From 5f4834dec4acb4cfe3613a1145cc06697c5582ed Mon Sep 17 00:00:00 2001
From: Frank <91616163+softhack007@users.noreply.github.com>
Date: Mon, 5 Aug 2024 17:06:38 +0200
Subject: [PATCH] small improvements

* optimized fadeToBlackBy() - don't repaint unchanged pixels
* made MIN_HEAP_SIZE configurable by build_flags
* specific error message when not enough memory for LEDs buffer
---
 wled00/FX_fcn.cpp    | 8 +++++---
 wled00/const.h       | 3 +++
 wled00/data/index.js | 3 +++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/wled00/FX_fcn.cpp b/wled00/FX_fcn.cpp
index 65849ff1..4c43218a 100644
--- a/wled00/FX_fcn.cpp
+++ b/wled00/FX_fcn.cpp
@@ -132,7 +132,7 @@ void Segment::allocLeds() {
     ledsrgbSize = ledsrgb?size:0;
     if (ledsrgb == nullptr) {
       USER_PRINTLN("allocLeds failed!!");
-      errorFlag = ERR_LOW_MEM; // WLEDMM raise errorflag
+      errorFlag = ERR_LOW_BUF; // WLEDMM raise errorflag
     }
   }
   else {
@@ -1442,8 +1442,10 @@ void Segment::fadeToBlackBy(uint8_t fadeBy) {
 
   // WLEDMM minor optimization
   if(is2D()) {
-    for (uint_fast16_t y = 0; y < rows; y++) for (uint_fast16_t x = 0; x < cols; x++) {
-      setPixelColorXY((uint16_t)x, (uint16_t)y, CRGB(getPixelColorXY(x,y)).nscale8(scaledown));
+    for (int y = 0; y < rows; y++) for (int x = 0; x < cols; x++) {
+      uint32_t cc = getPixelColorXY(x,y);                            // WLEDMM avoid RGBW32 -> CRGB -> RGBW32 conversion
+      uint32_t cc2 = color_fade(cc, scaledown);                      // fade
+      if (cc2 != cc) setPixelColorXY((uint16_t)x, (uint16_t)y, cc2); // WLEDMM only re-paint if faded color is different
     }
   } else {
     for (uint_fast16_t x = 0; x < cols; x++) {
diff --git a/wled00/const.h b/wled00/const.h
index 5203d774..ff8b0371 100644
--- a/wled00/const.h
+++ b/wled00/const.h
@@ -352,6 +352,7 @@
 #define ERR_LOW_SEG_MEM 34  // WLEDMM: low memory (segment data RAM)
 #define ERR_LOW_WS_MEM  35  // WLEDMM: low memory (ws)
 #define ERR_LOW_AJAX_MEM  36 // WLEDMM: low memory (oappend)
+#define ERR_LOW_BUF     37  // WLEDMM: low memory (LED buffer from allocLEDs)
 
 // Timer mode types
 #define NL_MODE_SET               0            //After nightlight time elapsed, set to target brightness
@@ -480,7 +481,9 @@
 #endif
 
 //#define MIN_HEAP_SIZE (8k for AsyncWebServer)
+#if !defined(MIN_HEAP_SIZE)
 #define MIN_HEAP_SIZE 8192
+#endif
 
 // Maximum size of node map (list of other WLED instances)
 #ifdef ESP8266
diff --git a/wled00/data/index.js b/wled00/data/index.js
index e89ad78e..61480d5e 100644
--- a/wled00/data/index.js
+++ b/wled00/data/index.js
@@ -2008,6 +2008,9 @@ function readState(s,command=false)
 		case 36:
 			errstr = "Low Memory (oappend buffer).";
 		  break;
+		case 37:
+			errstr = "no memory for LEDs buffer.";
+		  break;
 		}
 	  showToast('Error ' + s.error + ": " + errstr, true);
 	}