swatch: Create a colour swatch from a traversal of the RGB colour cube.

scurve/draw.py

@@ -131,3 +131,32 @@ class Curve:
     def save(self, fname):
         self.c.save(fname)
 
+
+
+class Swatch:
+    def __init__(self, curve, colorwidth, height):
+        """
+            Color swatches from the RGB color cube.
+
+            curve: A curve with dimension 3.
+            colorwidth: Width of an individual color. Image width will be
+            len(curve)*colorwidth.
+            height: Height of the image
+        """
+        self.curve, self.colorwidth, self.height = curve, colorwidth, height
+        self.c = Canvas(len(self.curve) * colorwidth, self.height)
+        self.ctx = self.c.ctx()
+        self.ctx.set_antialias(False)
+
+    def save(self, fname):
+        d = float(self.curve.dimensions()[0])
+        offset = 0
+        for r, g, b in self.curve:
+            self.ctx.set_source_rgb(
+                r/d, g/d, b/d
+            )
+            self.ctx.rectangle(offset, 0, self.colorwidth, self.height)
+            self.ctx.fill()
+            offset += self.colorwidth
+        self.c.save(fname)
+

scurve/hilbert.py

@@ -87,8 +87,8 @@ class Hilbert:
             Size is the total number of points in the curve.
         """
         x = math.log(size, 2)
-        if not x == int(x):
-            raise ValueError("Size does not fit a square Hilbert curve.")
+        if not float(x)/dimension == int(x)/dimension:
+            raise ValueError("Size does not fit Hilbert curve of dimension %s."%dimension)
         return Hilbert(dimension, int(x/dimension))
 
     def __len__(self):

swatch

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+import os.path, math
+import scurve
+from scurve import draw
+
+def main():
+    from optparse import OptionParser, OptionGroup
+    parser = OptionParser(
+                usage = "%prog [options] output",
+                version="%prog 0.1",
+            )
+    parser.add_option(
+        "-s", "--height", action="store",
+        type = "int", dest="height", default=50,
+        help = "Height of the swatch."
+    )
+    parser.add_option(
+        "-w", "--colorwidth", action="store",
+        type = "int", dest="colorwidth", default=10,
+        help = "Width of each color."
+    )
+    parser.add_option(
+        "-p", "--points", action="store",
+        type="int", dest="points", default=64,
+        help = "Total number of points on the curve."
+    )
+    parser.add_option(
+        "-c", "--curve", action="store",
+        type="str", dest="curve", default="hilbert"
+    )
+    options, args = parser.parse_args()
+    if len(args) != 1:
+        parser.error("Please specify output file.")
+
+    c = scurve.fromSize(options.curve, 3, options.points)
+
+    d = draw.Swatch(c, options.colorwidth, options.height)
+    d.save(args[0])
+
+
+main()