diff --git a/esphome/components/light/esp_color_correction.cpp b/esphome/components/light/esp_color_correction.cpp index 9d731a2bd56..e793226bb1e 100644 --- a/esphome/components/light/esp_color_correction.cpp +++ b/esphome/components/light/esp_color_correction.cpp @@ -22,4 +22,20 @@ uint8_t ESPColorCorrection::gamma_uncorrect_(uint8_t value) const { return (target - a <= b - target) ? lo : lo + 1; } +Color ESPColorCorrection::color_uncorrect(Color color) const { + // uncorrected = corrected^(1/gamma) / (max_brightness * local_brightness) + return Color(this->color_uncorrect_red(color.red), this->color_uncorrect_green(color.green), + this->color_uncorrect_blue(color.blue), this->color_uncorrect_white(color.white)); +} + +uint8_t ESPColorCorrection::color_uncorrect_channel_(uint8_t value, uint8_t max_brightness) const { + if (max_brightness == 0 || this->local_brightness_ == 0) + return 0; + // Use 32-bit intermediates: when max_brightness and local_brightness_ are small but non-zero, + // (uncorrected / max_brightness) * 255 can exceed 65535 before the std::min(255) clamp runs. + uint32_t uncorrected = this->gamma_uncorrect_(value) * 255UL; + uint32_t res = ((uncorrected / max_brightness) * 255UL) / this->local_brightness_; + return static_cast(std::min(res, uint32_t(255))); +} + } // namespace esphome::light diff --git a/esphome/components/light/esp_color_correction.h b/esphome/components/light/esp_color_correction.h index 48ecc463648..4eb5208c96e 100644 --- a/esphome/components/light/esp_color_correction.h +++ b/esphome/components/light/esp_color_correction.h @@ -46,38 +46,18 @@ class ESPColorCorrection { uint8_t res = esp_scale8_twice(white, this->max_brightness_.white, this->local_brightness_); return this->gamma_correct_(res); } - inline Color color_uncorrect(Color color) const ESPHOME_ALWAYS_INLINE { - // uncorrected = corrected^(1/gamma) / (max_brightness * local_brightness) - return Color(this->color_uncorrect_red(color.red), this->color_uncorrect_green(color.green), - this->color_uncorrect_blue(color.blue), this->color_uncorrect_white(color.white)); - } + Color color_uncorrect(Color color) const; inline uint8_t color_uncorrect_red(uint8_t red) const ESPHOME_ALWAYS_INLINE { - if (this->max_brightness_.red == 0 || this->local_brightness_ == 0) - return 0; - uint16_t uncorrected = this->gamma_uncorrect_(red) * 255UL; - uint16_t res = ((uncorrected / this->max_brightness_.red) * 255UL) / this->local_brightness_; - return (uint8_t) std::min(res, uint16_t(255)); + return this->color_uncorrect_channel_(red, this->max_brightness_.red); } inline uint8_t color_uncorrect_green(uint8_t green) const ESPHOME_ALWAYS_INLINE { - if (this->max_brightness_.green == 0 || this->local_brightness_ == 0) - return 0; - uint16_t uncorrected = this->gamma_uncorrect_(green) * 255UL; - uint16_t res = ((uncorrected / this->max_brightness_.green) * 255UL) / this->local_brightness_; - return (uint8_t) std::min(res, uint16_t(255)); + return this->color_uncorrect_channel_(green, this->max_brightness_.green); } inline uint8_t color_uncorrect_blue(uint8_t blue) const ESPHOME_ALWAYS_INLINE { - if (this->max_brightness_.blue == 0 || this->local_brightness_ == 0) - return 0; - uint16_t uncorrected = this->gamma_uncorrect_(blue) * 255UL; - uint16_t res = ((uncorrected / this->max_brightness_.blue) * 255UL) / this->local_brightness_; - return (uint8_t) std::min(res, uint16_t(255)); + return this->color_uncorrect_channel_(blue, this->max_brightness_.blue); } inline uint8_t color_uncorrect_white(uint8_t white) const ESPHOME_ALWAYS_INLINE { - if (this->max_brightness_.white == 0 || this->local_brightness_ == 0) - return 0; - uint16_t uncorrected = this->gamma_uncorrect_(white) * 255UL; - uint16_t res = ((uncorrected / this->max_brightness_.white) * 255UL) / this->local_brightness_; - return (uint8_t) std::min(res, uint16_t(255)); + return this->color_uncorrect_channel_(white, this->max_brightness_.white); } protected: @@ -85,6 +65,9 @@ class ESPColorCorrection { uint8_t gamma_correct_(uint8_t value) const; /// Reverse gamma: binary search the forward PROGMEM table uint8_t gamma_uncorrect_(uint8_t value) const; + /// Shared body of color_uncorrect_{red,green,blue,white}. Kept out-of-line + /// to avoid duplicating two 16-bit divides at every call site. + uint8_t color_uncorrect_channel_(uint8_t value, uint8_t max_brightness) const; const uint16_t *gamma_table_{nullptr}; Color max_brightness_{255, 255, 255, 255};