First public commit.

lenser/iigs/convert/mono.py

@@ -0,0 +1,25 @@
+"""Apple IIGS SHR monochrome: 320x200 with a single 16-level grey palette (the
+richest greyscale in lenser).  ``--mono-base`` tints the ramp toward a colour."""
+from __future__ import annotations
+
+from ...convert.base import Conversion
+from ...palette import get_palette
+from . import _common
+
+WIDTH, HEIGHT = 320, 200
+PIXEL_ASPECT = 1.0
+
+
+def convert(img_rgb, palette_name="iigs", dither_mode="floyd",
+            intensive=False, base_color=None):
+    base_rgb = None
+    if isinstance(base_color, int) and 0 <= base_color < 16:
+        base_rgb = get_palette("colodore")[base_color]      # tint hue from C64 pal
+    block, preview, err = _common.encode(img_rgb, dither_mode, mono=True,
+                                         base_color=base_rgb)
+    return Conversion(
+        mode="mono", width=WIDTH, height=HEIGHT, pixel_aspect=PIXEL_ASPECT,
+        index_image=None, data=block, data_addr=0x2000, viewer="iigs",
+        preview_rgb=preview, error=err,
+        meta={"palette": "iigs", "dither": dither_mode},
+    )