ii-pix/palette.py
2021-11-02 15:45:20 +00:00

147 lines
4.9 KiB
Python

"""RGB colour palettes to target for Apple II image conversions."""
import colour
import numpy as np
import image
import palette_ntsc
class Palette:
SRGB = None
RGB = {}
CAM16UCS = {}
# How many successive screen pixels are used to compute output pixel
# palette index.
PALETTE_DEPTH = None
def __init__(self):
self.RGB = {}
# XXX RGB and CAM16UCS should be indexed by (pixels_nbit, phase)
for k, v in self.SRGB.items():
self.RGB[k] = (np.clip(image.srgb_to_linear_array(v / 255), 0.0,
1.0) * 255).astype(np.uint8)
with colour.utilities.suppress_warnings(colour_usage_warnings=True):
self.CAM16UCS[k] = colour.convert(
v / 255, "sRGB", "CAM16UCS").astype(np.float32)
def _pixel_phase_shifts(self, phase_0_rgb):
rgb_phases = {}
for pixels, rgb in phase_0_rgb.items():
rgb_phases[pixels, 0] = rgb
for phase in range(1, 4):
msb = pixels & (1 << (self.PALETTE_DEPTH - 1))
pixels <<= 1 | (msb >> (self.PALETTE_DEPTH - 1))
rgb_phases[pixels, phase] = rgb
return rgb_phases
def bitmap_to_idx(self, pixels: np.array) -> int:
"""Converts a bitmap of pixels into integer representation.
Args:
pixels: 1-D array of booleans, representing a window of pixels from
L to R. Must be of size <= 8
Returns:
8-bit integer representation of pixels, suitable for use as an
index into palette arrays
"""
return np.packbits(
# numpy uses big-endian representation which is the opposite
# order to screen representation (i.e. LSB is the left-most
# screen pixel), so we need to flip the order
np.flip(pixels, axis=0)
)[0]
class ToHgrPalette(Palette):
"""4-bit palette used as default by other DHGR image converters."""
PALETTE_DEPTH = 4
# Default tohgr/bmp2dhr palette
SRGB = {
0: np.array((0, 0, 0)), # Black
8: np.array((148, 12, 125)), # Magenta
4: np.array((99, 77, 0)), # Brown
12: np.array((249, 86, 29)), # Orange
2: np.array((51, 111, 0)), # Dark green
10: np.array((126, 126, 126)), # Grey2
6: np.array((67, 200, 0)), # Green
14: np.array((221, 206, 23)), # Yellow
1: np.array((32, 54, 212)), # Dark blue
9: np.array((188, 55, 255)), # Violet
5: np.array((126, 126, 126)), # Grey1
13: np.array((255, 129, 236)), # Pink
3: np.array((7, 168, 225)), # Med blue
11: np.array((158, 172, 255)), # Light blue
7: np.array((93, 248, 133)), # Aqua
15: np.array((255, 255, 255)), # White
}
class OpenEmulatorPalette(Palette):
"""4-bit palette chosen to approximately match OpenEmulator output."""
PALETTE_DEPTH = 4
# OpenEmulator
SRGB = {
0: np.array((0, 0, 0)), # Black
8: np.array((203, 0, 121)), # Magenta
4: np.array((99, 103, 0)), # Brown
12: np.array((244, 78, 0)), # Orange
2: np.array((0, 150, 0)), # Dark green
10: np.array((130, 130, 130)), # Grey2
6: np.array((0, 235, 0)), # Green
14: np.array((214, 218, 0)), # Yellow
1: np.array((20, 0, 246)), # Dark blue
9: np.array((230, 0, 244)), # Violet
5: np.array((130, 130, 130)), # Grey1
13: np.array((244, 105, 235)), # Pink
3: np.array((0, 174, 243)), # Med blue
11: np.array((160, 156, 244)), # Light blue
7: np.array((25, 243, 136)), # Aqua
15: np.array((244, 247, 244)), # White
}
class VirtualIIPalette(Palette):
"""4-bit palette exactly matching Virtual II emulator output."""
PALETTE_DEPTH = 4
SRGB = {
0: np.array((0, 0, 0)), # Black
8: np.array((231, 36, 66)), # Magenta
4: np.array((154, 104, 0)), # Brown
12: np.array((255, 124, 0)), # Orange
2: np.array((0, 135, 45)), # Dark green
10: np.array((104, 104, 104)), # Grey2
6: np.array((0, 222, 0)), # Green
14: np.array((255, 252, 0)), # Yellow
1: np.array((1, 30, 169)), # Dark blue
9: np.array((230, 73, 228)), # Violet
5: np.array((185, 185, 185)), # Grey1
13: np.array((255, 171, 153)), # Pink
3: np.array((47, 69, 255)), # Med blue
11: np.array((120, 187, 255)), # Light blue
7: np.array((83, 250, 208)), # Aqua
15: np.array((255, 255, 255)), # White
}
class NTSCPalette(Palette):
"""8-bit NTSC palette computed by averaging chroma signal over 8 pixels."""
PALETTE_DEPTH = 8
# Computed using ntsc_colours.py
SRGB = palette_ntsc.SRGB
PALETTES = {
'openemulator': OpenEmulatorPalette,
'virtualii': VirtualIIPalette,
'tohgr': ToHgrPalette,
'ntsc': NTSCPalette
}
DEFAULT_PALETTE = 'ntsc'