Fix the assert and clamping in SkMatrix::get*Scale[s]().
Follow-up after https://codereview.chromium.org/2143133005/.
BUG=skia:4718
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2154123003
Review-Url: https://codereview.chromium.org/2154123003
diff --git a/src/core/SkMatrix.cpp b/src/core/SkMatrix.cpp
index fc69853..0fd8020 100644
--- a/src/core/SkMatrix.cpp
+++ b/src/core/SkMatrix.cpp
@@ -1571,19 +1571,22 @@
if (!SkScalarIsFinite(results[0])) {
return false;
}
- if (results[0] < 0 && results[0] > -SK_ScalarNearlyZero) {
+ // Due to the floating point inaccuracy, there might be an error in a, b, c
+ // calculated by sdot, further deepened by subsequent arithmetic operations
+ // on them. Therefore, we allow and cap the nearly-zero negative values.
+ SkASSERT(results[0] >= -SK_ScalarNearlyZero);
+ if (results[0] < 0) {
results[0] = 0;
}
- SkASSERT(results[0] >= 0);
results[0] = SkScalarSqrt(results[0]);
if (kBoth_MinMaxOrBoth == MIN_MAX_OR_BOTH) {
if (!SkScalarIsFinite(results[1])) {
return false;
}
- if (results[1] < 0 && results[1] > -SK_ScalarNearlyZero) {
+ SkASSERT(results[1] >= -SK_ScalarNearlyZero);
+ if (results[1] < 0) {
results[1] = 0;
}
- SkASSERT(results[1] >= 0);
results[1] = SkScalarSqrt(results[1]);
}
return true;