diff options
| -rw-r--r-- | core/fxcodec/codec/fx_codec_icc.cpp | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/core/fxcodec/codec/fx_codec_icc.cpp b/core/fxcodec/codec/fx_codec_icc.cpp index 29cfe0e9f4..8ffbffe985 100644 --- a/core/fxcodec/codec/fx_codec_icc.cpp +++ b/core/fxcodec/codec/fx_codec_icc.cpp @@ -1977,13 +1977,31 @@ void AdobeCMYK_to_sRGB(FX_FLOAT c, FX_FLOAT& R, FX_FLOAT& G, FX_FLOAT& B) { - uint8_t c1 = FXSYS_round(c * 255); - uint8_t m1 = FXSYS_round(m * 255); - uint8_t y1 = FXSYS_round(y * 255); - uint8_t k1 = FXSYS_round(k * 255); + // Convert to uint8_t with round-to-nearest. Avoid using FXSYS_round because + // it is incredibly expensive with VC++ (tested on VC++ 2015) because round() + // is very expensive. + // Adding 0.5f and truncating can round the wrong direction in some edge + // cases but these do not matter in this context. For instance, the float that + // is one ULP (unit in the last place) before 0.5 should round to zero but + // this will round it to one. These edge cases are never hit in this function + // due to the very limited precision of the input integers. + // This method also doesn't handle negative or extremely large numbers, but + // those are not needed here. + uint8_t c1 = int(c * 255.f + 0.5f); + uint8_t m1 = int(m * 255.f + 0.5f); + uint8_t y1 = int(y * 255.f + 0.5f); + uint8_t k1 = int(k * 255.f + 0.5f); + + ASSERT(c1 == FXSYS_round(c * 255)); + ASSERT(m1 == FXSYS_round(m * 255)); + ASSERT(y1 == FXSYS_round(y * 255)); + ASSERT(k1 == FXSYS_round(k * 255)); + uint8_t r, g, b; AdobeCMYK_to_sRGB1(c1, m1, y1, k1, r, g, b); - R = 1.0f * r / 255; - G = 1.0f * g / 255; - B = 1.0f * b / 255; + // Multiply by a constant rather than dividing because division is much + // more expensive. + R = r * (1.0f / 255); + G = g * (1.0f / 255); + B = b * (1.0f / 255); } |