Add smart window-layout for multi-viewer display

skimage/viewer/plugins/base.py

@@ -76,7 +76,7 @@ class Plugin(QtGui.QDialog):
 
     # Signals used when viewers are linked to the Plugin output.
     image_updated = pyqtSignal(np.ndarray)
-    _started = pyqtSignal()
+    _started = pyqtSignal(int)
 
     def __init__(self, image_filter=None, height=0, width=400, useblit=True,
                  dock='bottom'):
@@ -201,7 +201,9 @@ class Plugin(QtGui.QDialog):
     def show(self, main_window=True):
         """Show plugin."""
         super(Plugin, self).show()
-        self._started.emit()
+        size = self.frameGeometry()
+        x_hint = size.x() + size.width()
+        self._started.emit(x_hint)
 
     def closeEvent(self, event):
         """On close disconnect all artists and events from ImageViewer.

skimage/viewer/viewers/core.py

@@ -190,21 +190,8 @@ class ImageViewer(QtGui.QMainWindow):
     def closeEvent(self, event):
         self.close()
 
-    def auto_layout(self):
-        """Move viewer to top-left and align plugin on right edge of viewer."""
-        size = self.frameGeometry()
-        self.move(0, 0)
-        # w = size.width()
-        # h = size.height()
-        # x = 0
-        # y = h
-        # #TODO: Layout isn't quite correct for multiple plugins (overlaps).
-        # for p in self.plugins:
-            # p.move(x, y)
-            # y += p.frameGeometry().height()
-
-    def _show(self):
-        self.auto_layout()
+    def _show(self, x=0):
+        self.move(x, 0)
         for p in self.plugins:
             p.show()
         super(ImageViewer, self).show()