Update firmware to write to the strip only when colors changed

Author: nlamprian

arduino_code/ArduinoPixel/src/arduino_pixel_server.cpp

@@ -65,13 +65,13 @@ void ArduinoPixelServer::init(led_strip::LedStripBase *strip) {
 void ArduinoPixelServer::powerOn() {
   power_ = true;
   strip_->setMode(mode_);
-  strip_->colorize();
+  strip_->colorize(true);
 }
 
 void ArduinoPixelServer::powerOff() {
   power_ = false;
   strip_->setMode(mode_off_);
-  strip_->colorize();
+  strip_->colorize(true);
 }
 
 RequestData ArduinoPixelServer::parseRequest(Client &client) const {
@@ -264,11 +264,11 @@ void ArduinoPixelServer::updateStrip(const RequestData &request) {
       break;
     case Uri::MODE_PUT:  // Update mode
       updateMode(request.data);
-      strip_->colorize();
+      strip_->colorize(true);
       break;
     case Uri::COLOR_PUT:  // Update the LED strip color
       updateColor(request.data);
-      strip_->colorize();
+      strip_->colorize(true);
       break;
   }
 }

arduino_code/ArduinoPixel/src/arduino_pixel_server.h

@@ -29,10 +29,10 @@
 #ifndef ARDUINO_PIXEL_ARDUINO_PIXEL_SERVER_H
 #define ARDUINO_PIXEL_ARDUINO_PIXEL_SERVER_H
 
-// #define DEBUG
-
 #include <Client.h>
 
+// #define DEBUG
+
 #include "common_types.h"
 #include "server_types.h"
 #include "led_strip/led_strip_base.h"

arduino_code/ArduinoPixel/src/led_strip/led_strip_base.h

@@ -53,8 +53,9 @@ class LedStripBase {
   /**
    * \brief Updates the LED strip.
    * \details Gets the colors from the mode and updates the LED strip.
+   * \param[in] force Force updating the strip.
    */
-  virtual void colorize() = 0;
+  virtual void colorize(bool force = false) = 0;
   /**
    * \brief Gets the number of LEDs on the strip.
    * \return The number of LEDs.

arduino_code/ArduinoPixel/src/led_strip/led_strip_esp_ws2812.h

@@ -43,8 +43,8 @@ class LedStripEspWs2812 : public LedStripBase {
 
   virtual void init() override { strip_.init(); }
 
-  virtual void colorize() override {
-    mode_->update();
+  virtual void colorize(bool force = false) override {
+    if (not mode_->update() and not force) return;
     for (uint16_t idx = 0; idx < strip_.numPixels(); ++idx) {
       const Color &color = mode_->getPixel(idx);
       strip_.setPixelColor(idx, color.red, color.green, color.blue);

arduino_code/ArduinoPixel/src/led_strip/led_strip_neopixel.h

@@ -46,8 +46,8 @@ class LedStripNeoPixel : public LedStripBase {
     strip_.show();
   }
 
-  virtual void colorize() override {
-    mode_->update();
+  virtual void colorize(bool force = false) override {
+    if (not mode_->update() and not force) return;
     for (uint16_t idx = 0; idx < strip_.numPixels(); ++idx) {
       const Color &color = mode_->getPixel(idx);
       strip_.setPixelColor(idx, color.red, color.green, color.blue);

arduino_code/ArduinoPixel/src/mode/mode_base.h

@@ -47,8 +47,9 @@ class ModeBase {
    * \brief Updates the colors on the LED array.
    * \note If you think the mode as a video (sequence of images), 
    * this is where you fill the LED array with the next image.
+   * \return Flag to indicate whether the LED array has been updated.
    */
-  virtual void update() = 0;
+  virtual bool update() = 0;
   /**
    * \brief Gets the color of the request LED (aka pixel).
    * \param[in] idx the index of the pixel in the array.

arduino_code/ArduinoPixel/src/mode/rainbow_base.h

@@ -50,11 +50,12 @@ class RainbowBase : public ModeBase {
 
   virtual void init() override { setPixels(); }
 
-  virtual void update() override {
-    unsigned long new_update_time = millis();
-    if ((unsigned long)(new_update_time - last_update_time_) < period_) return;
+  virtual bool update() override {
+    unsigned long current_time = millis();
+    if ((unsigned long)(current_time - last_update_time_) < period_) return false;
     setPixels();
-    last_update_time_ = new_update_time;
+    last_update_time_ = current_time;
+    return true;
   }
 
   virtual const Color& getPixel(int idx) const override { return pixels_[idx]; }

arduino_code/ArduinoPixel/src/mode/scanner.h

@@ -59,16 +59,17 @@ class Scanner : public ModeBase {
     last_update_time_ = millis();
   }
 
-  virtual void update() override {
-    unsigned long new_update_time = millis();
-    if ((unsigned long)(new_update_time - last_update_time_) < period_) return;
+  virtual bool update() override {
+    unsigned long current_time = millis();
+    if ((unsigned long)(current_time - last_update_time_) < period_) return false;
 
     turnPixelOff(start_idx_);
     start_idx_ = (start_idx_ + 1) % num_leds_;
     end_idx_ = (end_idx_ + 1) % num_leds_;
     turnPixelOn(end_idx_);
 
-    last_update_time_ = new_update_time;
+    last_update_time_ = current_time;
+    return true;
   }
 
   virtual const Color& getPixel(int idx) const override { return pixels_[idx]; }

arduino_code/ArduinoPixel/src/mode/single_color.h

@@ -45,7 +45,7 @@ class SingleColor : public ModeBase {
 
   virtual void init() override {}
 
-  virtual void update() override {}
+  virtual bool update() override { return false; }
 
   virtual const Color& getPixel(int idx = 0) const override { return color_; }