From 019a40791eb6ee5ed1487b3b5bc80884fcb86164 Mon Sep 17 00:00:00 2001
From: Mikey Sklar <mikeysklar@gmail.com>
Date: Fri, 16 Oct 2026 18:56:21 -0700
Subject: [PATCH] Give Adafruit_GFX a virtual destructor except on AVR

Deleting a canvas or display through an Adafruit_GFX pointer called
only the base destructor, so the canvas buffer leaked (#369). AVR is
left out because a virtual destructor links malloc and free into
display sketches that never use the heap (+602 bytes on an Uno).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
---
 Adafruit_GFX.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Adafruit_GFX.h b/Adafruit_GFX.h
index 7806f01..a75e5fb 100644
--- a/Adafruit_GFX.h
+++ b/Adafruit_GFX.h
@@ -19,6 +19,11 @@ class Adafruit_GFX : public Print {
 
 public:
   Adafruit_GFX(int16_t w, int16_t h); // Constructor
+#if !defined(__AVR__)
+  // Virtual so deleting a canvas or display through an Adafruit_GFX pointer
+  // frees it. Skipped on AVR, where it links malloc/free into every sketch.
+  virtual ~Adafruit_GFX() {}
+#endif
 
   /**********************************************************************/
   /*!