Added PNG charts.

1 files changed, 53 insertions, 0 deletions

diff --git a/pngchart.py b/pngchart.py
new file mode 100644
index 0000000..5428718
--- /dev/null
+++ b/pngchart.py
@@ -0,0 +1,53 @@
+from pngcanvas import PNGCanvas
+
+try:
+    from itertools import izip as zip
+except ImportError:
+    pass
+
+class SimpleLineChart(object):
+    def __init__(self, width, height, colours=None, legend=None):
+        self.canvas = PNGCanvas(width, height)
+
+        self.width = width
+        self.height = height
+
+        self.colours = colours
+        self.legend = legend
+
+        self.series = []
+
+    def add_data(self, series):
+        self.series.append(series)
+
+    def render(self):
+        max_width = max(map(len, self.series))
+        max_height = max(map(max, self.series))
+        x_scale = float(self.width) / max_width
+        y_scale = float(self.height) / max_height
+
+        data = zip(self.series, self.colours or [], self.legend or [])
+        for series, colour, legend in data:
+            colour = int(colour, 16)
+            self.canvas.color = (
+                colour>>16 & 0xff,
+                colour>>8 & 0xff,
+                colour & 0xff,
+                0xff,
+            )
+            last = None
+            for x, y in enumerate(series):
+                if y is not None:
+                    y = self.height - y * y_scale
+                    if last is not None:
+                        x *= x_scale
+                        self.canvas.line(x - x_scale, last, x, y)
+                last = y
+
+    def download(self, filename):
+        self.render()
+
+        f = open(filename, 'wb')
+        f.write(self.canvas.dump())
+        f.close()
+