First public commit.

lenser/cpc/convert/mode1.py

@@ -0,0 +1,22 @@
+"""CPC Mode 1: 320x200, 4 colours from the 27-colour palette (more resolution,
+fewer colours than mode 0)."""
+from __future__ import annotations
+
+from ...convert.base import Conversion, perceptual_error
+from . import _common
+
+WIDTH, HEIGHT = 320, 200
+PIXEL_ASPECT = 1.0
+NCOL = 4
+
+
+def convert(img_rgb, palette_name="cpc", dither_mode="floyd",
+            intensive=False, base_color=None):
+    pen, inks, idx, img_lab, plab, prgb = _common.render(img_rgb, NCOL, dither_mode)
+    screen = _common.PACK[1](pen)
+    return Conversion(
+        mode="mode1", width=WIDTH, height=HEIGHT, pixel_aspect=PIXEL_ASPECT,
+        index_image=idx, data=screen, data_addr=0xC000, viewer="cpc",
+        preview_rgb=prgb[idx], error=perceptual_error(idx, img_lab, plab),
+        meta={"palette": "cpc", "dither": dither_mode, "cpc_mode": 1, "inks": inks},
+    )