From b68d36bb851840686a88d46bd9f6ff8435493325 Mon Sep 17 00:00:00 2001
From: David Gwilliam <dhgwilliam@gmail.com>
Date: Fri, 20 Feb 2026 02:41:04 -0800
Subject: [PATCH] perf(DisplayDriverTFT): Throttle alert redraws to prevent
 tearing

---
 boards/esp32-32e-4/DisplayDriverTFT.cpp | 10 +++++++++-
 boards/esp32-32e-4/DisplayDriverTFT.h   |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/boards/esp32-32e-4/DisplayDriverTFT.cpp b/boards/esp32-32e-4/DisplayDriverTFT.cpp
index cc6f521..726615a 100644
--- a/boards/esp32-32e-4/DisplayDriverTFT.cpp
+++ b/boards/esp32-32e-4/DisplayDriverTFT.cpp
@@ -193,8 +193,16 @@ void DisplayDriverTFT::drawBoot(const ScreenState& st) {
 }
 
 void DisplayDriverTFT::drawAlert(const ScreenState& st) {
+    // Throttle redraws to ~24fps to prevent tearing
+    uint32_t now = millis();
+    if(now - _lastAlertDrawMs < ALERT_DRAW_INTERVAL_MS) {
+        return;
+    }
+    _lastAlertDrawMs = now;
+
     uint32_t elapsed = millis() - st.alertStartMs;
-    uint8_t pulse = 180 + (uint8_t)(75.0f * sinf(elapsed / 300.0f));
+    // Slower pulse - divide by 1500 for ~9.4 second cycle (was 300 for ~1.9s)
+    uint8_t pulse = 180 + (uint8_t)(75.0f * sinf(elapsed / 1500.0f));
     uint16_t bg = _tft.color565(pulse, 0, 0);
 
     _tft.fillScreen(bg);
diff --git a/boards/esp32-32e-4/DisplayDriverTFT.h b/boards/esp32-32e-4/DisplayDriverTFT.h
index e4f9e2f..c225406 100644
--- a/boards/esp32-32e-4/DisplayDriverTFT.h
+++ b/boards/esp32-32e-4/DisplayDriverTFT.h
@@ -44,7 +44,9 @@ private:
     // Touch hint for alert - progressive fill from bottom
     bool _alertTouchDown = false;
     uint32_t _alertTouchStartMs = 0;
+    uint32_t _lastAlertDrawMs = 0;
     static constexpr uint32_t ALERT_FILL_DURATION_MS = 3000;
+    static constexpr uint32_t ALERT_DRAW_INTERVAL_MS = 333; // ~3fps
 
     // Touch tracking for press/release detection
     bool _touchWasPressed = false;