From c559ccbb831d1afd19863151fd3fa42a489dda48 Mon Sep 17 00:00:00 2001
From: Clyde Stubbs <2366188+clydebarrow@users.noreply.github.com>
Date: Mon, 11 Mar 2024 16:52:05 +1100
Subject: [PATCH] ILI9XXX: Lazily allocate buffer (#6352)

---
 esphome/components/ili9xxx/ili9xxx_display.cpp | 7 ++++++-
 esphome/components/ili9xxx/ili9xxx_display.h   | 9 +++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/esphome/components/ili9xxx/ili9xxx_display.cpp b/esphome/components/ili9xxx/ili9xxx_display.cpp
index 9f06c9ce0f..e292906a93 100644
--- a/esphome/components/ili9xxx/ili9xxx_display.cpp
+++ b/esphome/components/ili9xxx/ili9xxx_display.cpp
@@ -42,7 +42,9 @@ void ILI9XXXDisplay::setup() {
   this->y_low_ = this->height_;
   this->x_high_ = 0;
   this->y_high_ = 0;
+}
 
+void ILI9XXXDisplay::alloc_buffer_() {
   if (this->buffer_color_mode_ == BITS_16) {
     this->init_internal_(this->get_buffer_length_() * 2);
     if (this->buffer_ != nullptr) {
@@ -107,6 +109,8 @@ void ILI9XXXDisplay::dump_config() {
 float ILI9XXXDisplay::get_setup_priority() const { return setup_priority::HARDWARE; }
 
 void ILI9XXXDisplay::fill(Color color) {
+  if (!this->check_buffer_())
+    return;
   uint16_t new_color = 0;
   this->x_low_ = 0;
   this->y_low_ = 0;
@@ -124,7 +128,6 @@ void ILI9XXXDisplay::fill(Color color) {
           // Upper and lower is equal can use quicker memset operation. Takes ~20ms.
           memset(this->buffer_, (uint8_t) new_color, buffer_length_16_bits);
         } else {
-          // Slower set of both buffers. Takes ~30ms.
           for (uint32_t i = 0; i < buffer_length_16_bits; i = i + 2) {
             this->buffer_[i] = (uint8_t) (new_color >> 8);
             this->buffer_[i + 1] = (uint8_t) new_color;
@@ -144,6 +147,8 @@ void HOT ILI9XXXDisplay::draw_absolute_pixel_internal(int x, int y, Color color)
   if (x >= this->get_width_internal() || x < 0 || y >= this->get_height_internal() || y < 0) {
     return;
   }
+  if (!this->check_buffer_())
+    return;
   uint32_t pos = (y * width_) + x;
   uint16_t new_color;
   bool updated = false;
diff --git a/esphome/components/ili9xxx/ili9xxx_display.h b/esphome/components/ili9xxx/ili9xxx_display.h
index 7cbdb4569a..41a1bbb528 100644
--- a/esphome/components/ili9xxx/ili9xxx_display.h
+++ b/esphome/components/ili9xxx/ili9xxx_display.h
@@ -86,6 +86,14 @@ class ILI9XXXDisplay : public display::DisplayBuffer,
                       display::ColorBitness bitness, bool big_endian, int x_offset, int y_offset, int x_pad) override;
 
  protected:
+  inline bool check_buffer_() {
+    if (this->buffer_ == nullptr) {
+      this->alloc_buffer_();
+      return !this->is_failed();
+    }
+    return true;
+  }
+
   void draw_absolute_pixel_internal(int x, int y, Color color) override;
   void setup_pins_();
 
@@ -116,6 +124,7 @@ class ILI9XXXDisplay : public display::DisplayBuffer,
   void end_command_();
   void start_data_();
   void end_data_();
+  void alloc_buffer_();
 
   GPIOPin *reset_pin_{nullptr};
   GPIOPin *dc_pin_{nullptr};