Merge pull request #333 from andrewjswan/fix-esphome-2026.4

Fix distorted animated icons on ESPHome 2026.4.0 (#331)

Author: lubeda

components/ehmtxv2/__init__.py

@@ -13,7 +13,7 @@
 from esphome.const import CONF_BLUE, CONF_GREEN, CONF_RED, CONF_RESIZE, CONF_FILE, CONF_ID, CONF_BRIGHTNESS, CONF_RAW_DATA_ID,  CONF_TIME, CONF_TRIGGER_ID
 from esphome.core import CORE, HexInt
 from esphome.cpp_generator import RawExpression
-from esphome.components.image import CONF_ALPHA_CHANNEL, IMAGE_TYPE
+from esphome.components.image import CONF_CHROMA_KEY, IMAGE_TYPE
 
 from urllib.parse import urlparse
 
@@ -484,7 +484,15 @@ def openImageFile(path):
             yaml_string += F"\"{conf[CONF_ID]}\","
 
             dither = Image.Dither.NONE
-            transparency = CONF_ALPHA_CHANNEL
+            # Use CHROMA_KEY instead of ALPHA_CHANNEL: on ESPHome 2026.4.0 the
+            # appended-alpha layout is incompatible with Animation frame indexing
+            # (Animation::update_data_start_ advances by w*h*2 per frame, ignoring
+            # the alpha block). Chroma-key stores the transparent-pixel marker
+            # inline (0x0020), so each frame is exactly w*h*2 bytes and the C++
+            # Animation class can index into it correctly on every ESPHome
+            # version. 8x8 pixel-art icons use binary transparency anyway —
+            # fixes issue #331.            
+            transparency = CONF_CHROMA_KEY
             invert_alpha = False
 
             total_rows = height * frames
@@ -495,6 +503,12 @@ def openImageFile(path):
                 dither,
                 invert_alpha,
             )
+            # ESPHome 2026.4.0 flipped the default RGB565 byte order to little-
+            # endian, but the C++ Image::get_rgb565_pixel_ decoder still reads
+            # big-endian. set_big_endian exists on every ESPHome release that
+            # supports EHMTXv2; no-op on <2026.4.0 where BE was already default.
+            if hasattr(encoder, "set_big_endian"):
+                encoder.set_big_endian(True)
             for frame_index in range(frames):
                 image.seek(frame_index)
                 pixels = encoder.convert(image.resize((width, height)), path).getdata()