From 771f110b145c5c6589c3558b0a5d1d5f6603a538 Mon Sep 17 00:00:00 2001
From: Frank <91616163+softhack007@users.noreply.github.com>
Date: Fri, 10 Jan 2025 18:48:47 +0100
Subject: [PATCH] experimental: prevent strip flickering when loading presets
 from UI

* wait until strip.service() is done
* blank strip
* wait until all LEDs are updated
* load new preset
---
 wled00/presets.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/wled00/presets.cpp b/wled00/presets.cpp
index 60a7e1c6..3e5b4142 100644
--- a/wled00/presets.cpp
+++ b/wled00/presets.cpp
@@ -233,8 +233,16 @@ void handlePresets()
   DEBUG_PRINT(F("Applying preset: "));
   DEBUG_PRINTLN(tmpPreset);
 
+  bool haveLocked = false;
   #if defined(ARDUINO_ARCH_ESP32)   // WLEDMM we apply this workaround to all esp32 boards (S3 and classic esp32 included)
   //#if defined(ARDUINO_ARCH_ESP32S2) || defined(ARDUINO_ARCH_ESP32C3)
+  // in case we are called from web UI, wait until strip.service() is done
+  if (!suspendStripService) { suspendStripService = true; haveLocked = true; } // only lock service if not locked already
+  unsigned long waitstart = millis();
+  while (strip.isServicing() && millis() - waitstart < FRAMETIME_FIXED) delay(1); // wait for effects to finish updating
+
+  strip.fill(BLACK); strip.show(); // experimental: set LEDs to black while new preset loads (instead of freezing effects)
+
   unsigned long start = millis();
   while (strip.isUpdating() && millis() - start < FRAMETIME_FIXED) delay(1); // wait for strip to finish updating, accessing FS during sendout causes glitches // WLEDMM delay instead of yield
   #endif
@@ -250,6 +258,7 @@ void handlePresets()
     if ((errorFlag == ERR_FS_PLOAD) || (errorFlag == ERR_JSON)) errorFlag = ERR_NONE;  // WLEDMM only reset our own error
     if (presetErrorFlag == ERR_FS_PLOAD) errorFlag = presetErrorFlag;
   }
+  if (haveLocked) suspendStripService = false; // WLEDMM unlock effects after presets file was loaded
   fdo = fileDoc->as<JsonObject>();
 
   //HTTP API commands