initial commit

apollon-master/coloring.py

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+# Select a color from colorbrewer schemes
+
+# Copyright (c) 2014 Ludger Sandig
+# This file is part of apollon.
+
+# Apollon is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# Apollon is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with Apollon.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import json
+
+class ColorMap(object):
+    """
+    Map numbers to colors.
+    """
+    def __init__(self, default):
+        """
+        @param default: Is returned when a number can't be mapped.
+        """
+        self.pairs = []
+        self.default = default
+
+    def add_interval(self, left, right, color):
+        """
+        A number in interval [left,right] gets mapped to color.
+        """
+        self.pairs.append((left, right, color))
+
+    def color_for(self, number):
+        """
+        Map number to color. If not found, return default value.
+        """
+        ret = self.default
+        for p in self.pairs:
+            if (number >= p[0]) and (number <= p[1]):
+                ret = p[2]
+                break
+        return ret
+
+class ColorScheme(object):
+    """
+    Color Scheme helper class.
+    """
+    def __init__(self, filename):
+        """
+        Load color scheme definitions from json file.
+        """
+        json_data = open(filename)
+
+        self.schemes=json.load(json_data)
+        json_data.close()
+
+    def info(self):
+        """
+        Get information on available color schemes
+        """
+        infos = []
+        for name in self.schemes:
+            smallest = min(self.schemes[name], key=lambda k: len(self.schemes[name][k]))
+            biggest = max(self.schemes[name], key=lambda k: len(self.schemes[name][k]))
+            infos.append({"name" : name, "low" : int(smallest), "high" : int(biggest)})
+        return infos
+
+    def makeMap(self, frm, to, name, res):
+        """
+        Construct a L{ColorMap} that maps numbers between frm and to to color scheme name with resolution res.
+        """
+        # TODO: Proper error handling when name or res are not available
+        delta = to-frm
+        step = delta/res
+        colors = self.schemes[name][str(res)]
+        mp = ColorMap("none")
+        # Items are (lower_bound, color)
+        for n in range(res):
+            mp.add_interval(frm + n*step, frm + (n+1)*step, colors[n])
+        return mp