Add constant_brightness property to CWWW/RGBWW lights (#1007)

Fixes https://github.com/esphome/feature-requests/issues/460

Co-authored-by: Otto Winter <otto@otto-winter.com>

esphome/components/cwww/cwww_light_output.h

@@ -13,6 +13,7 @@ class CWWWLightOutput : public light::LightOutput {
   void set_warm_white(output::FloatOutput *warm_white) { warm_white_ = warm_white; }
   void set_cold_white_temperature(float cold_white_temperature) { cold_white_temperature_ = cold_white_temperature; }
   void set_warm_white_temperature(float warm_white_temperature) { warm_white_temperature_ = warm_white_temperature; }
+  void set_constant_brightness(bool constant_brightness) { constant_brightness_ = constant_brightness; }
   light::LightTraits get_traits() override {
     auto traits = light::LightTraits();
     traits.set_supports_brightness(true);
@@ -25,7 +26,7 @@ class CWWWLightOutput : public light::LightOutput {
   }
   void write_state(light::LightState *state) override {
     float cwhite, wwhite;
-    state->current_values_as_cwww(&cwhite, &wwhite);
+    state->current_values_as_cwww(&cwhite, &wwhite, this->constant_brightness_);
     this->cold_white_->set_level(cwhite);
     this->warm_white_->set_level(wwhite);
   }
@@ -35,6 +36,7 @@ class CWWWLightOutput : public light::LightOutput {
   output::FloatOutput *warm_white_;
   float cold_white_temperature_;
   float warm_white_temperature_;
+  bool constant_brightness_;
 };
 
 }  // namespace cwww

esphome/components/cwww/light.py

@@ -7,12 +7,15 @@ from esphome.const import CONF_OUTPUT_ID, CONF_COLD_WHITE, CONF_WARM_WHITE, \
 cwww_ns = cg.esphome_ns.namespace('cwww')
 CWWWLightOutput = cwww_ns.class_('CWWWLightOutput', light.LightOutput)
 
+CONF_CONSTANT_BRIGHTNESS = 'constant_brightness'
+
 CONFIG_SCHEMA = light.RGB_LIGHT_SCHEMA.extend({
     cv.GenerateID(CONF_OUTPUT_ID): cv.declare_id(CWWWLightOutput),
     cv.Required(CONF_COLD_WHITE): cv.use_id(output.FloatOutput),
     cv.Required(CONF_WARM_WHITE): cv.use_id(output.FloatOutput),
     cv.Required(CONF_COLD_WHITE_COLOR_TEMPERATURE): cv.color_temperature,
     cv.Required(CONF_WARM_WHITE_COLOR_TEMPERATURE): cv.color_temperature,
+    cv.Optional(CONF_CONSTANT_BRIGHTNESS, default=False): cv.boolean,
 })
 
 
@@ -26,3 +29,4 @@ def to_code(config):
     wwhite = yield cg.get_variable(config[CONF_WARM_WHITE])
     cg.add(var.set_warm_white(wwhite))
     cg.add(var.set_warm_white_temperature(config[CONF_WARM_WHITE_COLOR_TEMPERATURE]))
+    cg.add(var.set_constant_brightness(config[CONF_CONSTANT_BRIGHTNESS]))

esphome/components/light/light_color_values.h

@@ -190,24 +190,33 @@ class LightColorValues {
 
   /// Convert these light color values to an RGBWW representation with the given parameters.
   void as_rgbww(float color_temperature_cw, float color_temperature_ww, float *red, float *green, float *blue,
-                float *cold_white, float *warm_white) const {
+                float *cold_white, float *warm_white, bool constant_brightness = false) const {
     this->as_rgb(red, green, blue);
     const float color_temp = clamp(this->color_temperature_, color_temperature_cw, color_temperature_ww);
     const float ww_fraction = (color_temp - color_temperature_cw) / (color_temperature_ww - color_temperature_cw);
     const float cw_fraction = 1.0f - ww_fraction;
-    const float max_cw_ww = std::max(ww_fraction, cw_fraction);
+    *cold_white = this->state_ * this->brightness_ * this->white_ * cw_fraction;
-    *cold_white = this->state_ * this->brightness_ * this->white_ * (cw_fraction / max_cw_ww);
+    *warm_white = this->state_ * this->brightness_ * this->white_ * ww_fraction;
-    *warm_white = this->state_ * this->brightness_ * this->white_ * (ww_fraction / max_cw_ww);
+    if (!constant_brightness) {
+      const float max_cw_ww = std::max(ww_fraction, cw_fraction);
+      *cold_white /= max_cw_ww;
+      *warm_white /= max_cw_ww;
+    }
   }
 
   /// Convert these light color values to an CWWW representation with the given parameters.
-  void as_cwww(float color_temperature_cw, float color_temperature_ww, float *cold_white, float *warm_white) const {
+  void as_cwww(float color_temperature_cw, float color_temperature_ww, float *cold_white, float *warm_white,
+               bool constant_brightness = false) const {
     const float color_temp = clamp(this->color_temperature_, color_temperature_cw, color_temperature_ww);
     const float ww_fraction = (color_temp - color_temperature_cw) / (color_temperature_ww - color_temperature_cw);
     const float cw_fraction = 1.0f - ww_fraction;
-    const float max_cw_ww = std::max(ww_fraction, cw_fraction);
+    *cold_white = this->state_ * this->brightness_ * cw_fraction;
-    *cold_white = this->state_ * this->brightness_ * (cw_fraction / max_cw_ww);
+    *warm_white = this->state_ * this->brightness_ * ww_fraction;
-    *warm_white = this->state_ * this->brightness_ * (ww_fraction / max_cw_ww);
+    if (!constant_brightness) {
+      const float max_cw_ww = std::max(ww_fraction, cw_fraction);
+      *cold_white /= max_cw_ww;
+      *warm_white /= max_cw_ww;
+    }
   }
 
   /// Compare this LightColorValues to rhs, return true if and only if all attributes match.

esphome/components/light/light_state.cpp

@@ -718,19 +718,21 @@ void LightState::current_values_as_rgbw(float *red, float *green, float *blue, f
   *blue = gamma_correct(*blue, this->gamma_correct_);
   *white = gamma_correct(*white, this->gamma_correct_);
 }
-void LightState::current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white) {
+void LightState::current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white,
+                                         bool constant_brightness) {
   auto traits = this->get_traits();
   this->current_values.as_rgbww(traits.get_min_mireds(), traits.get_max_mireds(), red, green, blue, cold_white,
-                                warm_white);
+                                warm_white, constant_brightness);
   *red = gamma_correct(*red, this->gamma_correct_);
   *green = gamma_correct(*green, this->gamma_correct_);
   *blue = gamma_correct(*blue, this->gamma_correct_);
   *cold_white = gamma_correct(*cold_white, this->gamma_correct_);
   *warm_white = gamma_correct(*warm_white, this->gamma_correct_);
 }
-void LightState::current_values_as_cwww(float *cold_white, float *warm_white) {
+void LightState::current_values_as_cwww(float *cold_white, float *warm_white, bool constant_brightness) {
   auto traits = this->get_traits();
-  this->current_values.as_cwww(traits.get_min_mireds(), traits.get_max_mireds(), cold_white, warm_white);
+  this->current_values.as_cwww(traits.get_min_mireds(), traits.get_max_mireds(), cold_white, warm_white,
+                               constant_brightness);
   *cold_white = gamma_correct(*cold_white, this->gamma_correct_);
   *warm_white = gamma_correct(*warm_white, this->gamma_correct_);
 }

esphome/components/light/light_state.h

@@ -270,9 +270,10 @@ class LightState : public Nameable, public Component {
 
   void current_values_as_rgbw(float *red, float *green, float *blue, float *white);
 
-  void current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white);
+  void current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white,
+                               bool constant_brightness = false);
 
-  void current_values_as_cwww(float *cold_white, float *warm_white);
+  void current_values_as_cwww(float *cold_white, float *warm_white, bool constant_brightness = false);
 
  protected:
   friend LightOutput;

esphome/components/rgbww/light.py

@@ -8,6 +8,8 @@ from esphome.const import CONF_BLUE, CONF_GREEN, CONF_RED, CONF_OUTPUT_ID, CONF_
 rgbww_ns = cg.esphome_ns.namespace('rgbww')
 RGBWWLightOutput = rgbww_ns.class_('RGBWWLightOutput', light.LightOutput)
 
+CONF_CONSTANT_BRIGHTNESS = 'constant_brightness'
+
 CONFIG_SCHEMA = light.RGB_LIGHT_SCHEMA.extend({
     cv.GenerateID(CONF_OUTPUT_ID): cv.declare_id(RGBWWLightOutput),
     cv.Required(CONF_RED): cv.use_id(output.FloatOutput),
@@ -17,6 +19,7 @@ CONFIG_SCHEMA = light.RGB_LIGHT_SCHEMA.extend({
     cv.Required(CONF_WARM_WHITE): cv.use_id(output.FloatOutput),
     cv.Required(CONF_COLD_WHITE_COLOR_TEMPERATURE): cv.color_temperature,
     cv.Required(CONF_WARM_WHITE_COLOR_TEMPERATURE): cv.color_temperature,
+    cv.Optional(CONF_CONSTANT_BRIGHTNESS, default=False): cv.boolean,
 })
 
 
@@ -38,3 +41,4 @@ def to_code(config):
     wwhite = yield cg.get_variable(config[CONF_WARM_WHITE])
     cg.add(var.set_warm_white(wwhite))
     cg.add(var.set_warm_white_temperature(config[CONF_WARM_WHITE_COLOR_TEMPERATURE]))
+    cg.add(var.set_constant_brightness(config[CONF_CONSTANT_BRIGHTNESS]))

esphome/components/rgbww/rgbww_light_output.h

@@ -16,6 +16,7 @@ class RGBWWLightOutput : public light::LightOutput {
   void set_warm_white(output::FloatOutput *warm_white) { warm_white_ = warm_white; }
   void set_cold_white_temperature(float cold_white_temperature) { cold_white_temperature_ = cold_white_temperature; }
   void set_warm_white_temperature(float warm_white_temperature) { warm_white_temperature_ = warm_white_temperature; }
+  void set_constant_brightness(bool constant_brightness) { constant_brightness_ = constant_brightness; }
   light::LightTraits get_traits() override {
     auto traits = light::LightTraits();
     traits.set_supports_brightness(true);
@@ -28,7 +29,7 @@ class RGBWWLightOutput : public light::LightOutput {
   }
   void write_state(light::LightState *state) override {
     float red, green, blue, cwhite, wwhite;
-    state->current_values_as_rgbww(&red, &green, &blue, &cwhite, &wwhite);
+    state->current_values_as_rgbww(&red, &green, &blue, &cwhite, &wwhite, this->constant_brightness_);
     this->red_->set_level(red);
     this->green_->set_level(green);
     this->blue_->set_level(blue);
@@ -44,6 +45,7 @@ class RGBWWLightOutput : public light::LightOutput {
   output::FloatOutput *warm_white_;
   float cold_white_temperature_;
   float warm_white_temperature_;
+  bool constant_brightness_;
 };
 
 }  // namespace rgbww

tests/test1.yaml

@@ -1074,6 +1074,7 @@ light:
     warm_white: pca_6
     cold_white_color_temperature: 153 mireds
     warm_white_color_temperature: 500 mireds
+    constant_brightness: true
   - platform: fastled_clockless
     id: addr1
     chipset: WS2811