tests/PathBuilderTest.cpp

/*
 * Copyright 2020 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkPath.h"
#include "include/core/SkPathBuilder.h"
#include "include/core/SkPathTypes.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRRect.h"
#include "include/core/SkRect.h"
#include "include/core/SkScalar.h"
#include "src/base/SkRandom.h"
#include "src/core/SkPathPriv.h"
#include "tests/Test.h"

#include <cstddef>
#include <cstdint>
#include <initializer_list>
#include <string>
#include <vector>

enum class SkPathConvexity;

static void is_empty(skiatest::Reporter* reporter, const SkPath& p) {
    REPORTER_ASSERT(reporter, p.getBounds().isEmpty());
    REPORTER_ASSERT(reporter, p.countPoints() == 0);
}

DEF_TEST(pathbuilder, reporter) {
    SkPathBuilder b;

    is_empty(reporter, b.snapshot());
    is_empty(reporter, b.detach());

    b.moveTo(10, 10).lineTo(20, 20).quadTo(30, 10, 10, 20);

    SkPath p0 = b.snapshot();
    SkPath p1 = b.snapshot();
    SkPath p2 = b.detach();

    // Builders should always precompute the path's bounds, so there is no race condition later
    REPORTER_ASSERT(reporter, SkPathPriv::HasComputedBounds(p0));
    REPORTER_ASSERT(reporter, SkPathPriv::HasComputedBounds(p1));
    REPORTER_ASSERT(reporter, SkPathPriv::HasComputedBounds(p2));

    REPORTER_ASSERT(reporter, p0.getBounds() == SkRect::MakeLTRB(10, 10, 30, 20));
    REPORTER_ASSERT(reporter, p0.countPoints() == 4);

    REPORTER_ASSERT(reporter, p0 == p1);
    REPORTER_ASSERT(reporter, p0 == p2);

    is_empty(reporter, b.snapshot());
    is_empty(reporter, b.detach());
}

DEF_TEST(pathbuilder_filltype, reporter) {
    for (auto fillType : { SkPathFillType::kWinding,
                           SkPathFillType::kEvenOdd,
                           SkPathFillType::kInverseWinding,
                           SkPathFillType::kInverseEvenOdd }) {
        SkPathBuilder b(fillType);

        REPORTER_ASSERT(reporter, b.fillType() == fillType);

        for (const SkPath& path : { b.snapshot(), b.detach() }) {
            REPORTER_ASSERT(reporter, path.getFillType() == fillType);
            is_empty(reporter, path);
        }
    }
}

static bool check_points(const SkPath& path, const SkPoint expected[], size_t count) {
    std::vector<SkPoint> iter_pts;

    for (auto [v, p, w] : SkPathPriv::Iterate(path)) {
        switch (v) {
            case SkPathVerb::kMove:
                iter_pts.push_back(p[0]);
                break;
            case SkPathVerb::kLine:
                iter_pts.push_back(p[1]);
                break;
            case SkPathVerb::kQuad:
            case SkPathVerb::kConic:
                iter_pts.push_back(p[1]);
                iter_pts.push_back(p[2]);
                break;
            case SkPathVerb::kCubic:
                iter_pts.push_back(p[1]);
                iter_pts.push_back(p[2]);
                iter_pts.push_back(p[3]);
                break;
            case SkPathVerb::kClose:
                break;
        }
    }
    if (iter_pts.size() != count) {
        return false;
    }
    for (size_t i = 0; i < count; ++i) {
        if (iter_pts[i] != expected[i]) {
            return false;
        }
    }
    return true;
}

DEF_TEST(pathbuilder_missing_move, reporter) {
    SkPathBuilder b;

    b.lineTo(10, 10).lineTo(20, 30);
    const SkPoint pts0[] = {
        {0, 0}, {10, 10}, {20, 30},
    };
    REPORTER_ASSERT(reporter, check_points(b.snapshot(), pts0, std::size(pts0)));

    b.reset().moveTo(20, 20).lineTo(10, 10).lineTo(20, 30).close().lineTo(60, 60);
    const SkPoint pts1[] = {
        {20, 20}, {10, 10}, {20, 30},
        {20, 20}, {60, 60},
    };
    REPORTER_ASSERT(reporter, check_points(b.snapshot(), pts1, std::size(pts1)));
}

DEF_TEST(pathbuilder_addRect, reporter) {
    const SkRect r = { 10, 20, 30, 40 };

    for (int i = 0; i < 4; ++i) {
        for (auto dir : {SkPathDirection::kCW, SkPathDirection::kCCW}) {
            SkPathBuilder b;
            b.addRect(r, dir, i);
            auto bp = b.detach();

            SkRect r2;
            bool   closed = false;
            SkPathDirection dir2;
            REPORTER_ASSERT(reporter, bp.isRect(&r2, &closed, &dir2));
            REPORTER_ASSERT(reporter, r2 == r);
            REPORTER_ASSERT(reporter, closed);
            REPORTER_ASSERT(reporter, dir == dir2);

            SkPath p;
            p.addRect(r, dir, i);
            REPORTER_ASSERT(reporter, p == bp);
        }
    }
}

static bool is_eq(const SkPath& a, const SkPath& b) {
    if (a != b) {
        return false;
    }

    {
        SkRect ra, rb;
        bool is_a = a.isOval(&ra);
        bool is_b = b.isOval(&rb);
        if (is_a != is_b) {
            return false;
        }
        if (is_a && (ra != rb)) {
            return false;
        }
    }

    {
        SkRRect rra, rrb;
        bool is_a = a.isRRect(&rra);
        bool is_b = b.isRRect(&rrb);
        if (is_a != is_b) {
            return false;
        }
        if (is_a && (rra != rrb)) {
            return false;
        }
    }

    // getConvextity() should be sufficient to test, but internally we sometimes don't want
    // to trigger computing it, so this is the stronger test for equality.
    {
        SkPathConvexity ca = SkPathPriv::GetConvexityOrUnknown(a),
                        cb = SkPathPriv::GetConvexityOrUnknown(b);
        if (ca != cb) {
            return false;
        }
    }

    return true;
}

DEF_TEST(pathbuilder_addOval, reporter) {
    const SkRect r = { 10, 20, 30, 40 };
    SkRect tmp;

    for (auto dir : {SkPathDirection::kCW, SkPathDirection::kCCW}) {
        for (int i = 0; i < 4; ++i) {
            auto bp = SkPathBuilder().addOval(r, dir, i).detach();
            SkPath p;
            p.addOval(r, dir, i);
            REPORTER_ASSERT(reporter, is_eq(p, bp));
        }
        auto bp = SkPathBuilder().addOval(r, dir).detach();
        SkPath p;
        p.addOval(r, dir);
        REPORTER_ASSERT(reporter, is_eq(p, bp));

        // test negative case -- can't have any other segments
        bp = SkPathBuilder().addOval(r, dir).lineTo(10, 10).detach();
        REPORTER_ASSERT(reporter, !bp.isOval(&tmp));
        bp = SkPathBuilder().lineTo(10, 10).addOval(r, dir).detach();
        REPORTER_ASSERT(reporter, !bp.isOval(&tmp));
    }
}

DEF_TEST(pathbuilder_addRRect, reporter) {
    const SkRRect rr = SkRRect::MakeRectXY({ 10, 20, 30, 40 }, 5, 6);

    for (auto dir : {SkPathDirection::kCW, SkPathDirection::kCCW}) {
        for (int i = 0; i < 4; ++i) {
            SkPathBuilder b;
            b.addRRect(rr, dir, i);
            auto bp = b.detach();

            SkPath p;
            p.addRRect(rr, dir, i);
            REPORTER_ASSERT(reporter, is_eq(p, bp));
        }
        auto bp = SkPathBuilder().addRRect(rr, dir).detach();
        SkPath p;
        p.addRRect(rr, dir);
        REPORTER_ASSERT(reporter, is_eq(p, bp));

        // test negative case -- can't have any other segments
        SkRRect tmp;
        bp = SkPathBuilder().addRRect(rr, dir).lineTo(10, 10).detach();
        REPORTER_ASSERT(reporter, !bp.isRRect(&tmp));
        bp = SkPathBuilder().lineTo(10, 10).addRRect(rr, dir).detach();
        REPORTER_ASSERT(reporter, !bp.isRRect(&tmp));
    }
}

DEF_TEST(pathbuilder_make, reporter) {
    constexpr int N = 100;
    uint8_t vbs[N];
    SkPoint pts[N];

    SkRandom rand;
    SkPathBuilder b;
    b.moveTo(0, 0);
    pts[0] = {0, 0}; vbs[0] = (uint8_t)SkPathVerb::kMove;
    for (int i = 1; i < N; ++i) {
        float x = rand.nextF();
        float y = rand.nextF();
        b.lineTo(x, y);
        pts[i] = {x, y}; vbs[i] = (uint8_t)SkPathVerb::kLine;
    }
    auto p0 = b.detach();
    auto p1 = SkPath::Make(pts, N, vbs, N, nullptr, 0, p0.getFillType());
    REPORTER_ASSERT(reporter, p0 == p1);
}

DEF_TEST(pathbuilder_genid, r) {
    SkPathBuilder builder;

    builder.lineTo(10, 10);
    auto p1 = builder.snapshot();

    builder.lineTo(10, 20);
    auto p2 = builder.snapshot();

    REPORTER_ASSERT(r, p1.getGenerationID() != p2.getGenerationID());
}

DEF_TEST(pathbuilder_addPolygon, reporter) {
    SkPoint pts[] = {{1, 2}, {3, 4}, {5, 6}, {7, 8}};

    auto addpoly = [](const SkPoint pts[], int count, bool isClosed) {
        SkPathBuilder builder;
        if (count > 0) {
            builder.moveTo(pts[0]);
            for (int i = 1; i < count; ++i) {
                builder.lineTo(pts[i]);
            }
            if (isClosed) {
                builder.close();
            }
        }
        return builder.detach();
    };

    for (bool isClosed : {false, true}) {
        for (size_t i = 0; i <= std::size(pts); ++i) {
            auto path0 = SkPathBuilder().addPolygon(pts, i, isClosed).detach();
            auto path1 = addpoly(pts, i, isClosed);
            REPORTER_ASSERT(reporter, path0 == path1);
        }
    }
}

DEF_TEST(pathbuilder_addPath, reporter) {
    const auto p = SkPath()
        .moveTo(10, 10)
        .lineTo(100, 10)
        .quadTo(200, 100, 100, 200)
        .close()
        .moveTo(200, 200)
        .cubicTo(210, 200, 210, 300, 200, 300)
        .conicTo(150, 250, 100, 200, 1.4f);

    REPORTER_ASSERT(reporter, p == SkPathBuilder().addPath(p).detach());
}

/*
 *  If paths were immutable, we would not have to track this, but until that day, we need
 *  to ensure that paths are built correctly/consistently with this field, regardless of
 *  either the classic mutable apis, or via SkPathBuilder (SkPath::Polygon uses builder).
 */
DEF_TEST(pathbuilder_lastmoveindex, reporter) {
    const SkPoint pts[] = {
        {0, 1}, {2, 3}, {4, 5},
    };
    constexpr int N = (int)std::size(pts);

    for (int ctrCount = 1; ctrCount < 4; ++ctrCount) {
        const int lastMoveToIndex = (ctrCount - 1) * N;

        for (bool isClosed : {false, true}) {
            SkPath a, b;

            SkPathBuilder builder;
            for (int i = 0; i < ctrCount; ++i) {
                builder.addPolygon(pts, N, isClosed);  // new-school way
                b.addPoly(pts, N, isClosed);        // old-school way
            }
            a = builder.detach();

            // We track the last moveTo verb index, and we invert it if the last verb was a close
            const int expected = isClosed ? ~lastMoveToIndex : lastMoveToIndex;
            const int a_last = SkPathPriv::LastMoveToIndex(a);
            const int b_last = SkPathPriv::LastMoveToIndex(b);

            REPORTER_ASSERT(reporter, a_last == expected);
            REPORTER_ASSERT(reporter, b_last == expected);
        }
    }
}

static void assertIsMoveTo(skiatest::Reporter* reporter, SkPathPriv::RangeIter* iter,
                           SkScalar x0, SkScalar y0) {
    auto [v, pts, w] = *(*iter)++;
    REPORTER_ASSERT(reporter, v == SkPathVerb::kMove, "%d != %d (move)",
                    (int)v, (int)SkPathVerb::kMove);
    REPORTER_ASSERT(reporter, pts[0].fX == x0, "X mismatch %f != %f", pts[0].fX, x0);
    REPORTER_ASSERT(reporter, pts[0].fY == y0, "Y mismatch %f != %f", pts[0].fY, y0);
}

static void assertIsLineTo(skiatest::Reporter* reporter, SkPathPriv::RangeIter* iter,
                           SkScalar x1, SkScalar y1) {
    auto [v, pts, w] = *(*iter)++;
    REPORTER_ASSERT(reporter, v == SkPathVerb::kLine, "%d != %d (line)",
                    (int)v, (int)SkPathVerb::kLine);
    // pts[0] is the moveTo before this line. See pts_backset_for_verb in SkPath::RangeIter
    REPORTER_ASSERT(reporter, pts[1].fX == x1, "X mismatch %f != %f", pts[1].fX, x1);
    REPORTER_ASSERT(reporter, pts[1].fY == y1, "Y mismatch %f != %f", pts[1].fY, y1);
}

static void assertIsDone(skiatest::Reporter* reporter, SkPathPriv::RangeIter* iter, SkPath* p) {
    REPORTER_ASSERT(reporter, *iter == SkPathPriv::Iterate(*p).end(), "Iterator is not done yet");
}

DEF_TEST(SkPathBuilder_lineToMoveTo, reporter) {
    SkPathBuilder pb;
    pb.moveTo(5, -1);
    pb.moveTo(20, 3);
    pb.lineTo(7, 11);
    pb.lineTo(8, 12);
    pb.moveTo(2, 3);
    pb.lineTo(20, 30);

    SkPath result = pb.detach();

    auto iter = SkPathPriv::Iterate(result).begin();
    assertIsMoveTo(reporter, &iter, 5, -1);
    assertIsMoveTo(reporter, &iter, 20, 3);
    assertIsLineTo(reporter, &iter, 7, 11);
    assertIsLineTo(reporter, &iter, 8, 12);
    assertIsMoveTo(reporter, &iter, 2, 3);
    assertIsLineTo(reporter, &iter, 20, 30);
    assertIsDone(reporter, &iter, &result);
}

DEF_TEST(SkPathBuilder_arcToPtPtRad_invalidInputsResultInALine, reporter) {
    auto test = [&](const std::string& name, SkPoint start, SkPoint end, SkScalar radius,
                    SkPoint expectedLineTo) {
        SkPathBuilder pb;
        // Remember there is an implicit moveTo(0, 0) if arcTo is the first command called.
        pb.arcTo(start, end, radius);
        SkPath result = pb.detach();

        reporter->push(name);
        auto iter = SkPathPriv::Iterate(result).begin();
        assertIsMoveTo(reporter, &iter, 0, 0);
        assertIsLineTo(reporter, &iter, expectedLineTo.fX, expectedLineTo.fY);
        assertIsDone(reporter, &iter, &result);
        reporter->pop();
    };
    // From SkPathBuilder docs:
    //   Arc is contained by tangent from last SkPath point to p1, and tangent from p1 to p2. Arc
    //   is part of circle sized to radius, positioned so it touches both tangent lines.
    // If the values cannot construct an arc, a line to the first point is constructed instead.
    test("first point equals previous point", {0, 0}, {1, 2}, 1, {0, 0});
    test("two points equal", {5, 7}, {5, 7}, 1, {5, 7});
    test("radius is zero", {-3, 5}, {-7, 11}, 0, {-3, 5});
    test("second point equals previous point", {5, 4}, {0, 0}, 1, {5, 4});
}