fix: per-panel BWRY code table + 4-gray table additions (M3)

src/opendisplay/device.py

@@ -19,11 +19,12 @@
     encrypt_command,
     generate_client_nonce,
 )
-from .display_palettes import PANELS_4GRAY, get_gray4_codes, get_palette_for_display
+from .display_palettes import PANELS_4GRAY, get_bwry_codes, get_gray4_codes, get_palette_for_display
 from .encoding import (
     DEFAULT_ZLIB_WINDOW_BITS,
     ZIPXL_ZLIB_WINDOW_BITS,
     compress_image_data,
+    encode_2bpp,
     encode_bitplanes,
     encode_gray4_bitplanes,
     encode_image,
@@ -250,6 +251,11 @@ def prepare_image(
     elif color_scheme == ColorScheme.GRAYSCALE_4:
         # Two pre-split 1-bit planes concatenated; firmware streams the halves to PLANE_0/PLANE_1.
         image_data = b"".join(encode_gray4_bitplanes(dithered, get_gray4_codes(panel_ic_type)))
+    elif color_scheme == ColorScheme.BWRY:
+        # Some YR panels (0x001D/0x001E) use a native 4-color code order with
+        # yellow/red swapped relative to the dither palette; apply the per-panel
+        # code table so the firmware's raw-nibble direct write shows the right color.
+        image_data = encode_2bpp(dithered, codes=get_bwry_codes(panel_ic_type))
     else:
         image_data = encode_image(dithered, color_scheme)
 

src/opendisplay/display_palettes.py

@@ -20,6 +20,11 @@
         0x002F,  # EP29Z_128x296_4GRAY
         0x0031,  # EP213Z_122x250_4GRAY
         0x003C,  # EP75_800x480_4GRAY_GEN2
+        0x0043,  # newer 4-gray panel
+        0x0044,  # newer 4-gray panel
+        0x0046,  # newer 4-gray panel
+        0x0048,  # EP368_792x528_4GRAY
+        0x004C,  # newer 4-gray panel
     }
 )
 
@@ -31,6 +36,7 @@
 _GRAY4_CODES_V2: tuple[int, int, int, int] = (3, 2, 1, 0)  # u8Colors_4gray_v2
 _GRAY4_CODES_BY_PANEL: dict[int, tuple[int, int, int, int]] = {
     0x0028: _GRAY4_CODES_V2,  # EP426_800x480_4GRAY
+    0x0048: _GRAY4_CODES_V2,  # EP368_792x528_4GRAY
 }
 
 
@@ -41,6 +47,27 @@ def get_gray4_codes(panel_ic_type: int | None) -> tuple[int, int, int, int]:
     return _GRAY4_CODES_BY_PANEL.get(panel_ic_type, _GRAY4_CODES_BASE)
 
 
+# Per-panel BWRY palette-index -> stored-nibble tables, mirroring bb_epaper's
+# 4-color swatch tables (bb_ep.inl). The dither palette orders indices as
+# black=0, white=1, yellow=2, red=3. Most YR panels use u8Colors_4clr_v2, whose
+# native codes match that order. Panels 0x001D/0x001E use u8Colors_4clr, where
+# native code 2=red and 3=yellow, so yellow/red must be swapped on the wire
+# (the firmware direct-write path streams the nibble raw).
+_BWRY_CODES_DEFAULT: tuple[int, int, int, int] = (0, 1, 2, 3)  # u8Colors_4clr_v2
+_BWRY_CODES_SWAPPED: tuple[int, int, int, int] = (0, 1, 3, 2)  # u8Colors_4clr
+_BWRY_CODES_BY_PANEL: dict[int, tuple[int, int, int, int]] = {
+    0x001D: _BWRY_CODES_SWAPPED,  # EP29YR_128x296
+    0x001E: _BWRY_CODES_SWAPPED,  # EP29YR_168x384
+}
+
+
+def get_bwry_codes(panel_ic_type: int | None) -> tuple[int, int, int, int]:
+    """Return the BWRY palette-index->stored-nibble table for a panel."""
+    if panel_ic_type is None:
+        return _BWRY_CODES_DEFAULT
+    return _BWRY_CODES_BY_PANEL.get(panel_ic_type, _BWRY_CODES_DEFAULT)
+
+
 # Map: (panel_ic_type, color_scheme) -> measured ColorPalette
 # panel_ic_type identifies the e-paper panel model
 # color_scheme identifies the color mode (MONO, BWR, BWGBRY, etc.)

src/opendisplay/encoding/images.py

@@ -128,14 +128,17 @@ def encode_1bpp(image: Image.Image) -> bytes:
     return bytes(output)
 
 
-def encode_2bpp(image: Image.Image) -> bytes:
+def encode_2bpp(image: Image.Image, codes: tuple[int, int, int, int] | None = None) -> bytes:
     """Encode image to 2-bits-per-pixel format (4 colors).
 
     Format: 4 pixels per byte, MSB first
     Each 2-bit value maps to palette index (0-3)
 
     Args:
         image: Palette image (mode 'P')
+        codes: Optional palette-index -> stored-nibble table. Used by BWRY panels
+            whose native 4-color code order differs from the dither palette order
+            (e.g. yellow/red swapped). Defaults to identity.
 
     Returns:
         Encoded bytes
@@ -157,6 +160,8 @@ def encode_2bpp(image: Image.Image) -> bytes:
             bit_shift = (3 - pixel_in_byte) * 2  # MSB first
 
             palette_idx = pixels[y, x] & 0x03  # 2-bit value
+            if codes is not None:
+                palette_idx = codes[palette_idx]
             output[byte_idx] |= palette_idx << bit_shift
 
     return bytes(output)

tests/unit/test_bwry_panel_palette.py

@@ -0,0 +1,40 @@
+"""Tests for per-panel BWRY code tables and 4-gray table additions (M3)."""
+
+from __future__ import annotations
+
+from PIL import Image
+
+from opendisplay.display_palettes import (
+    PANELS_4GRAY,
+    get_bwry_codes,
+    get_gray4_codes,
+)
+from opendisplay.encoding.images import encode_2bpp
+
+
+def test_get_bwry_codes_swaps_yellow_red_on_u8colors_4clr_panels() -> None:
+    assert get_bwry_codes(0x001D) == (0, 1, 3, 2)
+    assert get_bwry_codes(0x001E) == (0, 1, 3, 2)
+
+
+def test_get_bwry_codes_default_is_identity() -> None:
+    assert get_bwry_codes(55) == (0, 1, 2, 3)
+    assert get_bwry_codes(None) == (0, 1, 2, 3)
+
+
+def test_encode_2bpp_applies_code_table() -> None:
+    img = Image.new("P", (4, 1))
+    img.putdata([0, 1, 2, 3])  # black, white, yellow, red
+
+    # identity: 0b00_01_10_11
+    assert encode_2bpp(img) == bytes([0b00011011])
+    # yellow/red swapped: 0b00_01_11_10
+    assert encode_2bpp(img, codes=(0, 1, 3, 2)) == bytes([0b00011110])
+
+
+def test_gray4_v2_table_includes_ep368() -> None:
+    assert get_gray4_codes(0x0048) == (3, 2, 1, 0)
+
+
+def test_panels_4gray_includes_new_ids() -> None:
+    assert {0x0043, 0x0044, 0x0046, 0x0048, 0x004C} <= PANELS_4GRAY