diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/private/SkFixed.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/private/SkFixed.h b/include/private/SkFixed.h index adb0343bc7..05e1de49c9 100644 --- a/include/private/SkFixed.h +++ b/include/private/SkFixed.h @@ -30,6 +30,11 @@ typedef int32_t SkFixed; #define SK_FixedTanPIOver8 (0x6A0A) #define SK_FixedRoot2Over2 (0xB505) +// NOTE: SkFixedToFloat is exact. SkFloatToFixed seems to lack a rounding step. For all fixed-point +// values, this version is as accurate as possible for (fixed -> float -> fixed). Rounding reduces +// accuracy if the intermediate floats are in the range that only holds integers (adding 0.5f to an +// odd integer then snaps to nearest even). Using double for the rounding math gives maximum +// accuracy for (float -> fixed -> float), but that's usually overkill. #define SkFixedToFloat(x) ((x) * 1.52587890625e-5f) #define SkFloatToFixed(x) sk_float_saturate2int((x) * SK_Fixed1) |