applets: add XY/histogram plot demo

artiq/applets/plot_xy_hist.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python3.5
+
+from pyqtgraph.Qt import QtGui, QtCore
+import pyqtgraph as pg
+
+import numpy as np
+
+class XYHistPlot:
+    def __init__(self):
+        self.graphics_window = pg.GraphicsWindow(title="XY/Histogram")
+        self.graphics_window.resize(1000,600)
+        self.graphics_window.setWindowTitle("XY/Histogram")
+
+        self.xy_plot = self.graphics_window.addPlot()
+        self.xy_plot_data = None
+        self.arrow = None
+
+        self.hist_plot = self.graphics_window.addPlot()
+        self.hist_plot_data = None
+
+    def set_data(self, xs, histograms_bins, histograms_counts):
+        ys = np.empty_like(xs)
+        ys.fill(np.nan)
+        for n, (bins, counts) in enumerate(zip(histograms_bins,
+                                               histograms_counts)):
+            bin_centers = np.empty(len(bins)-1)
+            for i in range(len(bin_centers)):
+                bin_centers[i] = (bins[i] + bins[i+1])/2
+            ys[n] = sum(bin_centers*counts)/sum(bin_centers)
+
+        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, bins, counts in zip(self.xy_plot_data.scatter.points(),
+                                       histograms_bins, histograms_counts):
+            point.histogram_bins = bins
+            point.histogram_counts = counts
+
+        self.hist_plot_data = self.hist_plot.plot(
+                            stepMode=True, fillLevel=0,
+                            brush=(0, 0, 255, 150))
+
+    def point_clicked(self, data_item, spot_items):
+        spot_item = spot_items[0]
+        position = spot_item.pos()
+        if self.arrow is None:
+            self.arrow = pg.ArrowItem(angle=-120, tipAngle=30, baseAngle=20,
+                                      headLen=40, tailLen=40, tailWidth=8,
+                                      pen=None, brush="y")
+            self.arrow.setPos(position)
+            # NB: temporary glitch if addItem is done before setPos
+            self.xy_plot.addItem(self.arrow)
+        else:
+            self.arrow.setPos(position)
+        self.hist_plot_data.setData(x=spot_item.histogram_bins,
+                                    y=spot_item.histogram_counts)
+        
+
+def main():
+    app = QtGui.QApplication([])
+    plot = XYHistPlot()
+    plot.set_data(np.array([1, 2, 3, 4, 1]),
+                  np.array([[1, 2, 3], [1, 2, 3], [1, 2, 3], [40, 70, 100], [4, 7, 10, 20]]),
+                  np.array([[1, 1], [2, 3], [10, 20], [3, 1], [100, 67, 102]]))
+    app.exec_()
+
+if __name__ == '__main__':
+    main()