diff options
| author |  Mike Klein <mtklein@chromium.org> | 2017-01-17 10:19:50 -0500 |
|---|---|---|
| committer |  Skia Commit-Bot <skia-commit-bot@chromium.org> | 2017-01-17 16:05:11 +0000 |
| commit | d32b8177da4efad14a609c7c34784dffb47575ee (patch) | |
| tree | 8edd4c3bdd32b363c8a03b7e856048cf3224665f | |
| parent | eaf0079d81beac9fea2da7a20c3587ebbbbe6463 (diff) | |
add and test SkFixed15::to_u8()
Change-Id: Iedbcd2d938122cdc8f6b235745eb6165e348c237
Reviewed-on: https://skia-review.googlesource.com/7108
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>
| -rw-r--r-- | src/core/SkFixed15.h | 6 | ||||
| -rw-r--r-- | tests/SkFixed15Test.cpp | 5 |
2 files changed, 11 insertions, 0 deletions
diff --git a/src/core/SkFixed15.h b/src/core/SkFixed15.h index 43a9fae773..509febc7c1 100644 --- a/src/core/SkFixed15.h +++ b/src/core/SkFixed15.h @@ -32,6 +32,12 @@ public: + ((val+1)>>8); // All val but 255 are correct. +1 if val == 255 to get 32768. } + uint8_t to_u8() const { + // FromU8() and to_u8() roundtrip all bytes. + // There is still much room to tweak this towards the ideal, a rounding scale by 255/32768. + return (fVal - (fVal>>8))>>7; + } + SkFixed15 operator +(SkFixed15 o) const { return fVal + o.fVal; } SkFixed15 operator -(SkFixed15 o) const { return fVal - o.fVal; } SkFixed15 operator *(SkFixed15 o) const { return (fVal * o.fVal + (1<<14)) >> 15; } diff --git a/tests/SkFixed15Test.cpp b/tests/SkFixed15Test.cpp index e2108d5604..df957b1e49 100644 --- a/tests/SkFixed15Test.cpp +++ b/tests/SkFixed15Test.cpp @@ -26,4 +26,9 @@ DEF_TEST(SkFixed15, r) { for (int x = 0; x < 256; x++) { REPORTER_ASSERT(r, SkFixed15::FromU8(x) == SkFixed15(x * (1/255.0f))); } + + // to_u8() and FromU8() should roundtrip all bytes. + for (int x = 0; x < 256; x++) { + REPORTER_ASSERT(r, x == SkFixed15::FromU8(x).to_u8()); + } } |