From 4db18edb95c8aa4ce71476ae9dd9c05e3d6a3d9f Mon Sep 17 00:00:00 2001 From: Jim Van Verth Date: Tue, 3 Apr 2018 10:00:37 -0400 Subject: Add SkOffsetSimplePolygon. 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 Reviewed-by: Robert Phillips --- tests/OffsetSimplePolyTest.cpp | 210 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 tests/OffsetSimplePolyTest.cpp (limited to 'tests/OffsetSimplePolyTest.cpp') diff --git a/tests/OffsetSimplePolyTest.cpp b/tests/OffsetSimplePolyTest.cpp new file mode 100644 index 0000000000..50f680ef23 --- /dev/null +++ b/tests/OffsetSimplePolyTest.cpp @@ -0,0 +1,210 @@ +/* + * Copyright 2017 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ +#include "Test.h" +#include "SkOffsetPolygon.h" + +static bool is_convex(const SkTDArray& poly) { + if (poly.count() < 3) { + return false; + } + + SkVector v0 = poly[0] - poly[poly.count() - 1]; + SkVector v1 = poly[1] - poly[poly.count() - 1]; + SkScalar winding = v0.cross(v1); + + for (int i = 0; i < poly.count()-1; ++i) { + int j = i + 1; + int k = (i + 2) % poly.count(); + + SkVector v0 = poly[j] - poly[i]; + SkVector v1 = poly[k] - poly[i]; + SkScalar perpDot = v0.cross(v1); + if (winding*perpDot < 0) { + return false; + } + } + + return true; +} + +DEF_TEST(OffsetSimplePoly, reporter) { + SkTDArray rrectPoly; + + /////////////////////////////////////////////////////////////////////// + // Try convex tests first + + // round rect + *rrectPoly.push() = SkPoint::Make(-100, 55); + *rrectPoly.push() = SkPoint::Make(100, 55); + *rrectPoly.push() = SkPoint::Make(100 + 2.5f, 50 + 4.330127f); + *rrectPoly.push() = SkPoint::Make(100 + 3.535534f, 50 + 3.535534f); + *rrectPoly.push() = SkPoint::Make(100 + 4.330127f, 50 + 2.5f); + *rrectPoly.push() = SkPoint::Make(105, 50); + *rrectPoly.push() = SkPoint::Make(105, -50); + *rrectPoly.push() = SkPoint::Make(100 + 4.330127f, -50 - 2.5f); + *rrectPoly.push() = SkPoint::Make(100 + 3.535534f, -50 - 3.535534f); + *rrectPoly.push() = SkPoint::Make(100 + 2.5f, -50 - 4.330127f); + *rrectPoly.push() = SkPoint::Make(100, -55); + *rrectPoly.push() = SkPoint::Make(-100, -55); + *rrectPoly.push() = SkPoint::Make(-100 - 2.5f, -50 - 4.330127f); + *rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, -50 - 3.535534f); + *rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, -50 - 2.5f); + *rrectPoly.push() = SkPoint::Make(-105, -50); + *rrectPoly.push() = SkPoint::Make(-105, 50); + *rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, 50 + 2.5f); + *rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, 50 + 3.535534f); + *rrectPoly.push() = SkPoint::Make(-100 - 2.5f, 50 + 4.330127f); + REPORTER_ASSERT(reporter, is_convex(rrectPoly)); + + // inset a little + SkTDArray offsetPoly; + bool result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 3, &offsetPoly); + REPORTER_ASSERT(reporter, result); + REPORTER_ASSERT(reporter, is_convex(offsetPoly)); + + // inset to rect + result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 10, &offsetPoly); + REPORTER_ASSERT(reporter, result); + REPORTER_ASSERT(reporter, is_convex(offsetPoly)); + REPORTER_ASSERT(reporter, offsetPoly.count() == 4); + if (offsetPoly.count() == 4) { + REPORTER_ASSERT(reporter, offsetPoly[0].equals(-95, 45)); + REPORTER_ASSERT(reporter, offsetPoly[1].equals(95, 45)); + REPORTER_ASSERT(reporter, offsetPoly[2].equals(95, -45)); + REPORTER_ASSERT(reporter, offsetPoly[3].equals(-95, -45)); + } + + // just to full inset + // fails, but outputs a line segment + result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 55, &offsetPoly); + REPORTER_ASSERT(reporter, !result); + REPORTER_ASSERT(reporter, !is_convex(offsetPoly)); + REPORTER_ASSERT(reporter, offsetPoly.count() == 2); + if (offsetPoly.count() == 2) { + REPORTER_ASSERT(reporter, offsetPoly[0].equals(-50, 0)); + REPORTER_ASSERT(reporter, offsetPoly[1].equals(50, 0)); + } + + // past full inset + result = SkOffsetSimplePolygon(&rrectPoly[0], rrectPoly.count(), 75, &offsetPoly); + REPORTER_ASSERT(reporter, !result); + REPORTER_ASSERT(reporter, offsetPoly.count() == 0); + + // troublesome case + SkTDArray clippedRRectPoly; + *clippedRRectPoly.push() = SkPoint::Make(335.928101f, 428.219055f); + *clippedRRectPoly.push() = SkPoint::Make(330.414459f, 423.034912f); + *clippedRRectPoly.push() = SkPoint::Make(325.749084f, 417.395508f); + *clippedRRectPoly.push() = SkPoint::Make(321.931946f, 411.300842f); + *clippedRRectPoly.push() = SkPoint::Make(318.963074f, 404.750977f); + *clippedRRectPoly.push() = SkPoint::Make(316.842468f, 397.745850f); + *clippedRRectPoly.push() = SkPoint::Make(315.570068f, 390.285522f); + *clippedRRectPoly.push() = SkPoint::Make(315.145966f, 382.369965f); + *clippedRRectPoly.push() = SkPoint::Make(315.570068f, 374.454346f); + *clippedRRectPoly.push() = SkPoint::Make(316.842468f, 366.994019f); + *clippedRRectPoly.push() = SkPoint::Make(318.963074f, 359.988892f); + *clippedRRectPoly.push() = SkPoint::Make(321.931946f, 353.439056f); + *clippedRRectPoly.push() = SkPoint::Make(325.749084f, 347.344421f); + *clippedRRectPoly.push() = SkPoint::Make(330.414459f, 341.705017f); + *clippedRRectPoly.push() = SkPoint::Make(335.928101f, 336.520813f); + *clippedRRectPoly.push() = SkPoint::Make(342.289948f, 331.791901f); + *clippedRRectPoly.push() = SkPoint::Make(377.312134f, 331.791901f); + *clippedRRectPoly.push() = SkPoint::Make(381.195313f, 332.532593f); + *clippedRRectPoly.push() = SkPoint::Make(384.464935f, 334.754700f); + *clippedRRectPoly.push() = SkPoint::Make(386.687042f, 338.024292f); + *clippedRRectPoly.push() = SkPoint::Make(387.427765f, 341.907532f); + *clippedRRectPoly.push() = SkPoint::Make(387.427765f, 422.832367f); + *clippedRRectPoly.push() = SkPoint::Make(386.687042f, 426.715576f); + *clippedRRectPoly.push() = SkPoint::Make(384.464935f, 429.985168f); + *clippedRRectPoly.push() = SkPoint::Make(381.195313f, 432.207275f); + *clippedRRectPoly.push() = SkPoint::Make(377.312134f, 432.947998f); + *clippedRRectPoly.push() = SkPoint::Make(342.289948f, 432.947998f); + REPORTER_ASSERT(reporter, is_convex(clippedRRectPoly)); + + result = SkOffsetSimplePolygon(&clippedRRectPoly[0], clippedRRectPoly.count(), 32.3699417f, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + REPORTER_ASSERT(reporter, is_convex(offsetPoly)); + + //////////////////////////////////////////////////////////////////////////////// + // Concave tests + + SkTDArray starPoly; + *starPoly.push() = SkPoint::Make(0.0f, -50.0f); + *starPoly.push() = SkPoint::Make(14.43f, -25.0f); + *starPoly.push() = SkPoint::Make(43.30f, -25.0f); + *starPoly.push() = SkPoint::Make(28.86f, 0.0f); + *starPoly.push() = SkPoint::Make(43.30f, 25.0f); + *starPoly.push() = SkPoint::Make(14.43f, 25.0f); + *starPoly.push() = SkPoint::Make(0.0f, 50.0f); + *starPoly.push() = SkPoint::Make(-14.43f, 25.0f); + *starPoly.push() = SkPoint::Make(-43.30f, 25.0f); + *starPoly.push() = SkPoint::Make(-28.86f, 0.0f); + *starPoly.push() = SkPoint::Make(-43.30f, -25.0f); + *starPoly.push() = SkPoint::Make(-14.43f, -25.0f); + + // try a variety of distances + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 0.1f, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 5.665f, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 28, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + // down to a point + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 28.866f, + &offsetPoly); + REPORTER_ASSERT(reporter, !result); + + // and past + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), 50.5f, + &offsetPoly); + REPORTER_ASSERT(reporter, !result); + + // and now out + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -0.1f, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -5.6665f, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -50, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + result = SkOffsetSimplePolygon(&starPoly[0], starPoly.count(), -100, + &offsetPoly); + REPORTER_ASSERT(reporter, result); + + SkTDArray intersectingPoly; + *intersectingPoly.push() = SkPoint::Make(0.0f, -50.0f); + *intersectingPoly.push() = SkPoint::Make(14.43f, -25.0f); + *intersectingPoly.push() = SkPoint::Make(43.30f, -25.0f); + *intersectingPoly.push() = SkPoint::Make(-28.86f, 0.0f); + *intersectingPoly.push() = SkPoint::Make(43.30f, 25.0f); + *intersectingPoly.push() = SkPoint::Make(14.43f, 25.0f); + *intersectingPoly.push() = SkPoint::Make(0.0f, 50.0f); + *intersectingPoly.push() = SkPoint::Make(-14.43f, 25.0f); + *intersectingPoly.push() = SkPoint::Make(-43.30f, 25.0f); + *intersectingPoly.push() = SkPoint::Make(28.86f, 0.0f); + *intersectingPoly.push() = SkPoint::Make(-43.30f, -25.0f); + *intersectingPoly.push() = SkPoint::Make(-14.43f, -25.0f); + + result = SkOffsetSimplePolygon(&intersectingPoly[0], intersectingPoly.count(), -100, + &offsetPoly); + REPORTER_ASSERT(reporter, !result); + + + +} -- cgit v1.2.3