[ff-cvs] libvob vob/color/spaces.py vob/demo/lava/gamma....

[Tuomas J. Lukka]

CVSROOT:        /cvsroot/libvob
Module name:    libvob
Branch:         
Changes by:     Tuomas J. Lukka <address@hidden>        03/09/23 06:38:32

Modified files:
        vob/color      : spaces.py 
        vob/demo/lava  : gamma.py 
Added files:
        doc/pegboard/glmosaictext_java--tjl: peg.rst 

Log message:
        Arch sync

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/libvob/libvob/doc/pegboard/glmosaictext_java--tjl/peg.rst?rev=1.1
http://savannah.gnu.org/cgi-bin/viewcvs/libvob/libvob/vob/color/spaces.py.diff?tr1=1.5&tr2=1.6&r1=text&r2=text
http://savannah.gnu.org/cgi-bin/viewcvs/libvob/libvob/vob/demo/lava/gamma.py.diff?tr1=1.1&tr2=1.2&r1=text&r2=text

Patches:
Index: libvob/vob/color/spaces.py
diff -u libvob/vob/color/spaces.py:1.5 libvob/vob/color/spaces.py:1.6
--- libvob/vob/color/spaces.py:1.5      Mon Sep 22 04:49:01 2003
+++ libvob/vob/color/spaces.py  Tue Sep 23 06:38:32 2003
@@ -37,32 +37,48 @@
 G = .30,.60
 B = .15,.06
 
-# coordinates of the white point (i.e., R = G = B = 1) --
+# Chromaiticy coordinates of the white point (i.e., R = G = B = 1) --
 # this determines the relative luminances of the primaries
 # W = .312713,.329016 # = D65 standard illuminant
 W = .3127268660,.3290235126 # = D65 standard illuminant [CIE 15.2, p.55]
 
-# The gamma used for converting linear RGB to monitor RGB
-gamma = 2.2
+# The gamma and offset used for converting linear RGB to monitor RGB
+gamma = 2.4 # sRGB standard
+offset = .055 
 
 # The uncorrected display gamma of PC's is typically 2.2, i.e.,
 # RGB values map to physical intensities with an exponent of 2.2.
-# So, gamma correction of 2.2 here should result in linear intensity.
-
-# These may later be changed to use the sRGB standard
-# (which is almost the same as the simple 2.2 gamma).
+# So, gamma correction of 2.2 (or 2.4 with .055 offset)
+# here should result in linear intensity.
 
 def linear_to_monitor(rgb):
     def f(x):
         if x < 0: return -f(-x)
-        return x**(1.0/gamma)
+        if offset == 0: return x**(1.0/gamma)
+
+        # Use a linear segment near zero
+        t = offset / (gamma - 1)
+        t2 = (t * gamma / (1 + offset))**gamma
+        c = t / (t * gamma / (1 + offset))**gamma
+        if x < t2:
+            return x * c
+        
+        return x**(1.0/gamma) * (1 + offset) - offset
+
     return (f(rgb[0]), f(rgb[1]), f(rgb[2]))
 
 def monitor_to_linear(rgb):
     def f(x):
         if x < 0: return -f(-x)
-        return x**gamma
-
+        if offset == 0: return x**gamma
+        
+        # Use a linear segment near zero
+        t = offset / (gamma - 1)
+        c = t / (t * gamma / (1 + offset))**gamma 
+        if x < t:
+            return x / c
+        
+        return ((x + offset) / (1 + offset))**gamma
     
     return (f(rgb[0]), f(rgb[1]), f(rgb[2]))
 
@@ -272,16 +288,19 @@
 # a luminance component and a color plane vector whose angle and
 # radius specify the hue and saturation, respectively.
 #
-# The Y component is the CIE Y luminance (but the weights can be changed) and
-# the ST-plane has the RGB primaries 120 (R = 0, G = 120, B = 240) degrees 
apart
-# at radius 1.
+# The Y component is the CIE Y luminance and
+# the ST-plane has the RGB primaries 120 (R = 0, G = 120, B = 240)
+# degrees apart at radius 1.
 #    
-# Luminance weights of the RGB primaries used in YST color space functions
+# Luminance weights of the RGB primaries used in YST color space
+# functions:
 #Wr = 0.212671 
 #Wg = 0.715160
 #Wb = 0.072169
-#Note: the weigths are computed from the values specified at the beginning
-#of this file
+# Note: the weigths are computed from the values specified at the
+#       beginning of this file
+# Note: the YST color space is device dependent unless
+#       a standardized RGB space is used
 
 def YSTtoRGB(v):
     mat =  [ [1, Wg+Wb,    (Wb - Wg) / math.sqrt(3) ],
Index: libvob/vob/demo/lava/gamma.py
diff -u libvob/vob/demo/lava/gamma.py:1.1 libvob/vob/demo/lava/gamma.py:1.2
--- libvob/vob/demo/lava/gamma.py:1.1   Mon Sep 22 04:49:01 2003
+++ libvob/vob/demo/lava/gamma.py       Tue Sep 23 06:38:32 2003
@@ -36,7 +36,8 @@
     def __init__(self):
        self.key = KeyPresses(
             self, 
-           SlideLin("gamma", 2.2, .05, "exponent", "Down", "Up"),
+           SlideLin("gamma", 2.4, .05, "exponent", "Down", "Up"),
+           SlideLin("offset", .055, .005, "offset", "Left", "Right"),
             )
 
         code = """
@@ -70,6 +71,22 @@
         self.stripe2 = getDList(code)
 
         code = """
+        LineWidth 1.0
+        Begin LINES
+        """
+        for i in range(0,N):
+            if i % 3 != 1:
+                code += """
+                Vertex .6666 %s
+                Vertex 1 %s
+                """ % (i, i)
+                
+        code += """
+        End
+        """
+        self.stripe3 = getDList(code)
+
+        code = """
         Begin QUAD_STRIP
         Vertex .3333 0
         Vertex .6666 0
@@ -81,6 +98,7 @@
 
     def scene(self, vs):
         vob.color.spaces.gamma = self.gamma
+        vob.color.spaces.offset = self.offset
         
         vs.put( background( (0, 0, 0) ) )
         
@@ -88,17 +106,30 @@
         i = 0
         for cs in css:
             col = [(1,1,1),(0,1,0),(1,0,0),(0,0,1)][i&3]
-            f = (1 - (i / 4) * .2)**3
+            f = .5 * (1 - (i / 4) * .2)**3
             i += 1
             col = [c * f for c in col]
-            col1 = [c * 1.5 for c in col]
-            col2 = [c * .5 for c in col]
-            vs.put(color(col))
-            vs.map.put(self.stripe, cs)
+            col1 = [c * 2 for c in col]
+            col2 = [c * 3 for c in col]
+            col3 = [c * 3 / 2 for c in col]
+
             if (col1[0] <= 1.0001 and
                 col1[1] <= 1.0001 and
                 col1[2] <= 1.0001):
                 vs.put(color(col1))
+                vs.map.put(self.stripe, cs)
+
+            if (col2[0] <= 1.0001 and
+                col2[1] <= 1.0001 and
+                col2[2] <= 1.0001):
+                vs.put(color(col2))
                 vs.map.put(self.stripe2, cs)
-            vs.put(color(col2))
+            elif (col3[0] <= 1.0001 and
+                  col3[1] <= 1.0001 and
+                  col3[2] <= 1.0001):
+                vs.put(color(col3))
+                vs.map.put(self.stripe3, cs)
+
+            vs.put(color(col))
             vs.map.put(self.block, cs)
+