static void TestMatrix(skiatest::Reporter* reporter) {
    SkMatrix    mat, inverse, iden1, iden2;

    mat.reset();
    mat.setTranslate(SK_Scalar1, SK_Scalar1);
    REPORTER_ASSERT(reporter, mat.invert(&inverse));
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));

    mat.setScale(SkIntToScalar(2), SkIntToScalar(4));
    REPORTER_ASSERT(reporter, mat.invert(&inverse));
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    test_flatten(reporter, mat);

    mat.setScale(SK_Scalar1/2, SkIntToScalar(2));
    REPORTER_ASSERT(reporter, mat.invert(&inverse));
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    test_flatten(reporter, mat);

    mat.setScale(SkIntToScalar(3), SkIntToScalar(5), SkIntToScalar(20), 0);
    mat.postRotate(SkIntToScalar(25));
    REPORTER_ASSERT(reporter, mat.invert(NULL));
    REPORTER_ASSERT(reporter, mat.invert(&inverse));
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    iden2.setConcat(inverse, mat);
    REPORTER_ASSERT(reporter, is_identity(iden2));
    test_flatten(reporter, mat);
    test_flatten(reporter, iden2);

    mat.setScale(0, SK_Scalar1);
    REPORTER_ASSERT(reporter, !mat.invert(NULL));
    REPORTER_ASSERT(reporter, !mat.invert(&inverse));
    mat.setScale(SK_Scalar1, 0);
    REPORTER_ASSERT(reporter, !mat.invert(NULL));
    REPORTER_ASSERT(reporter, !mat.invert(&inverse));

    // rectStaysRect test
    {
        static const struct {
            SkScalar    m00, m01, m10, m11;
            bool        mStaysRect;
        }
        gRectStaysRectSamples[] = {
            {          0,          0,          0,           0, false },
            {          0,          0,          0,  SK_Scalar1, false },
            {          0,          0, SK_Scalar1,           0, false },
            {          0,          0, SK_Scalar1,  SK_Scalar1, false },
            {          0, SK_Scalar1,          0,           0, false },
            {          0, SK_Scalar1,          0,  SK_Scalar1, false },
            {          0, SK_Scalar1, SK_Scalar1,           0, true },
            {          0, SK_Scalar1, SK_Scalar1,  SK_Scalar1, false },
            { SK_Scalar1,          0,          0,           0, false },
            { SK_Scalar1,          0,          0,  SK_Scalar1, true },
            { SK_Scalar1,          0, SK_Scalar1,           0, false },
            { SK_Scalar1,          0, SK_Scalar1,  SK_Scalar1, false },
            { SK_Scalar1, SK_Scalar1,          0,           0, false },
            { SK_Scalar1, SK_Scalar1,          0,  SK_Scalar1, false },
            { SK_Scalar1, SK_Scalar1, SK_Scalar1,           0, false },
            { SK_Scalar1, SK_Scalar1, SK_Scalar1,  SK_Scalar1, false }
        };

        for (size_t i = 0; i < SK_ARRAY_COUNT(gRectStaysRectSamples); i++) {
            SkMatrix    m;

            m.reset();
            m.set(SkMatrix::kMScaleX, gRectStaysRectSamples[i].m00);
            m.set(SkMatrix::kMSkewX,  gRectStaysRectSamples[i].m01);
            m.set(SkMatrix::kMSkewY,  gRectStaysRectSamples[i].m10);
            m.set(SkMatrix::kMScaleY, gRectStaysRectSamples[i].m11);
            REPORTER_ASSERT(reporter,
                    m.rectStaysRect() == gRectStaysRectSamples[i].mStaysRect);
        }
    }

    mat.reset();
    mat.set(SkMatrix::kMScaleX, SkIntToScalar(1));
    mat.set(SkMatrix::kMSkewX,  SkIntToScalar(2));
    mat.set(SkMatrix::kMTransX, SkIntToScalar(3));
    mat.set(SkMatrix::kMSkewY,  SkIntToScalar(4));
    mat.set(SkMatrix::kMScaleY, SkIntToScalar(5));
    mat.set(SkMatrix::kMTransY, SkIntToScalar(6));
    SkScalar affine[6];
    REPORTER_ASSERT(reporter, mat.asAffine(affine));

    #define affineEqual(e) affine[SkMatrix::kA##e] == mat.get(SkMatrix::kM##e)
    REPORTER_ASSERT(reporter, affineEqual(ScaleX));
    REPORTER_ASSERT(reporter, affineEqual(SkewY));
    REPORTER_ASSERT(reporter, affineEqual(SkewX));
    REPORTER_ASSERT(reporter, affineEqual(ScaleY));
    REPORTER_ASSERT(reporter, affineEqual(TransX));
    REPORTER_ASSERT(reporter, affineEqual(TransY));
    #undef affineEqual

    mat.set(SkMatrix::kMPersp1, SkScalarToPersp(SK_Scalar1 / 2));
    REPORTER_ASSERT(reporter, !mat.asAffine(affine));

    SkMatrix mat2;
    mat2.reset();
    mat.reset();
    SkScalar zero = 0;
    mat.set(SkMatrix::kMSkewX, -zero);
    REPORTER_ASSERT(reporter, are_equal(reporter, mat, mat2));

    mat2.reset();
    mat.reset();
    mat.set(SkMatrix::kMSkewX, SK_ScalarNaN);
    mat2.set(SkMatrix::kMSkewX, SK_ScalarNaN);
    // fixed pt doesn't have the property that NaN does not equal itself.
#ifdef SK_SCALAR_IS_FIXED
    REPORTER_ASSERT(reporter, are_equal(reporter, mat, mat2));
#else
    REPORTER_ASSERT(reporter, !are_equal(reporter, mat, mat2));
#endif

    test_matrix_max_stretch(reporter);
    test_matrix_is_similarity(reporter);
    test_matrix_recttorect(reporter);
    test_matrix_decomposition(reporter);
}
void TestMatrix(skiatest::Reporter* reporter) {
    SkMatrix    mat, inverse, iden1, iden2;

    mat.reset();
    mat.setTranslate(SK_Scalar1, SK_Scalar1);
    mat.invert(&inverse);
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));

    mat.setScale(SkIntToScalar(2), SkIntToScalar(2));
    mat.invert(&inverse);
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    test_flatten(reporter, mat);

    mat.setScale(SK_Scalar1/2, SK_Scalar1/2);
    mat.invert(&inverse);
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    test_flatten(reporter, mat);

    mat.setScale(SkIntToScalar(3), SkIntToScalar(5), SkIntToScalar(20), 0);
    mat.postRotate(SkIntToScalar(25));
    REPORTER_ASSERT(reporter, mat.invert(NULL));
    mat.invert(&inverse);
    iden1.setConcat(mat, inverse);
    REPORTER_ASSERT(reporter, is_identity(iden1));
    iden2.setConcat(inverse, mat);
    REPORTER_ASSERT(reporter, is_identity(iden2));
    test_flatten(reporter, mat);
    test_flatten(reporter, iden2);

    // rectStaysRect test
    {
        static const struct {
            SkScalar    m00, m01, m10, m11;
            bool        mStaysRect;
        }
        gRectStaysRectSamples[] = {
            {          0,          0,          0,           0, false },
            {          0,          0,          0,  SK_Scalar1, false },
            {          0,          0, SK_Scalar1,           0, false },
            {          0,          0, SK_Scalar1,  SK_Scalar1, false },
            {          0, SK_Scalar1,          0,           0, false },
            {          0, SK_Scalar1,          0,  SK_Scalar1, false },
            {          0, SK_Scalar1, SK_Scalar1,           0, true },
            {          0, SK_Scalar1, SK_Scalar1,  SK_Scalar1, false },
            { SK_Scalar1,          0,          0,           0, false },
            { SK_Scalar1,          0,          0,  SK_Scalar1, true },
            { SK_Scalar1,          0, SK_Scalar1,           0, false },
            { SK_Scalar1,          0, SK_Scalar1,  SK_Scalar1, false },
            { SK_Scalar1, SK_Scalar1,          0,           0, false },
            { SK_Scalar1, SK_Scalar1,          0,  SK_Scalar1, false },
            { SK_Scalar1, SK_Scalar1, SK_Scalar1,           0, false },
            { SK_Scalar1, SK_Scalar1, SK_Scalar1,  SK_Scalar1, false }
        };

        for (size_t i = 0; i < SK_ARRAY_COUNT(gRectStaysRectSamples); i++) {
            SkMatrix    m;

            m.reset();
            m.set(SkMatrix::kMScaleX, gRectStaysRectSamples[i].m00);
            m.set(SkMatrix::kMSkewX,  gRectStaysRectSamples[i].m01);
            m.set(SkMatrix::kMSkewY,  gRectStaysRectSamples[i].m10);
            m.set(SkMatrix::kMScaleY, gRectStaysRectSamples[i].m11);
            REPORTER_ASSERT(reporter,
                    m.rectStaysRect() == gRectStaysRectSamples[i].mStaysRect);
        }
    }

    mat.reset();
    mat.set(SkMatrix::kMScaleX, SkIntToScalar(1));
    mat.set(SkMatrix::kMSkewX,  SkIntToScalar(2));
    mat.set(SkMatrix::kMTransX, SkIntToScalar(3));
    mat.set(SkMatrix::kMSkewY,  SkIntToScalar(4));
    mat.set(SkMatrix::kMScaleY, SkIntToScalar(5));
    mat.set(SkMatrix::kMTransY, SkIntToScalar(6));
    SkScalar affine[6];
    REPORTER_ASSERT(reporter, mat.asAffine(affine));

    #define affineEqual(e) affine[SkMatrix::kA##e] == mat.get(SkMatrix::kM##e)
    REPORTER_ASSERT(reporter, affineEqual(ScaleX));
    REPORTER_ASSERT(reporter, affineEqual(SkewY));
    REPORTER_ASSERT(reporter, affineEqual(SkewX));
    REPORTER_ASSERT(reporter, affineEqual(ScaleY));
    REPORTER_ASSERT(reporter, affineEqual(TransX));
    REPORTER_ASSERT(reporter, affineEqual(TransY));
    #undef affineEqual

    mat.set(SkMatrix::kMPersp1, SkScalarToPersp(SK_Scalar1 / 2));
    REPORTER_ASSERT(reporter, !mat.asAffine(affine));

    test_matrix_max_stretch(reporter);
}