diff options
| author |  reed@android.com <reed@android.com@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2010-03-12 19:23:27 +0000 |
|---|---|---|
| committer | reed@android.com <reed@android.com@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2010-03-12 19:23:27 +0000 |
| commit | 370eeeb03291db7e93d98d437f39fe8053b8c6fd (patch) | |
| tree | e58f3a558ae1b734b735c45f4c75afd56e900235 | |
| parent | fffe48f4aca92b3487380b2d0d6ac9e78e037a9c (diff) | |
improve precision for blend
git-svn-id: http://skia.googlecode.com/svn/trunk@529 2bbb7eff-a529-9590-31e7-b0007b416f81
| -rw-r--r-- | src/effects/SkAvoidXfermode.cpp | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/effects/SkAvoidXfermode.cpp b/src/effects/SkAvoidXfermode.cpp index d26039cec9..97bfeae0b2 100644 --- a/src/effects/SkAvoidXfermode.cpp +++ b/src/effects/SkAvoidXfermode.cpp @@ -116,6 +116,10 @@ static SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, unsigned scale) return SkPackARGB32(a, r, g, b); } +static inline unsigned Accurate255To256(unsigned x) { + return x + (x >> 7); +} + void SkAvoidXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count, const SkAlpha aa[]) { @@ -140,14 +144,14 @@ void SkAvoidXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count, // now reverse d if we need to d = MAX + (d ^ mask) - mask; SkASSERT((unsigned)d <= 255); - d = SkAlpha255To256(d); + d = Accurate255To256(d); d = scale_dist_14(d, mul, sub); SkASSERT(d <= 256); if (d > 0) { if (NULL != aa) { - d = SkAlphaMul(d, SkAlpha255To256(*aa++)); + d = SkAlphaMul(d, Accurate255To256(*aa++)); if (0 == d) { continue; } @@ -198,7 +202,7 @@ void SkAvoidXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count, if (d > 0) { if (NULL != aa) { - d = SkAlphaMul(d, SkAlpha255To256(*aa++)); + d = SkAlphaMul(d, Accurate255To256(*aa++)); if (0 == d) { continue; } @@ -239,7 +243,7 @@ void SkAvoidXfermode::xfer4444(uint16_t dst[], const SkPMColor src[], int count, if (d > 0) { if (NULL != aa) { - d = SkAlphaMul(d, SkAlpha255To256(*aa++)); + d = SkAlphaMul(d, Accurate255To256(*aa++)); if (0 == d) { continue; } |