40 lines
1.5 KiB
Python
40 lines
1.5 KiB
Python
"""Atari GR.8 (ANTIC mode F): 320x192 hi-res, two tones of one hue.
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Highest spatial resolution; carries tone by dithering between background and a
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foreground luminance. ``base_color`` picks the hue (None = greyscale).
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"""
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from __future__ import annotations
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import numpy as np
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from ...convert.base import Conversion, perceptual_error
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from .. import palette as apal
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from . import _common
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WIDTH, HEIGHT = 320, 192
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PIXEL_ASPECT = 1.0
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def convert(img_rgb, palette_name="ntsc", dither_mode="floyd",
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intensive=False, base_color=None):
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hue = 0 if base_color is None else (int(base_color) & 0x0F)
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bg_reg = (hue << 4) | 0x00 # darkest of the hue
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fg_reg = (hue << 4) | 0x0E # brightest of the hue
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plab = apal.palette_lab(palette_name)
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prgb = apal.get_palette(palette_name).astype(np.uint8)
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img_mono, plab_mono = _common.luminance_lab(img_rgb, plab)
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idx = _common.quantize_global(img_mono, plab_mono, [bg_reg, fg_reg], dither_mode)
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val = (idx == fg_reg).astype(np.uint8)
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data = _common.split_screen(_common.pack_1bpp(val)) + bytes([bg_reg, fg_reg])
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preview = prgb[idx] # already 320 wide
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return Conversion(
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mode="gr8", width=WIDTH, height=HEIGHT, pixel_aspect=PIXEL_ASPECT,
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index_image=idx.astype(np.uint16), data=data, data_addr=_common.DATA_ADDR,
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viewer="gr8", preview_rgb=preview,
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error=perceptual_error(idx, img_mono, plab_mono),
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meta={"palette": palette_name, "dither": dither_mode, "hue": hue},
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)
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