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103 lines
2.8 KiB
Python
103 lines
2.8 KiB
Python
# igc2kmz/color.py igc2kmz color functions
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# Copyright (C) 2008 Tom Payne
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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def hsl_to_rgba(hsl, a=1.0):
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"""Convert a HSL tuple into a RGBA tuple."""
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def h_to_value(p, q, t):
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if t < 0.0:
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t += 1.0
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elif 1.0 < t:
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t -= 1.0
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if t < 1.0 / 6.0:
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return p + 6.0 * (q - p) * t
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elif t < 0.5:
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return q
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elif t < 2.0 / 3.0:
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return p + 6.0 * (q - p) * (2.0 / 3.0 - t)
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else:
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return p
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h, s, l = hsl
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if s == 0:
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return (l, l, l, a)
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if l < 0.5:
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q = l * (s + 1.0)
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else:
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q = l + s - l * s
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p = 2.0 * l - q
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r = h_to_value(p, q, h + 1.0 / 3.0)
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g = h_to_value(p, q, h)
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b = h_to_value(p, q, h - 1.0 / 3.0)
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return (r, g, b, a)
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def hsv_to_rgb(hsv):
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"""Convert a HSV tuple into a RGBA tuple."""
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h, s, v = hsv
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hi = int(h)
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f = h - hi
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p = v * (1.0 - f)
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q = v * (1.0 - f * s)
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t = v * (1.0 - (1.0 - f) * s)
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if hi == 0:
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return (v, t, p)
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elif hi == 1:
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return (q, v, p)
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elif hi == 2:
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return (p, v, t)
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elif hi == 3:
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return (p, q, v)
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elif hi == 4:
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return (t, p, v)
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else:
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return (v, p, q)
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def grayscale_gradient(value):
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"""Return a gradient from black to white."""
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if value < 0.0:
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return (0.0, 0.0, 0.0, 1.0)
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elif 1.0 <= value:
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return (1.0, 1.0, 1.0, 1.0)
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else:
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return (value, value, value, 1.0)
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def default_gradient(value):
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"""Return a gradient from blue to green to red."""
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if value < 0.0:
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return hsl_to_rgba((2.0 / 3.0, 1.0, 0.5))
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elif 1.0 <= value:
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return hsl_to_rgba((0.0, 1.0, 0.5))
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else:
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h = 2.0 * (1.0 - value) / 3.0
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return hsl_to_rgba((h, 1.0, 0.5))
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def bilinear_gradient(value):
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"""Return a bilinear gradient from blue to green to red."""
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if value < 0.0:
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h = 2.0 / 3.0
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elif value < 0.5:
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h = (6.0 - 4.0 * value) / 9.0
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elif value == 0.5:
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h = 1.0 / 3.0
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elif value < 1.0:
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h = (4.0 - 4.0 * value) / 9.0
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else:
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h = 0.0
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return hsl_to_rgba((h, 1.0, 0.5))
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