Guard SkMatrix::get*Scale[s]() against negative nearly-zero values.

BUG=skia:4718
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2143133005

Review-Url: https://codereview.chromium.org/2143133005
This commit is contained in:
kolczyk 2016-07-16 11:52:37 -07:00 committed by Commit bot
parent 280d537e28
commit cea22ae234
2 changed files with 16 additions and 4 deletions

View File

@ -1568,15 +1568,21 @@ template <MinMaxOrBoth MIN_MAX_OR_BOTH> bool get_scale_factor(SkMatrix::TypeMask
results[1] = apluscdiv2 + x;
}
}
if (SkScalarIsNaN(results[0])) {
if (!SkScalarIsFinite(results[0])) {
return false;
}
if (results[0] < 0 && results[0] > -SK_ScalarNearlyZero) {
results[0] = 0;
}
SkASSERT(results[0] >= 0);
results[0] = SkScalarSqrt(results[0]);
if (kBoth_MinMaxOrBoth == MIN_MAX_OR_BOTH) {
if (SkScalarIsNaN(results[1])) {
if (!SkScalarIsFinite(results[1])) {
return false;
}
if (results[1] < 0 && results[1] > -SK_ScalarNearlyZero) {
results[1] = 0;
}
SkASSERT(results[1] >= 0);
results[1] = SkScalarSqrt(results[1]);
}

View File

@ -213,11 +213,17 @@ static void test_matrix_min_max_scale(skiatest::Reporter* reporter) {
big.setAll(2.39394089e+36f, 8.85347779e+36f, 9.26526204e+36f,
3.9159619e+36f, 1.44823453e+37f, 1.51559342e+37f,
0.f, 0.f, 1.f);
REPORTER_ASSERT(reporter, -SK_Scalar1 == perspX.getMinScale());
REPORTER_ASSERT(reporter, -SK_Scalar1 == perspX.getMaxScale());
success = big.getMinMaxScales(scales);
REPORTER_ASSERT(reporter, !success);
// skbug.com/4718
SkMatrix givingNegativeNearlyZeros;
givingNegativeNearlyZeros.setAll(0.00436534f, 0.114138f, 0.37141f,
0.00358857f, 0.0936228f, -0.0174198f,
0.f, 0.f, 1.f);
success = givingNegativeNearlyZeros.getMinMaxScales(scales);
REPORTER_ASSERT(reporter, success && 0 == scales[0]);
SkMatrix perspY;
perspY.reset();
perspY.setPerspY(-SK_Scalar1 / 500);