4db18edb95
Performs inset and outset operations on simple polygons and returns a simple polygon, if possible. Bug: skia: Change-Id: I6d468174ad70b5279b736c532e19cbb84ff9f955 Reviewed-on: https://skia-review.googlesource.com/116483 Commit-Queue: Jim Van Verth <jvanverth@google.com> Reviewed-by: Robert Phillips <robertphillips@google.com>
211 lines
9.1 KiB
C++
211 lines
9.1 KiB
C++
/*
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* Copyright 2017 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 "Test.h"
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#include "SkOffsetPolygon.h"
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static bool is_convex(const SkTDArray<SkPoint>& poly) {
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if (poly.count() < 3) {
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return false;
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}
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SkVector v0 = poly[0] - poly[poly.count() - 1];
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SkVector v1 = poly[1] - poly[poly.count() - 1];
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SkScalar winding = v0.cross(v1);
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for (int i = 0; i < poly.count()-1; ++i) {
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int j = i + 1;
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int k = (i + 2) % poly.count();
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SkVector v0 = poly[j] - poly[i];
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SkVector v1 = poly[k] - poly[i];
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SkScalar perpDot = v0.cross(v1);
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if (winding*perpDot < 0) {
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return false;
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}
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}
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return true;
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}
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DEF_TEST(OffsetSimplePoly, reporter) {
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SkTDArray<SkPoint> rrectPoly;
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///////////////////////////////////////////////////////////////////////
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// Try convex tests first
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// round rect
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*rrectPoly.push() = SkPoint::Make(-100, 55);
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*rrectPoly.push() = SkPoint::Make(100, 55);
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*rrectPoly.push() = SkPoint::Make(100 + 2.5f, 50 + 4.330127f);
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*rrectPoly.push() = SkPoint::Make(100 + 3.535534f, 50 + 3.535534f);
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*rrectPoly.push() = SkPoint::Make(100 + 4.330127f, 50 + 2.5f);
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*rrectPoly.push() = SkPoint::Make(105, 50);
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*rrectPoly.push() = SkPoint::Make(105, -50);
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*rrectPoly.push() = SkPoint::Make(100 + 4.330127f, -50 - 2.5f);
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*rrectPoly.push() = SkPoint::Make(100 + 3.535534f, -50 - 3.535534f);
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*rrectPoly.push() = SkPoint::Make(100 + 2.5f, -50 - 4.330127f);
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*rrectPoly.push() = SkPoint::Make(100, -55);
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*rrectPoly.push() = SkPoint::Make(-100, -55);
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*rrectPoly.push() = SkPoint::Make(-100 - 2.5f, -50 - 4.330127f);
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*rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, -50 - 3.535534f);
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*rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, -50 - 2.5f);
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*rrectPoly.push() = SkPoint::Make(-105, -50);
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*rrectPoly.push() = SkPoint::Make(-105, 50);
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*rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, 50 + 2.5f);
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*rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, 50 + 3.535534f);
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*rrectPoly.push() = SkPoint::Make(-100 - 2.5f, 50 + 4.330127f);
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REPORTER_ASSERT(reporter, is_convex(rrectPoly));
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// inset a little
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SkTDArray<SkPoint> offsetPoly;
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bool result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 3, &offsetPoly);
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REPORTER_ASSERT(reporter, result);
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REPORTER_ASSERT(reporter, is_convex(offsetPoly));
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// inset to rect
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result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 10, &offsetPoly);
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REPORTER_ASSERT(reporter, result);
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REPORTER_ASSERT(reporter, is_convex(offsetPoly));
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REPORTER_ASSERT(reporter, offsetPoly.count() == 4);
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if (offsetPoly.count() == 4) {
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REPORTER_ASSERT(reporter, offsetPoly[0].equals(-95, 45));
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REPORTER_ASSERT(reporter, offsetPoly[1].equals(95, 45));
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REPORTER_ASSERT(reporter, offsetPoly[2].equals(95, -45));
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REPORTER_ASSERT(reporter, offsetPoly[3].equals(-95, -45));
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}
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// just to full inset
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// fails, but outputs a line segment
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result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 55, &offsetPoly);
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REPORTER_ASSERT(reporter, !result);
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REPORTER_ASSERT(reporter, !is_convex(offsetPoly));
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REPORTER_ASSERT(reporter, offsetPoly.count() == 2);
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if (offsetPoly.count() == 2) {
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REPORTER_ASSERT(reporter, offsetPoly[0].equals(-50, 0));
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REPORTER_ASSERT(reporter, offsetPoly[1].equals(50, 0));
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}
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// past full inset
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result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 75, &offsetPoly);
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REPORTER_ASSERT(reporter, !result);
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REPORTER_ASSERT(reporter, offsetPoly.count() == 0);
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// troublesome case
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SkTDArray<SkPoint> clippedRRectPoly;
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*clippedRRectPoly.push() = SkPoint::Make(335.928101f, 428.219055f);
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*clippedRRectPoly.push() = SkPoint::Make(330.414459f, 423.034912f);
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*clippedRRectPoly.push() = SkPoint::Make(325.749084f, 417.395508f);
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*clippedRRectPoly.push() = SkPoint::Make(321.931946f, 411.300842f);
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*clippedRRectPoly.push() = SkPoint::Make(318.963074f, 404.750977f);
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*clippedRRectPoly.push() = SkPoint::Make(316.842468f, 397.745850f);
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*clippedRRectPoly.push() = SkPoint::Make(315.570068f, 390.285522f);
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*clippedRRectPoly.push() = SkPoint::Make(315.145966f, 382.369965f);
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*clippedRRectPoly.push() = SkPoint::Make(315.570068f, 374.454346f);
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*clippedRRectPoly.push() = SkPoint::Make(316.842468f, 366.994019f);
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*clippedRRectPoly.push() = SkPoint::Make(318.963074f, 359.988892f);
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*clippedRRectPoly.push() = SkPoint::Make(321.931946f, 353.439056f);
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*clippedRRectPoly.push() = SkPoint::Make(325.749084f, 347.344421f);
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*clippedRRectPoly.push() = SkPoint::Make(330.414459f, 341.705017f);
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*clippedRRectPoly.push() = SkPoint::Make(335.928101f, 336.520813f);
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*clippedRRectPoly.push() = SkPoint::Make(342.289948f, 331.791901f);
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*clippedRRectPoly.push() = SkPoint::Make(377.312134f, 331.791901f);
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*clippedRRectPoly.push() = SkPoint::Make(381.195313f, 332.532593f);
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*clippedRRectPoly.push() = SkPoint::Make(384.464935f, 334.754700f);
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*clippedRRectPoly.push() = SkPoint::Make(386.687042f, 338.024292f);
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*clippedRRectPoly.push() = SkPoint::Make(387.427765f, 341.907532f);
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*clippedRRectPoly.push() = SkPoint::Make(387.427765f, 422.832367f);
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*clippedRRectPoly.push() = SkPoint::Make(386.687042f, 426.715576f);
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*clippedRRectPoly.push() = SkPoint::Make(384.464935f, 429.985168f);
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*clippedRRectPoly.push() = SkPoint::Make(381.195313f, 432.207275f);
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*clippedRRectPoly.push() = SkPoint::Make(377.312134f, 432.947998f);
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*clippedRRectPoly.push() = SkPoint::Make(342.289948f, 432.947998f);
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REPORTER_ASSERT(reporter, is_convex(clippedRRectPoly));
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result = SkOffsetSimplePolygon(&clippedRRectPoly[0], clippedRRectPoly.count(), 32.3699417f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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REPORTER_ASSERT(reporter, is_convex(offsetPoly));
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////////////////////////////////////////////////////////////////////////////////
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// Concave tests
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SkTDArray<SkPoint> starPoly;
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*starPoly.push() = SkPoint::Make(0.0f, -50.0f);
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*starPoly.push() = SkPoint::Make(14.43f, -25.0f);
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*starPoly.push() = SkPoint::Make(43.30f, -25.0f);
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*starPoly.push() = SkPoint::Make(28.86f, 0.0f);
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*starPoly.push() = SkPoint::Make(43.30f, 25.0f);
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*starPoly.push() = SkPoint::Make(14.43f, 25.0f);
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*starPoly.push() = SkPoint::Make(0.0f, 50.0f);
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*starPoly.push() = SkPoint::Make(-14.43f, 25.0f);
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*starPoly.push() = SkPoint::Make(-43.30f, 25.0f);
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*starPoly.push() = SkPoint::Make(-28.86f, 0.0f);
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*starPoly.push() = SkPoint::Make(-43.30f, -25.0f);
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*starPoly.push() = SkPoint::Make(-14.43f, -25.0f);
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// try a variety of distances
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 0.1f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 5.665f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 28,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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// down to a point
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 28.866f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, !result);
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// and past
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 50.5f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, !result);
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// and now out
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -0.1f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -5.6665f,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -50,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -100,
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&offsetPoly);
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REPORTER_ASSERT(reporter, result);
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SkTDArray<SkPoint> intersectingPoly;
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*intersectingPoly.push() = SkPoint::Make(0.0f, -50.0f);
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*intersectingPoly.push() = SkPoint::Make(14.43f, -25.0f);
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*intersectingPoly.push() = SkPoint::Make(43.30f, -25.0f);
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*intersectingPoly.push() = SkPoint::Make(-28.86f, 0.0f);
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*intersectingPoly.push() = SkPoint::Make(43.30f, 25.0f);
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*intersectingPoly.push() = SkPoint::Make(14.43f, 25.0f);
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*intersectingPoly.push() = SkPoint::Make(0.0f, 50.0f);
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*intersectingPoly.push() = SkPoint::Make(-14.43f, 25.0f);
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*intersectingPoly.push() = SkPoint::Make(-43.30f, 25.0f);
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*intersectingPoly.push() = SkPoint::Make(28.86f, 0.0f);
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*intersectingPoly.push() = SkPoint::Make(-43.30f, -25.0f);
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*intersectingPoly.push() = SkPoint::Make(-14.43f, -25.0f);
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result = SkOffsetSimplePolygon(&intersectingPoly[0], intersectingPoly.count(), -100,
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&offsetPoly);
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REPORTER_ASSERT(reporter, !result);
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}
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