diff options
| -rw-r--r-- | TurtleArt/tacanvas.py | 44 |
1 files changed, 35 insertions, 9 deletions
diff --git a/TurtleArt/tacanvas.py b/TurtleArt/tacanvas.py index 0f110bf..d0b58e2 100644 --- a/TurtleArt/tacanvas.py +++ b/TurtleArt/tacanvas.py @@ -42,18 +42,29 @@ def wrap100(n): return n -def calc_shade(c, s): +def calc_shade(c, s, invert=False): """ Convert a color to the current shade (lightness/darkness). """ - if s < 0: - return int(c * (1 + s * 0.8)) - return int(c + (65536 - c) * s * 0.9) - - -def calc_gray(c, g): + # Assumes 16 bit input values + if invert: + if s < 0: + return int(c / (1 + s * 0.8)) + return int((c - 65536 * s * 0.9) / (1 - (s * 0.9))) + else: + if s < 0: + return int(c * (1 + s * 0.8)) + return int(c + (65536 - c) * s * 0.9) + + +def calc_gray(c, g, invert=False): """ Gray is a psuedo saturation calculation. """ + # Assumes 16 bit input values if g == 100: return c - return int(((c * g) + (32768 * (100 - g))) / 100) + if invert: + return int(((c * 100) - (32768 * (100 - g))) / g) + else: + return int(((c * g) + (32768 * (100 - g))) / 100) + colors = {} DEGTOR = 2 * pi / 360 @@ -568,7 +579,22 @@ class TurtleGraphics: def get_color_index(self, r, g, b, a=0): """ Find the closest palette entry to the rgb triplet """ - # TODO: Take into account gray and shade levels + if self.shade != 50 or self.gray != 100: + r <<= 8 + g <<= 8 + b <<= 8 + if self.shade != 50: + sh = (wrap100(self.shade) - 50) / 50.0 + r = calc_shade(r, sh, True) + g = calc_shade(g, sh, True) + b = calc_shade(b, sh, True) + if self.gray != 100: + r = calc_gray(r, self.gray, True) + g = calc_gray(g, self.gray, True) + b = calc_gray(b, self.gray, True) + r >>= 8 + g >>= 8 + b >>= 8 min_distance = 1000000 closest_color = -1 for i, c in enumerate(color_table): |