enh: export event image via context menu in Quick View (close #35)

Author: paulmueller

CHANGELOG

@@ -1,3 +1,5 @@
+2.0.4
+ - enh: export event image via context menu in Quick View (#35)
 2.0.3
  - setup: bump dclab from 0.20.3 to 0.21.1
  - docs: add terminology section (#12)

shapeout2/gui/widgets/simple_image_view.py

@@ -1,3 +1,5 @@
+import numpy as np
+from PyQt5 import QtCore, QtGui, QtWidgets
 import pyqtgraph as pg
 
 from .simple_plot_widget import SimpleViewBox
@@ -9,6 +11,8 @@ class SimpleImageView(pg.ImageView):
     def __init__(self, *args, **kwargs):
         super(SimpleImageView, self).__init__(view=SimpleImageViewBox(),
                                               *args, **kwargs)
+        self.view.export.connect(self.on_export)
+
         # disable pyqtgraph controls we don't need
         self.ui.histogram.hide()
         self.ui.roiBtn.hide()
@@ -17,8 +21,31 @@ def __init__(self, *args, **kwargs):
         self.keyPressEvent = lambda _: None
         self.keyReleaseEvent = lambda _: None
 
+    def on_export(self, suffix):
+        assert suffix == "png"
+        path, _ = QtWidgets.QFileDialog.getSaveFileName(
+            self, '', '', 'PNG image (*.png)', '')
+        if not path.endswith(".png"):
+            path += ".png"
+        vmin, vmax = self.getLevels()
+        arr = (self.image - vmin) / (vmax-vmin) * 255
+        img = np.require(arr, np.uint8, 'C')
+        height, width, _ = self.image.shape
+
+        qImg = QtGui.QImage(img, width, height, width *
+                            3, QtGui.QImage.Format_RGB888)
+        qImg.save(path)
+
 
 class SimpleImageViewBox(SimpleViewBox):
+    export = QtCore.pyqtSignal(str)
+
     def raiseContextMenu(self, ev):
-        # nothing
+        menu = self.menu
+        menu.clear()
+        menu.addAction("Save event image as PNG",
+                       lambda: self.export.emit("png"))
+
+        pos = ev.screenPos()
+        menu.popup(QtCore.QPoint(pos.x(), pos.y()))
         return True