add cie_manipulate

Signed-off-by: Mattias Andrée <maandree@operamail.com>

3 files changed, 26 insertions, 0 deletions

diff --git a/examples/lisp-esque.conf b/examples/lisp-esque.conf
index 8e1e383..dbf7a68 100644
--- a/examples/lisp-esque.conf
+++ b/examples/lisp-esque.conf
@@ -325,5 +325,10 @@
 	;                          nil ; Do nothing on the second monitor
 	;              )
 	;     (standardise yes no)
+	; You can also use (manipulate) on the Y component of the CIE xyY
+	; colour space:
+	;    (manipulate:cie 'lambda x : math.log(x + 1, 2)'
+	;                    nil ; Do nothing on the second monitor
+	;    )
 )
 
diff --git a/info/blueshift.texinfo b/info/blueshift.texinfo
index 7b2c3fc..44cdea7 100644
--- a/info/blueshift.texinfo
+++ b/info/blueshift.texinfo
@@ -542,6 +542,11 @@ Applies the functions @code{r}, @code{g} and
 @code{b} : float @click{} float to red, green
 and blue colour curves, respectively.
 
+@item cie_manipulate(f)
+Applies the function @code{f} : float @click{}
+float to Y component (illumination) colour curves
+converted to CIE xyY.
+
 @item temperature(temperature, algorithm)
 Applies the a blackbody colour temperature of
 @code{temperature}@footnote{Actually multiplied
diff --git a/src/curve.py b/src/curve.py
index 4ef52a4..cac2b53 100644
--- a/src/curve.py
+++ b/src/curve.py
@@ -473,6 +473,22 @@ def manipulate(r, g = None, b = None):
             curve[i] = f(curve[i])
 
 
+def cie_manipulate(f):
+    '''
+    Manipulate the colour curves using a lambda function on the CIE xyY colour space
+    
+    @param  f:(float)?→float   Lambda function to manipulate the Y component, nothing is done if `f` is `None`
+    
+    The lambda functions thats a colour value and maps it to a new illumination value.
+    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.
+    '''
+    if f is not None:
+        for i in range(i_size):
+            (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, f(Y))
+
+
 def lower_resolution(rx_colours = None, ry_colours = None, gx_colours = None, gy_colours = None, bx_colours = None, by_colours = None):
     '''
     Emulates low colour resolution