From a379e5a6357340a696d9cbc67a8ad48a0bad0924 Mon Sep 17 00:00:00 2001
From: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
Date: Mon, 9 Mar 2026 17:16:29 -0400
Subject: [PATCH] [runtime_image][st7701s] Fix BMP decoder and LCD init bugs
 (#14663)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../components/runtime_image/bmp_decoder.cpp   | 18 +++++++++++++++---
 esphome/components/st7701s/st7701s.cpp         |  6 ++++--
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/esphome/components/runtime_image/bmp_decoder.cpp b/esphome/components/runtime_image/bmp_decoder.cpp
index 1a56484c606..7003f4da2ff 100644
--- a/esphome/components/runtime_image/bmp_decoder.cpp
+++ b/esphome/components/runtime_image/bmp_decoder.cpp
@@ -63,7 +63,8 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
 
     switch (this->bits_per_pixel_) {
       case 1:
-        this->width_bytes_ = (this->width_ % 8 == 0) ? (this->width_ / 8) : (this->width_ / 8 + 1);
+        this->width_bytes_ = (this->width_ + 7) / 8;
+        this->padding_bytes_ = (4 - (this->width_bytes_ % 4)) % 4;
         break;
       case 24:
         this->width_bytes_ = this->width_ * 3;
@@ -92,15 +93,26 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
     case 1: {
       while (index < size) {
         uint8_t current_byte = buffer[index];
+        bool end_of_row = false;
         for (uint8_t i = 0; i < 8; i++) {
-          size_t x = (this->paint_index_ % static_cast<size_t>(this->width_)) + i;
+          size_t x = this->paint_index_ % static_cast<size_t>(this->width_);
           size_t y = static_cast<size_t>(this->height_ - 1) - (this->paint_index_ / static_cast<size_t>(this->width_));
           Color c = (current_byte & (1 << (7 - i))) ? display::COLOR_ON : display::COLOR_OFF;
           this->draw(x, y, 1, 1, c);
+          this->paint_index_++;
+          // End of pixel row: skip remaining bits in this byte
+          if (x + 1 >= static_cast<size_t>(this->width_)) {
+            end_of_row = true;
+            break;
+          }
         }
-        this->paint_index_ += 8;
         this->current_index_++;
         index++;
+        // End of pixel row: skip row padding bytes (4-byte alignment)
+        if (end_of_row && this->padding_bytes_ > 0) {
+          index += this->padding_bytes_;
+          this->current_index_ += this->padding_bytes_;
+        }
       }
       break;
     }
diff --git a/esphome/components/st7701s/st7701s.cpp b/esphome/components/st7701s/st7701s.cpp
index 221fe39b9d8..ecce4eb4b27 100644
--- a/esphome/components/st7701s/st7701s.cpp
+++ b/esphome/components/st7701s/st7701s.cpp
@@ -36,11 +36,13 @@ void ST7701S::setup() {
   config.de_gpio_num = this->de_pin_->get_pin();
   config.pclk_gpio_num = this->pclk_pin_->get_pin();
   esp_err_t err = esp_lcd_new_rgb_panel(&config, &this->handle_);
-  ESP_ERROR_CHECK(esp_lcd_panel_reset(this->handle_));
-  ESP_ERROR_CHECK(esp_lcd_panel_init(this->handle_));
   if (err != ESP_OK) {
     esph_log_e(TAG, "lcd_new_rgb_panel failed: %s", esp_err_to_name(err));
+    this->mark_failed();
+    return;
   }
+  ESP_ERROR_CHECK(esp_lcd_panel_reset(this->handle_));
+  ESP_ERROR_CHECK(esp_lcd_panel_init(this->handle_));
 }
 
 void ST7701S::loop() {