diff options
| -rw-r--r-- | src/curve.py | 161 |
1 files changed, 126 insertions, 35 deletions
diff --git a/src/curve.py b/src/curve.py index 4be11fc..7efb26e 100644 --- a/src/curve.py +++ b/src/curve.py @@ -14,6 +14,10 @@ # # You should have received a copy of the GNU Affero General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. + +# This module contains the colour curve definitions and functions for +# manipulating the colour curves + import math from colour import * @@ -68,8 +72,9 @@ def rgb_temperature(temperature, algorithm): @param temperature:float The blackbody temperature in kelvins @param algorithm:(float)→(float, float, float) Algorithm for calculating a white point, for example `cmf_10deg` ''' - if temperature == 6500: - return + # Do nothing if the temperature is neutral + if temperature == 6500: return + # Otherwise manipulate the colour curves rgb_brightness(*(algorithm(temperature))) @@ -80,8 +85,9 @@ def cie_temperature(temperature, algorithm): @param temperature:float The blackbody temperature in kelvins @param algorithm:(float)→(float, float, float) Algorithm for calculating a white point, for example `cmf_10deg` ''' - if temperature == 6500: - return + # Do nothing if the temperature is neutral + if temperature == 6500: return + # Otherwise manipulate the colour curves cie_brightness(*(algorithm(temperature))) @@ -89,37 +95,54 @@ def rgb_contrast(r, g = ..., b = ...): ''' Apply contrast correction on the colour curves using sRGB + In this context, contrast is a measure of difference between the whitepoint and blackpoint, + if the difference is 0 than they are both grey + @param r:float The contrast parameter for the red curve @param g:float|... The contrast parameter for the green curve, defaults to `r` if `...` @param b:float|... The contrast parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves for (curve, level) in curves(r, g, b): + # But not for the curves with neutral adjustment if not level == 1.0: - for i in range(i_size): - curve[i] = (curve[i] - 0.5) * level + 0.5 + curve[:] = [(y - 0.5) * level + 0.5 for y in curve] def cie_contrast(r, g = ..., b = ...): ''' Apply contrast correction on the colour curves using CIE xyY + In this context, contrast is a measure of difference between the whitepoint and blackpoint, + if the difference is 0 than they are both grey + @param r:float The contrast parameter for the red curve @param g:float|... The contrast parameter for the green curve, defaults to `r` if `...` @param b:float|... The contrast parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Check if we can reduce the overhead, we can if the adjustments are identical same = r == g == b - if any([not level == 1.0 for level in (r, g, b)]): + # Check we need to do any adjustment + if (not same) or (not r == 1.0): if same: + # Manipulate all curves in one step if their adjustments are identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate illumination and convert back to sRGB (r_curve[i], g_curve[i], b_curve[i]) = ciexyy_to_srgb(x, y, (Y - 0.5) * r + 0.5) else: + # Manipulate all curves individually if their adjustments are not identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate illumination and convert back to sRGB (r_curve[i], _g, _b) = ciexyy_to_srgb(x, y, (Y - 0.5) * r + 0.5) (_r, g_curve[i], _b) = ciexyy_to_srgb(x, y, (Y - 0.5) * g + 0.5) (_r, _g, b_curve[i]) = ciexyy_to_srgb(x, y, (Y - 0.5) * b + 0.5) @@ -129,37 +152,51 @@ def rgb_brightness(r, g = ..., b = ...): ''' Apply brightness correction on the colour curves using sRGB + In this context, brightness is a measure of the whiteness of the whitepoint + @param r:float The brightness parameter for the red curve @param g:float|... The brightness parameter for the green curve, defaults to `r` if `...` @param b:float|... The brightness parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = r + # Maniumate the colour curves for (curve, level) in curves(r, g, b): + # But not if the adjustment is neutral if not level == 1.0: - for i in range(i_size): - curve[i] *= level + curve[:] = [y * level for y in curve] def cie_brightness(r, g = ..., b = ...): ''' Apply brightness correction on the colour curves using CIE xyY + In this context, brightness is a measure of the whiteness of the whitepoint + @param r:float The brightness parameter for the red curve @param g:float|... The brightness parameter for the green curve, defaults to `r` if `...` @param b:float|... The brightness parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Check if we can reduce the overhead, we can if the adjustments are identical same = r == g == b - if any([not level == 1.0 for level in (r, g, b)]): + # Check we need to do any adjustment + if (not same) or (not r == 1.0): if same: + # Manipulate all curves in one step if their adjustments are identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) (r_curve[i], g_curve[i], b_curve[i]) = ciexyy_to_srgb(x, y, Y * r) else: + # Manipulate all curves individually if their adjustments are not identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate illumination and convert back to sRGB (r_curve[i], _g, _b) = ciexyy_to_srgb(x, y, Y * r) (_r, g_curve[i], _b) = ciexyy_to_srgb(x, y, Y * g) (_r, _g, b_curve[i]) = ciexyy_to_srgb(x, y, Y * b) @@ -173,11 +210,16 @@ def linearise(r = True, g = ..., b = ...): @param g:bool|... Whether to convert the green colour curve, defaults to `r` if `...` @param b:bool|... Whether to convert the blue colour curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Convert colour space for i in range(i_size): + # Get values in sRGB sr, sg, sb = r_curve[i], g_curve[i], b_curve[i] + # Get values in linear RGB (lr, lg, lb) = standard_to_linear(sr, sg, sb) + # Convert selected components r_curve[i], g_curve[i], b_curve[i] = (lr if r else sr), (lg if g else sg), (lb if b else sb) @@ -189,11 +231,16 @@ def standardise(r = True, g = ..., b = ...): @param g:bool|... Whether to convert the green colour curve, defaults to `r` if `...` @param b:bool|... Whether to convert the blue colour curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Convert colour space for i in range(i_size): + # Get values in linear RGB lr, lg, lb = r_curve[i], g_curve[i], b_curve[i] + # Get values in sRGB (sr, sg, sb) = linear_to_standard(lr, lg, lb) + # Convert selected components r_curve[i], g_curve[i], b_curve[i] = (sr if r else lr), (sg if g else lg), (sb if b else lb) @@ -205,12 +252,14 @@ def gamma(r, g = ..., b = ...): @param g:float|... The gamma parameter for the green curve, defaults to `r` if `...` @param b:float|... The gamma parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves for (curve, level) in curves(r, g, b): + # But not if the adjustment is neutral if not level == 1.0: - for i in range(i_size): - curve[i] **= 1 / level + curve[:] = [y ** (1 / level) for y in curve] def negative(r = True, g = ..., b = ...): @@ -221,13 +270,14 @@ def negative(r = True, g = ..., b = ...): @param g:bool|... Whether to invert the green curve, defaults to `r` if `...` @param b:bool|... Whether to invert the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves for (curve, setting) in curves(r, g, b): + # But not if the adjustment is neutral if setting: - for i in range(i_size // 2): - j = i_size - 1 - i - curve[i], curve[j] = curve[j], curve[i] + curve[:] = reversed(curve) def rgb_invert(r = True, g = ..., b = ...): @@ -238,12 +288,14 @@ def rgb_invert(r = True, g = ..., b = ...): @param g:bool|... Whether to invert the green curve, defaults to `r` if `...` @param b:bool|... Whether to invert the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves for (curve, setting) in curves(r, g, b): + # But not if the adjustment is neutral if setting: - for i in range(i_size): - curve[i] = 1 - curve[i] + curve[:] = [1 - y for y in curve] def cie_invert(r = True, g = ..., b = ...): @@ -254,12 +306,17 @@ def cie_invert(r = True, g = ..., b = ...): @param g:bool|... Whether to invert the green curve, defaults to `r` if `...` @param b:bool|... Whether to invert the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves if any curve should be manipulated if r or g or b: for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Invert illumination and convert to back sRGB (r_, g_, b_) = ciexyy_to_srgb(x, y, 1 - Y) + # Apply the new values on the selected channels if r: r_curve[i] = r_ if g: g_curve[i] = g_ if b: b_curve[i] = b_ @@ -279,15 +336,21 @@ def sigmoid(r, g = ..., b = ...): @param g:float|...? The sigmoid parameter for the green curve, defaults to `r` if `...` @param b:float|...? The sigmoid parameter for the blue curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate the colour curves for (curve, level) in curves(r, g, b): + # But only on selected channels if level is not None: for i in range(i_size): try: curve[i] = 0.5 - math.log(1 / curve[i] - 1) / level except: - curve[i] = curve[i]; + # Corner cases: + # curve[i] = 0 → 0 -- Division by zero + # curve[i] = 1 → 1 -- Logarithm of zero + pass def rgb_limits(r_min, r_max, g_min = ..., g_max = ..., b_min = ..., b_max = ...): @@ -301,14 +364,16 @@ def rgb_limits(r_min, r_max, g_min = ..., g_max = ..., b_min = ..., b_max = ...) @param b_min:float|... The blue component value of the black point, defaults to `g_min` @param b_max:float|... The blue component value of the white point, defaults to `g_max` ''' + # Handle overloading if g_min is ...: g_min = r_min if g_max is ...: g_max = r_max if b_min is ...: b_min = g_min if b_max is ...: b_max = g_max + # Manipulate the colour curves for (curve, (level_min, level_max)) in curves((r_min, r_max), (g_min, g_max), (b_min, b_max)): + # But not if the adjustments are neutral if (level_min != 0) or (level_max != 1): - for i in range(i_size): - curve[i] = curve[i] * (level_max - level_min) + level_min + curve[:] = [y * (level_max - level_min) + level_min for y in curve] def cie_limits(r_min, r_max, g_min = ..., g_max = ..., b_min = ..., b_max = ...): @@ -322,26 +387,33 @@ def cie_limits(r_min, r_max, g_min = ..., g_max = ..., b_min = ..., b_max = ...) @param b_min:float|... The blue component value of the black point, defaults to `g_min` @param b_max:float|... The blue component value of the white point, defaults to `g_max` ''' + # Handle overloading if g_min is ...: g_min = r_min if g_max is ...: g_max = r_max if b_min is ...: b_min = g_min if b_max is ...: b_max = g_max + # Check if we can reduce the overhead, we can if the adjustments are identical same = (r_min == g_min == b_min) and (r_max == g_max == b_max) - if any([lvl != 0 for lvl in (r_min, g_min, b_min)]) or any([lvl != 1 for lvl in (r_max, g_max, b_max)]): + # Check we need to do any adjustment + if (not same) or (not r_min == 0) or (not r_max == 0): if same: + # Manipulate all curves in one step if their adjustments are identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate illumination Y = Y * (r_max - r_min) + r_min + # Convert back to sRGB (r_curve[i], g_curve[i], b_curve[i]) = ciexyy_to_srgb(x, y, Y) else: + # Manipulate all curves individually if their adjustments are not identical for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) - rY = Y * (r_max - r_min) + r_min - gY = Y * (g_max - g_min) + g_min - bY = Y * (b_max - b_min) + b_min - (r_curve[i], _g, _b) = ciexyy_to_srgb(x, y, rY) - (_r, g_curve[i], _b) = ciexyy_to_srgb(x, y, gY) - (_r, _g, b_curve[i]) = ciexyy_to_srgb(x, y, bY) + # Manipulate illumination and convert back to sRGB + (r_curve[i], _g, _b) = ciexyy_to_srgb(x, y, Y * (r_max - r_min) + r_min) + (_r, g_curve[i], _b) = ciexyy_to_srgb(x, y, Y * (g_max - g_min) + g_min) + (_r, _g, b_curve[i]) = ciexyy_to_srgb(x, y, Y * (b_max - b_min) + b_min) def manipulate(r, g = ..., b = ...): @@ -358,12 +430,14 @@ def manipulate(r, g = ..., b = ...): For example, if the red value 0.5 is already mapped to 0.25, then if the function maps 0.25 to 0.5, the red value 0.5 will revert back to being mapped to 0.5. ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulate colour curves for (curve, f) in curves(r, g, b): + # But only for selected channels if f is not None: - for i in range(i_size): - curve[i] = f(curve[i]) + curve[:] = [f(y) for y in curve] def cie_manipulate(r, g = ..., b = ...): @@ -380,17 +454,27 @@ def cie_manipulate(r, g = ..., b = ...): For example, if the value 0.5 is already mapped to 0.25, then if the function maps 0.25 to 0.5, the value 0.5 will revert back to being mapped to 0.5. ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Check if we can reduce the overhead, we can if the adjustments are identical same = (r is g) and (g is b) if same: + # Manipulate all curves in one step if their adjustments are identical if r is not None: + # But not if the we are not given a function for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate and convert by to sRGB (r_curve[i], g_curve[i], b_curve[i]) = ciexyy_to_srgb(x, y, r(Y)) elif any(f is not None for f in (r, g, b)): + # Manipulate all curves individually if their adjustments are not identical + # if we are given a function for any curve for i in range(i_size): + # Convert to CIE xyY (x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i]) + # Manipulate and convert by to sRGB for selected channels individually if r is not None: (r_curve[i], _g, _b) = ciexyy_to_srgb(x, y, r(Y)) if g is not None: (_r, g_curve[i], _b) = ciexyy_to_srgb(x, y, g(Y)) if b is not None: (_r, _g, b_curve[i]) = ciexyy_to_srgb(x, y, b(Y)) @@ -410,27 +494,34 @@ def lower_resolution(rx_colours = None, ry_colours = None, gx_colours = ..., gy_ Where `None` is used the default value will be used, for *x_colours:es that is `i_size`, and for *y_colours:es that is `o_size` ''' + # Handle overloading if gx_colours is ...: gx_colours = rx_colours if gy_colours is ...: gy_colours = ry_colours if bx_colours is ...: bx_colours = gx_colours if by_colours is ...: by_colours = gy_colours + # Select default values where default is requested if rx_colours is None: rx_colours = i_size if ry_colours is None: ry_colours = o_size if gx_colours is None: gx_colours = i_size if gy_colours is None: gy_colours = o_size if bx_colours is None: bx_colours = i_size if by_colours is None: by_colours = o_size + # Combine pair X and Y parameters for each channel r_colours = (rx_colours, ry_colours) g_colours = (gx_colours, gy_colours) b_colours = (bx_colours, by_colours) + # Manipulate colour curves for i_curve, (x_colours, y_colours) in curves(r_colours, g_colours, b_colours): + # But not if adjustment is neutral if (x_colours == i_size) and (y_colours == o_size): continue o_curve = [0] * i_size x_, y_, i_ = x_colours - 1, y_colours - 1, i_size - 1 for i in range(i_size): + # Scale encoding x = int(i * x_colours / i_size) x = int(x * i_ / x_) + # Scale output y = int(i_curve[x] * y_ + 0.5) o_curve[i] = y / y_ i_curve[:] = o_curve @@ -444,11 +535,9 @@ def start_over(): calibrated the monitors or you have awesome monitors that support hardware gamma correction. ''' + # Reset colour curves for i in range(i_size): - v = i / (i_size - 1) - r_curve[i] = v - g_curve[i] = v - b_curve[i] = v + r_curve[i] = g_curve[i] = b_curve[i] = i / (i_size - 1) def clip(r = True, g = ..., b = ...): @@ -459,10 +548,12 @@ def clip(r = True, g = ..., b = ...): @param g:bool|... Whether to clip the green colour curve, defaults to `r` if `...` @param b:bool|... Whether to clip the blue colour curve, defaults to `g` if `...` ''' + # Handle overloading if g is ...: g = r if b is ...: b = g + # Manipulation colour curves for curve, action in curves(r, g, b): + # But only for selected channels if action: - for i in range(i_size): - curve[i] = min(max(0.0, curve[i]), 1.0) + curve[:] = [min(max(0.0, y), 1.0) for y in curve] |