--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/views/plots.py	Wed Nov 05 15:52:50 2008 +0100
@@ -0,0 +1,103 @@
+import os
+
+from logilab.common import flatten
+
+from cubicweb.web.views import baseviews
+
+def plot_selector(cls, req, rset, *args, **kwargs):
+    """accept result set with at least one line and two columns of result
+    all columns after second must be of numerical types"""
+    if rset is None:
+        return 0
+    if not len(rset):
+        return 0
+    if len(rset.rows[0]) < 2:
+        return 0
+    for etype in rset.description[0]:
+        if etype not in ('Int', 'Float'):
+            return 0
+    return 1
+
+try:
+    import matplotlib
+    import sys
+    if 'matplotlib.backends' not in sys.modules:
+        matplotlib.use('Agg')
+    from matplotlib.ticker import FormatStrFormatter
+    from pylab import figure, show
+except ImportError:
+    pass
+else:
+    class PlotView(baseviews.AnyRsetView):
+        id = 'plot'
+        title = _('generic plot')
+        binary = True
+        content_type = 'image/png'
+        _plot_count = 0
+        __selectors__ = (plot_selector,)
+
+        def call(self, width=None, height=None):
+            # compute dimensions
+            if width is None:
+                if 'width' in self.req.form:
+                    width = int(self.req.form['width'])
+                else:
+                    width = 500
+
+            if height is None:
+                if 'height' in self.req.form:
+                    height = int(self.req.form['height'])
+                else:
+                    height = 400
+            dpi = 100.
+
+            # compute data
+            abscisses = [row[0] for row in self.rset]
+            courbes = []
+            nbcols = len(self.rset.rows[0])
+            for col in range(1,nbcols):
+                courbe = [row[col] for row in self.rset]
+                courbes.append(courbe)
+            if not courbes:
+                raise Exception('no data')
+            # plot data
+            fig = figure(figsize=(width/dpi, height/dpi), dpi=dpi)
+            ax = fig.add_subplot(111)
+            colors = 'brgybrgy'
+            try:
+                float(abscisses[0])
+                xlabels = None
+            except ValueError:
+                xlabels = abscisses
+                abscisses = range(len(xlabels))
+            for idx,courbe in enumerate(courbes):
+                ax.plot(abscisses, courbe, '%sv-' % colors[idx], label=self.rset.description[0][idx+1])
+            ax.autoscale_view()
+            alldata = flatten(courbes)
+            m, M = min(alldata or [0]), max(alldata or [1])
+            if m is None: m = 0
+            if M is None: M = 0
+            margin = float(M-m)/10
+            ax.set_ylim(m-margin, M+margin)
+            ax.grid(True)
+            ax.legend(loc='best')
+            if xlabels is not None:
+                ax.set_xticks(abscisses)
+                ax.set_xticklabels(xlabels)
+            try:
+                fig.autofmt_xdate()
+            except AttributeError:
+                # XXX too old version of matplotlib. Ignore safely.
+                pass
+
+            # save plot
+            filename = self.build_figname()
+            fig.savefig(filename, dpi=100)
+            img = open(filename, 'rb')
+            self.w(img.read())
+            img.close()
+            os.remove(filename)
+
+        def build_figname(self):
+            self.__class__._plot_count += 1
+            return '/tmp/burndown_chart_%s_%d.png' % (self.config.appid, self.__class__._plot_count)