Merge pull request #528 from somospocos/braille-graph

[core/output] add support for drawing graphs using Braille chars

bumblebee/output.py

@@ -30,6 +30,33 @@ VBARS = [
     u"\u258a",
     u"\u2589",
     u"\u2588"]
+BRAILLE = {
+    (0, 0): u" ",
+    (1, 0): u"\u2840",
+    (2, 0): u"\u2844",
+    (3, 0): u"\u2846",
+    (4, 0): u"\u2847",
+    (0, 1): u"\u2880",
+    (0, 2): u"\u28a0",
+    (0, 3): u"\u28b0",
+    (0, 4): u"\u28b8",
+    (1, 1): u"\u28c0",
+    (2, 1): u"\u28c4",
+    (3, 1): u"\u28c6",
+    (4, 1): u"\u28c7",
+    (1, 2): u"\u28e0",
+    (2, 2): u"\u28e4",
+    (3, 2): u"\u28e6",
+    (4, 2): u"\u28e7",
+    (1, 3): u"\u28f0",
+    (2, 3): u"\u28f4",
+    (3, 3): u"\u28f6",
+    (4, 3): u"\u28f7",
+    (1, 4): u"\u28f8",
+    (2, 4): u"\u28fc",
+    (3, 4): u"\u28fe",
+    (4, 4): u"\u28ff"
+}
 
 log = logging.getLogger(__name__)
 
@@ -169,6 +196,80 @@ def vbar(value, width):
     return VBar(value, width).get_chars()
 
 
+class BrailleGraph(object):
+    """
+        graph using Braille chars
+        scaled to passed values
+    """
+    def __init__(self, values):
+        """
+            Args:
+
+                values (list): list of values
+        """
+        self.values = values
+        # length of values list must be even
+        # because one Braille char displays two values
+        if len(self.values) % 2 == 1:
+            self.values.append(0)
+        self.steps = self.get_steps()
+        self.parts = [tuple(self.steps[i:i+2])
+                      for i in range(len(self.steps))[::2]]
+
+    @staticmethod
+    def get_height(value, unit):
+        """
+            Compute height of a value relative to unit
+
+            Args:
+
+                value (number): value
+
+                unit (number): unit
+        """
+        if value < unit / 10.:
+            return 0
+        elif value <= unit:
+            return 1
+        elif value <= unit * 2:
+            return 2
+        elif value <= unit * 3:
+            return 3
+        else:
+            return 4
+
+    def get_steps(self):
+        """
+            Convert the list of values to a list of steps
+
+            Return: list
+        """
+        maxval = max(self.values)
+        unit = maxval / 4.
+        if unit == 0:
+            return [0] * len(self.values)
+        stepslist = []
+        for value in self.values:
+            stepslist.append(self.get_height(value, unit))
+        return stepslist
+
+    def get_chars(self):
+        """
+            Decide which chars to draw
+
+            Return: str
+        """
+        chars = []
+        for part in self.parts:
+            chars.append(BRAILLE[part])
+        return "".join(chars)
+
+
+def bgraph(values):
+    """wrapper function"""
+    return BrailleGraph(values).get_chars()
+
+
 class Widget(bumblebee.store.Store):
     """Represents a single visible block in the status bar"""
     def __init__(self, full_text="", name=""):