2.2 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 "SkIntersections.h"
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#include "SkPathOpsCubic.h"
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#include "SkPathOpsLine.h"
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#include "SkReduceOrder.h"
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#include "Test.h"
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static struct lineCubic {
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SkDCubic cubic;
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SkDLine line;
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} lineCubicTests[] = {
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{{{{1, 2}, {2, 6}, {2, 0}, {1, 0}}}, {{{1, 0}, {1, 2}}}},
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{{{{0, 0}, {0, 1}, {0, 1}, {1, 1}}}, {{{0, 1}, {1, 0}}}},
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};
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static const size_t lineCubicTests_count = sizeof(lineCubicTests) / sizeof(lineCubicTests[0]);
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static void CubicLineIntersectionTest(skiatest::Reporter* reporter) {
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for (size_t index = 0; index < lineCubicTests_count; ++index) {
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int iIndex = static_cast<int>(index);
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const SkDCubic& cubic = lineCubicTests[index].cubic;
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const SkDLine& line = lineCubicTests[index].line;
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SkReduceOrder reduce1;
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SkReduceOrder reduce2;
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int order1 = reduce1.reduce(cubic, SkReduceOrder::kNo_Quadratics,
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SkReduceOrder::kFill_Style);
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int order2 = reduce2.reduce(line);
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if (order1 < 4) {
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SkDebugf("[%d] cubic order=%d\n", iIndex, order1);
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REPORTER_ASSERT(reporter, 0);
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}
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if (order2 < 2) {
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SkDebugf("[%d] line order=%d\n", iIndex, order2);
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REPORTER_ASSERT(reporter, 0);
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}
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if (order1 == 4 && order2 == 2) {
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SkIntersections i;
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int roots = i.intersect(cubic, line);
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for (int pt = 0; pt < roots; ++pt) {
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double tt1 = i[0][pt];
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SkDPoint xy1 = cubic.xyAtT(tt1);
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double tt2 = i[1][pt];
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SkDPoint xy2 = line.xyAtT(tt2);
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if (!xy1.approximatelyEqual(xy2)) {
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SkDebugf("%s [%d,%d] x!= t1=%g (%g,%g) t2=%g (%g,%g)\n",
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__FUNCTION__, iIndex, pt, tt1, xy1.fX, xy1.fY, tt2, xy2.fX, xy2.fY);
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}
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REPORTER_ASSERT(reporter, xy1.approximatelyEqual(xy2));
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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("PathOpsCubicLineIntersection", CubicLineIntersectionTestClass, \
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CubicLineIntersectionTest)
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