Repeating SkBitmapProcState rounding bias

src/core/SkBitmapProcState.h

Index: src/core/SkBitmapProcState.h
diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index e6e7a3f393661ff729a2abecde11d62950b5e6a6..51750baef77ab55ab5d7d2c2edb5236076f069f3 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -25,17 +25,6 @@ typedef SkFixed3232    SkFractionalInt;
 #define SkFixedToFractionalInt(x)   SkFixedToFixed3232(x)
 #define SkFractionalIntToInt(x)     SkFixed3232ToInt(x)
 
-// Applying a fixed point (SkFixed, SkFractionalInt) epsilon bias ensures that the inverse-mapped
-// bitmap coordinates are rounded consistently WRT geometry.  Note that we only have to do this
-// when the scale is positive - for negative scales we're already rounding in the right direction.
-static inline int bitmap_sampler_inv_bias(SkScalar scale) {
-#ifndef SK_SUPPORT_LEGACY_BITMAP_SAMPLER_BIAS
-    return -(scale > 0);
-#else
-    return 0;
-#endif
-}
-
 class SkPaint;
 
 struct SkBitmapProcState {
@@ -87,6 +76,12 @@ struct SkBitmapProcState {
     SkPMColor           fPaintPMColor;      // chooseProcs - A8 config
     SkFixed             fInvSx;             // chooseProcs
     SkFixed             fInvKy;             // chooseProcs
+
+    // Epsilon bias to ensure inverse-mapped bitmap coordinates are rounded consistently WRT
+    // geometry.  These are treated as SkFixed, but we only store the fractional part.

[reed1, 2015/12/16 16:25:03]

We just need 0 or 1 for each, right? why using int16_t?

[f(malita), 2015/12/16 16:45:55]

The current impl also expects an explicit sign.  We could

a) make the sign implicit and squeeze these down to 1 bit each
b) squeeze them down to int8_ts - I think these should fit in the struct padding
if placed at the end

Do you think b) will work?

+    int16_t             fInvBiasX;          // chooseProcs
+    int16_t             fInvBiasY;          // chooseProcs
+
     uint16_t            fAlphaScale;        // chooseProcs
     uint8_t             fInvType;           // chooseProcs
     uint8_t             fTileModeX;         // CONSTRUCTOR