mirror of
https://github.com/KrisKennaway/ii-pix.git
synced 2024-11-19 08:30:48 +00:00
8b500b16cb
This gives the best of both worlds: dithering in a linear space, with good (and fast) perceptual error differences TBD: would linear RGB work as well as XYZ?
147 lines
5.1 KiB
Python
147 lines
5.1 KiB
Python
"""RGB colour palettes to target for Apple II image conversions."""
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import colour
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import numpy as np
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import image
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import palette_ntsc
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class Palette:
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RGB = {}
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SRGB = None
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CAM16UCS = {}
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XYZ = {}
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DOTS = {}
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DOTS_TO_INDEX = {}
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DISTANCES_PATH = None
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# How many successive screen pixels are used to compute output pixel
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# palette index.
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PALETTE_DEPTH = None
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def __init__(self, load_distances=True):
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# if load_distances:
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# # CIE2000 colour distance matrix from 24-bit RGB tuple to 4-bit
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# # palette colour.
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# self.distances = np.memmap(self.DISTANCES_PATH, mode="r+",
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# dtype=np.uint8, shape=(16777216,
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# len(self.SRGB)))
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self.RGB = {}
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for k, v in self.SRGB.items():
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self.RGB[k] = (np.clip(image.srgb_to_linear_array(v / 255), 0.0,
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1.0) * 255).astype(np.uint8)
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self.CAM16UCS[k] = colour.convert(v / 255, "sRGB",
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"CAM16UCS").astype(np.float32)
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self.XYZ[k] = colour.convert(v / 255, "sRGB",
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"CIE XYZ").astype(np.float32)
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# print(self.CAM02UCS)
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# Maps palette values to screen dots. Note that these are the same as
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# the binary index values in reverse order.
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for i in range(1 << self.PALETTE_DEPTH):
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self.DOTS[i] = tuple(
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bool(i & (1 << j)) for j in range(self.PALETTE_DEPTH))
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# Reverse mapping from screen dots to palette index.
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self.DOTS_TO_INDEX = {}
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for k, v in self.DOTS.items():
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self.DOTS_TO_INDEX[v] = k
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# class ToHgrPalette(Palette):
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# """4-bit palette used as default by other DHGR image converters."""
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# DISTANCES_PATH = "data/distances_tohgr.data"
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# PALETTE_DEPTH = 4
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#
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# # Default tohgr/bmp2dhr palette
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# SRGB = {
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# 0: np.array((0, 0, 0)), # Black
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# 8: np.array((148, 12, 125)), # Magenta
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# 4: np.array((99, 77, 0)), # Brown
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# 12: np.array((249, 86, 29)), # Orange
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# 2: np.array((51, 111, 0)), # Dark green
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# 10: np.array((126, 126, 126)), # Grey2
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# 6: np.array((67, 200, 0)), # Green
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# 14: np.array((221, 206, 23)), # Yellow
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# 1: np.array((32, 54, 212)), # Dark blue
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# 9: np.array((188, 55, 255)), # Violet
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# 5: np.array((126, 126, 126)), # Grey1
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# 13: np.array((255, 129, 236)), # Pink
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# 3: np.array((7, 168, 225)), # Med blue
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# 11: np.array((158, 172, 255)), # Light blue
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# 7: np.array((93, 248, 133)), # Aqua
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# 15: np.array((255, 255, 255)), # White
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# }
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#
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#
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# class OpenEmulatorPalette(Palette):
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# """4-bit palette chosen to approximately match OpenEmulator output."""
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# DISTANCES_PATH = "data/distances_openemulator.data"
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# PALETTE_DEPTH = 4
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#
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# # OpenEmulator
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# SRGB = {
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# 0: np.array((0, 0, 0)), # Black
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# 8: np.array((203, 0, 121)), # Magenta
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# 4: np.array((99, 103, 0)), # Brown
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# 12: np.array((244, 78, 0)), # Orange
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# 2: np.array((0, 150, 0)), # Dark green
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# 10: np.array((130, 130, 130)), # Grey2
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# 6: np.array((0, 235, 0)), # Green
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# 14: np.array((214, 218, 0)), # Yellow
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# 1: np.array((20, 0, 246)), # Dark blue
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# 9: np.array((230, 0, 244)), # Violet
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# 5: np.array((130, 130, 130)), # Grey1
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# 13: np.array((244, 105, 235)), # Pink
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# 3: np.array((0, 174, 243)), # Med blue
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# 11: np.array((160, 156, 244)), # Light blue
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# 7: np.array((25, 243, 136)), # Aqua
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# 15: np.array((244, 247, 244)), # White
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# }
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#
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#
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# class VirtualIIPalette(Palette):
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# """4-bit palette exactly matching Virtual II emulator output."""
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# DISTANCES_PATH = "data/distances_virtualii.data"
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# PALETTE_DEPTH = 4
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#
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# SRGB = {
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# 0: np.array((0, 0, 0)), # Black
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# 8: np.array((231, 36, 66)), # Magenta
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# 4: np.array((154, 104, 0)), # Brown
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# 12: np.array((255, 124, 0)), # Orange
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# 2: np.array((0, 135, 45)), # Dark green
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# 10: np.array((104, 104, 104)), # Grey2
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# 6: np.array((0, 222, 0)), # Green
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# 14: np.array((255, 252, 0)), # Yellow
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# 1: np.array((1, 30, 169)), # Dark blue
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# 9: np.array((230, 73, 228)), # Violet
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# 5: np.array((185, 185, 185)), # Grey1
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# 13: np.array((255, 171, 153)), # Pink
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# 3: np.array((47, 69, 255)), # Med blue
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# 11: np.array((120, 187, 255)), # Light blue
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# 7: np.array((83, 250, 208)), # Aqua
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# 15: np.array((255, 255, 255)), # White
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# }
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class NTSCPalette(Palette):
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"""8-bit NTSC palette computed by averaging chroma signal over 8 pixels."""
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DISTANCES_PATH = 'data/distances_ntsc.data'
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PALETTE_DEPTH = 8
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# Computed using ntsc_colours.py
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SRGB = palette_ntsc.SRGB
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PALETTES = {
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# 'openemulator': OpenEmulatorPalette,
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# 'virtualii': VirtualIIPalette,
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# 'tohgr': ToHgrPalette,
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'ntsc': NTSCPalette
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}
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DEFAULT_PALETTE = 'ntsc'
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