LVGL 9 tuning: CPU 86% -> 53% at full GIF speed (display_gif_embedded)

- render in RGB565_SWAPPED (ST77916 byte order), no swap pass in flush;
  flush swaps only if the display format is plain RGB565 (runtime check,
  the previous #if compared enum values and was always true)
- QSPI clock 50 -> 80 MHz
- LV_ATTRIBUTE_FAST_MEM / FLUSH_READY in IRAM (lv_attr_jc3636w518.h)
- display_gif_embedded: GIF decoded in the display's color format (no alpha)
- tested without gain: LV_GIF_CACHE_DECODE_DATA (unused in 9.6), 120-row buffers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shared/include/lv_attr_jc3636w518.h

@@ -0,0 +1,15 @@
+/* LVGL attribute overrides for the JC3636W518 (ESP32-S3), included via LV_ATTRIBUTE_CUSTOM_INCLUDE in lv_conf.h */
+#ifndef LV_ATTR_JC3636W518_H
+#define LV_ATTR_JC3636W518_H
+
+#if !defined(__ASSEMBLY__)
+#include <esp_attr.h>
+#endif
+
+/* hot drawing/blending functions in internal RAM instead of flash (via cache) */
+#define LV_ATTRIBUTE_FAST_MEM IRAM_ATTR
+
+/* lv_display_flush_ready() is called from the LCD DMA-done interrupt: keep it in IRAM */
+#define LV_ATTRIBUTE_FLUSH_READY IRAM_ATTR
+
+#endif

shared/include/lv_conf.h

@@ -142,7 +142,7 @@
  *  - LV_COLOR_FORMAT_ARGB8888
  *  - LV_COLOR_FORMAT_ARGB8888_PREMULTIPLIED
  */
-#define LV_COLOR_FORMAT_DEFAULT LV_COLOR_FORMAT_RGB565
+#define LV_COLOR_FORMAT_DEFAULT LV_COLOR_FORMAT_RGB565_SWAPPED  /* JC3636W518: ST77916 byte order, no swap in flush */
 
 /** 0: no adjustment, get the integer part of the result (round down)
  *  64: round up from x.75
@@ -2469,7 +2469,7 @@
 /** Include the header given by LV_ATTRIBUTE_CUSTOM_INCLUDE to override the
  *  LV_ATTRIBUTE_* macros for your platform.
  */
-#define LV_ATTRIBUTE_USE_CUSTOM_INCLUDE 0
+#define LV_ATTRIBUTE_USE_CUSTOM_INCLUDE 1
 
 #if LV_ATTRIBUTE_USE_CUSTOM_INCLUDE
 /** Optional header to override LV_ATTRIBUTE_* macros for your platform.
@@ -2527,7 +2527,7 @@
  *    Leave undefined if not using a binding.
  *    e.g. mp_rom_map_elem_t entry = {MP_ROM_QSTR(MP_QSTR_##int_value), MP_ROM_INT(int_value)}
  */
-#define LV_ATTRIBUTE_CUSTOM_INCLUDE ""
+#define LV_ATTRIBUTE_CUSTOM_INCLUDE "lv_attr_jc3636w518.h"  /* JC3636W518: IRAM placement */
 
 #endif /*LV_ATTRIBUTE_USE_CUSTOM_INCLUDE*/