From d948ec667e0db828b98f1668ac50a1479880d4ad Mon Sep 17 00:00:00 2001
From: Frank <91616163+softhack007@users.noreply.github.com>
Date: Thu, 26 Mar 2026 12:12:32 +0100
Subject: [PATCH] fast inline color fading for bus drivers

based on upstream color_fade() and color_scale() by @DedeHai
---
 wled00/bus_manager.cpp |  2 +-
 wled00/bus_manager.h   | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/wled00/bus_manager.cpp b/wled00/bus_manager.cpp
index 9c093867..47ec11e9 100644
--- a/wled00/bus_manager.cpp
+++ b/wled00/bus_manager.cpp
@@ -1142,7 +1142,7 @@ void __attribute__((hot)) IRAM_ATTR BusHub75Matrix::setPixelColor(uint16_t pix,
 uint32_t IRAM_ATTR BusHub75Matrix::getPixelColor(uint16_t pix) const {
 // if (pix >= _len || !_ledBuffer) return BLACK; // not necessary - this was already checked at busses.getPixelColor()
 #if defined(WLEDMM_FASTPATH) && !defined(WLEDMM_SAVE_FLASH) 
-  return color_fade(uint32_t(_ledBuffer[pix]) & 0x00FFFFFF, _bri);   // this is slightly faster if we have inline color_fade()
+  return color_fade_fast(uint32_t(_ledBuffer[pix]) & 0x00FFFFFF, _bri);   // this is slightly faster if we have inline color_fade()
 #else
   return uint32_t(_ledBuffer[pix].scale8(_bri)) & 0x00FFFFFF;        // do it the FastLED way
 #endif
diff --git a/wled00/bus_manager.h b/wled00/bus_manager.h
index e61b48e3..9649ba0f 100644
--- a/wled00/bus_manager.h
+++ b/wled00/bus_manager.h
@@ -32,6 +32,28 @@ bool getBitFromArray(const uint8_t* byteArray, size_t position)  __attribute__((
 size_t getBitArrayBytes(size_t num_bits) __attribute__((const)); // number of bytes needed for an array with num_bits bits
 void setBitArray(uint8_t* byteArray, size_t numBits, bool value);  // set all bits to same value
 
+/**
+ * fast color fading / scaling - based on upstream color_fade() and color_scale() by @DedeHai
+ */
+
+// fast color fade without "video" option - fades color toward black
+static inline uint32_t color_fade_fast(uint32_t c1, uint_fast8_t amount) {
+  if (c1 == 0 || amount == 0) return 0; // black or no change
+  if (amount == 255) return c1;
+  constexpr uint32_t TWO_CHANNEL_MASK = 0x00FF00FF;
+  uint32_t rb = c1 & TWO_CHANNEL_MASK;        // extract R and B channels
+  uint32_t wg = (c1 >> 8) & TWO_CHANNEL_MASK; // extract W and G channels (shifted for multiplication)
+  uint32_t rb_scaled = ((rb * (amount + 1)) >> 8) & TWO_CHANNEL_MASK; // scale red and blue
+  uint32_t  wg_scaled = ((wg * (amount + 1)) & ~TWO_CHANNEL_MASK);    // scale white and green
+  return (rb_scaled | wg_scaled);
+}
+// faster than fastled color scaling as it does in place scaling
+static inline void CRGB_scale_fast(CRGB &c, const uint8_t scale) {
+  c.r = ((c.r * scale) >> 8);
+  c.g = ((c.g * scale) >> 8);
+  c.b = ((c.b * scale) >> 8);
+}
+
 
 #define GET_BIT(var,bit)    (((var)>>(bit))&0x01)
 #define SET_BIT(var,bit)    ((var)|=(uint16_t)(0x0001<<(bit)))