From 81a86b2b043401f7d036364e9aedf9d7b584e34b Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Wed, 13 Jan 2016 06:53:23 -0700
Subject: [PATCH] applets/plot_xy_hist: do not clear arrow/histogram when
 unrelated data is modified

---
 artiq/applets/plot_xy_hist.py | 64 +++++++++++++++++++++++++++++------
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/artiq/applets/plot_xy_hist.py b/artiq/applets/plot_xy_hist.py
index b74dd724d..8f31615e1 100755
--- a/artiq/applets/plot_xy_hist.py
+++ b/artiq/applets/plot_xy_hist.py
@@ -6,6 +6,17 @@ import pyqtgraph
 from artiq.applets.simple import SimpleApplet
 
 
+def _compute_ys(histogram_bins, histograms_counts):
+        bin_centers = np.empty(len(histogram_bins)-1)
+        for i in range(len(bin_centers)):
+            bin_centers[i] = (histogram_bins[i] + histogram_bins[i+1])/2
+
+        ys = np.empty(histograms_counts.shape[0])
+        for n, counts in enumerate(histograms_counts):
+            ys[n] = sum(bin_centers*counts)/sum(counts)
+        return ys
+
+
 class XYHistPlot(pyqtgraph.GraphicsWindow):
     def __init__(self, args):
         pyqtgraph.GraphicsWindow.__init__(self, title="XY/Histogram")
@@ -15,6 +26,7 @@ class XYHistPlot(pyqtgraph.GraphicsWindow):
         self.xy_plot = self.addPlot()
         self.xy_plot_data = None
         self.arrow = None
+        self.selected_index = None
 
         self.hist_plot = self.addPlot()
         self.hist_plot_data = None
@@ -27,28 +39,36 @@ class XYHistPlot(pyqtgraph.GraphicsWindow):
         self.xy_plot_data = None
         self.hist_plot_data = None
         self.arrow = None
+        self.selected_index = None
 
         self.histogram_bins = histogram_bins
-        bin_centers = np.empty(len(histogram_bins)-1)
-        for i in range(len(bin_centers)):
-            bin_centers[i] = (histogram_bins[i] + histogram_bins[i+1])/2
-
-        ys = np.empty_like(xs)
-        for n, counts in enumerate(histograms_counts):
-            ys[n] = sum(bin_centers*counts)/sum(counts)
 
+        ys = _compute_ys(self.histogram_bins, histograms_counts)
         self.xy_plot_data = self.xy_plot.plot(x=xs, y=ys,
                                               pen=None,
                                               symbol="x", symbolSize=20)
         self.xy_plot_data.sigPointsClicked.connect(self._point_clicked)
-        for point, counts in zip(self.xy_plot_data.scatter.points(),
-                                 histograms_counts):
+        for index, (point, counts) in (
+                enumerate(zip(self.xy_plot_data.scatter.points(),
+                              histograms_counts))):
+            point.histogram_index = index
             point.histogram_counts = counts
 
         self.hist_plot_data = self.hist_plot.plot(
             stepMode=True, fillLevel=0,
             brush=(0, 0, 255, 150))
 
+    def _set_partial_data(self, xs, histograms_counts):
+        ys = _compute_ys(self.histogram_bins, histograms_counts)
+        self.xy_plot_data.setData(x=xs, y=ys,
+                                  pen=None,
+                                  symbol="x", symbolSize=20)
+        for index, (point, counts) in (
+                enumerate(zip(self.xy_plot_data.scatter.points(),
+                              histograms_counts))):
+            point.histogram_index = index
+            point.histogram_counts = counts
+
     def _point_clicked(self, data_item, spot_items):
         spot_item = spot_items[0]
         position = spot_item.pos()
@@ -61,14 +81,38 @@ class XYHistPlot(pyqtgraph.GraphicsWindow):
             self.xy_plot.addItem(self.arrow)
         else:
             self.arrow.setPos(position)
+        self.selected_index = spot_item.histogram_index
         self.hist_plot_data.setData(x=self.histogram_bins,
                                     y=spot_item.histogram_counts)
 
+    def _can_use_partial(self, mods):
+        if self.hist_plot_data is None:
+            return False
+        for mod in mods:
+            if mod["action"] != "setitem":
+                return False
+            if mod["path"] == [self.args.xs, 1]:
+                if mod["key"] == self.selected_index:
+                    return False
+            elif mod["path"][:2] == [self.args.histograms_counts, 1]:
+                if len(mod["path"]) > 2:
+                    index = mod["path"][2]
+                else:
+                    index = mod["key"]
+                if index == self.selected_index:
+                    return False
+            else:
+                return False
+        return True
+
     def data_changed(self, data, mods):
         xs = data[self.args.xs][1]
         histogram_bins = data[self.args.histogram_bins][1]
         histograms_counts = data[self.args.histograms_counts][1]
-        self._set_full_data(xs, histogram_bins, histograms_counts)
+        if self._can_use_partial(mods):
+            self._set_partial_data(xs, histograms_counts)
+        else:
+            self._set_full_data(xs, histogram_bins, histograms_counts)
         
 
 def main():