Set analytic AA as default.

We'll use https://codereview.chromium.org/2471123002/ to keep Chrome from using
analytic AA until we fix all the Chrome tests.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2471133002

Committed: https://skia.googlesource.com/skia/+/dca4f6530013cf43a2557ccb07f5cb4fd916b8e8
Review-Url: https://codereview.chromium.org/2471133002

4 files changed, 7 insertions, 5 deletions

diff --git a/src/core/SkAntiRun.h b/src/core/SkAntiRun.h
index 5ac0e62a6c..8b19036d6c 100644
--- a/src/core/SkAntiRun.h
+++ b/src/core/SkAntiRun.h
@@ -23,6 +23,7 @@ public:
 
     // Return 0-255 given 0-256
     static inline SkAlpha CatchOverflow(int alpha) {
+        SkASSERT(alpha >= 0 && alpha <= 256);
         return alpha - (alpha >> 8);
     }
 
diff --git a/src/core/SkScan.cpp b/src/core/SkScan.cpp
index a7ecf31826..5a02c61b44 100644
--- a/src/core/SkScan.cpp
+++ b/src/core/SkScan.cpp
@@ -10,10 +10,10 @@
 #include "SkBlitter.h"
 #include "SkRasterClip.h"
 
-#ifdef SK_ANALYTIC_AA
-    std::atomic<bool> gSkUseAnalyticAA{true};
-#else
+#ifdef SK_NO_ANALYTIC_AA
     std::atomic<bool> gSkUseAnalyticAA{false};
+#else
+    std::atomic<bool> gSkUseAnalyticAA{true};
 #endif
 
 static inline void blitrect(SkBlitter* blitter, const SkIRect& r) {
diff --git a/src/core/SkScan_AAAPath.cpp b/src/core/SkScan_AAAPath.cpp
index aab253ce8d..8ca2fea714 100644
--- a/src/core/SkScan_AAAPath.cpp
+++ b/src/core/SkScan_AAAPath.cpp
@@ -485,7 +485,7 @@ static inline SkAlpha partialTriangleToAlpha(SkFixed a, SkFixed b) {
 }
 
 static inline SkAlpha getPartialAlpha(SkAlpha alpha, SkFixed partialHeight) {
-    return (alpha * partialHeight + SK_FixedHalf) >> 16;
+    return SkToU8(SkFixedRoundToInt(alpha * partialHeight));
 }
 
 static inline SkAlpha getPartialAlpha(SkAlpha alpha, SkAlpha fullAlpha) {
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index 6894b84238..64ce04d851 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -949,7 +949,8 @@ template <Sk4f (blend)(const Sk4f&, const Sk4f&)> SkPM4f proc_4f(const SkPM4f& s
     assert_unit(s);
     assert_unit(d);
     SkPM4f r = as_pm4f(blend(as_4f(s), as_4f(d)));
-    assert_unit(r);
+    // Turn this assert off for now because srgb conversions may end up in rgb > a
+    // assert_unit(r);
     return r;
 }