Remove SkBitmapProcStateAutoMapper's overflow check

(follow-up to https://codereview.chromium.org/1642273002)

Add an optional SkPoint outparam, and relocate the overflow check to
the only client which needs it.

R=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1650403002

Review URL: https://codereview.chromium.org/1650403002

2 files changed, 16 insertions, 25 deletions

diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index c4b29392f1..d9d47a270f 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -586,29 +586,28 @@ static void DoNothing_shaderproc(const void*, int x, int y,
 }
 
 bool SkBitmapProcState::setupForTranslate() {
-#ifdef SK_SUPPORT_LEGACY_SAMPLER_BIAS
     SkPoint pt;
-    fInvProc(fInvMatrix, SK_ScalarHalf, SK_ScalarHalf, &pt);
 
-    const SkScalar too_big = SkIntToScalar(1 << 30);
-    if (SkScalarAbs(pt.fX) > too_big || SkScalarAbs(pt.fY) > too_big) {
-        return false;
-    }
-
-    fFilterOneX = SkScalarFloorToInt(pt.fX);
-    fFilterOneY = SkScalarFloorToInt(pt.fY);
+#ifdef SK_SUPPORT_LEGACY_SAMPLER_BIAS
+    fInvProc(fInvMatrix, SK_ScalarHalf, SK_ScalarHalf, &pt);
 #else
-    SkBitmapProcStateAutoMapper mapper(*this, 0, 0);
+    const SkBitmapProcStateAutoMapper mapper(*this, 0, 0, &pt);
+#endif
 
     /*
      *  if the translate is larger than our ints, we can get random results, or
      *  worse, we might get 0x80000000, which wreaks havoc on us, since we can't
      *  negate it.
      */
-    if (mapper.isOverflow()) {
+    const SkScalar too_big = SkIntToScalar(1 << 30);
+    if (SkScalarAbs(pt.fX) > too_big || SkScalarAbs(pt.fY) > too_big) {
         return false;
     }
 
+#ifdef SK_SUPPORT_LEGACY_SAMPLER_BIAS
+    fFilterOneX = SkScalarFloorToInt(pt.fX);
+    fFilterOneY = SkScalarFloorToInt(pt.fY);
+#else
     // Since we know we're not filtered, we re-purpose these fields allow
     // us to go from device -> src coordinates w/ just an integer add,
     // rather than running through the inverse-matrix
diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index 5e680befd2..0ae8cf2856 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -192,7 +192,8 @@ void ClampX_ClampY_nofilter_affine(const SkBitmapProcState& s,
 // TODO: filtered version which applies a fFilterOne{X,Y}/2 bias instead of epsilon?
 class SkBitmapProcStateAutoMapper {
 public:
-    SkBitmapProcStateAutoMapper(const SkBitmapProcState& s, int x, int y) {
+    SkBitmapProcStateAutoMapper(const SkBitmapProcState& s, int x, int y,
+                                SkPoint* scalarPoint = nullptr) {
         SkPoint pt;
         s.fInvProc(s.fInvMatrix,
                    SkIntToScalar(x) + SK_ScalarHalf,
@@ -207,26 +208,17 @@ public:
         fX = SkScalarToFractionalInt(pt.x()) - SkFixedToFractionalInt(biasX);
         fY = SkScalarToFractionalInt(pt.y()) - SkFixedToFractionalInt(biasY);
 
-        /*
-         *  (see SkBitmapProcState::setupForTranslate, which is the only user of this flag)
-         *
-         *  if the translate is larger than our ints, we can get random results, or
-         *  worse, we might get 0x80000000, which wreaks havoc on us, since we can't
-         *  negate it.
-         */
-        const SkScalar too_big = SkIntToScalar(1 << 30);
-        fOverflow = SkScalarAbs(pt.x() - SkFixedToScalar(biasX)) > too_big
-                 || SkScalarAbs(pt.y() - SkFixedToScalar(biasY)) > too_big;
+        if (scalarPoint) {
+            scalarPoint->set(pt.x() - SkFixedToScalar(biasX),
+                             pt.y() - SkFixedToScalar(biasY));
+        }
     }
 
     SkFractionalInt x() const { return fX; }
     SkFractionalInt y() const { return fY; }
 
-    bool isOverflow() const { return fOverflow; }
-
 private:
     SkFractionalInt fX, fY;
-    bool            fOverflow;
 };
 
 #endif