From 14a2b5d8f3f021219ef3ea09c90eeda78f539476 Mon Sep 17 00:00:00 2001
From: Phil Schaf <flying-sheep@web.de>
Date: Tue, 30 Dec 2014 14:20:21 +0100
Subject: [PATCH] fixed Qt5 compat

---
 skimage/viewer/qt.py         | 16 +++++++++++++---
 skimage/viewer/utils/core.py | 22 ++++++++--------------
 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/skimage/viewer/qt.py b/skimage/viewer/qt.py
index 240e794c..0f6f5616 100644
--- a/skimage/viewer/qt.py
+++ b/skimage/viewer/qt.py
@@ -1,11 +1,10 @@
-has_qt = True
-
 try:
-    from matplotlib.backends.qt_compat import QtGui, QtCore, QtWidgets
+    from matplotlib.backends.qt_compat import QtGui, QtCore, QtWidgets, QT_RC_MAJOR_VERSION as has_qt
 except ImportError:
     try:
         from matplotlib.backends.qt4_compat import QtGui, QtCore
         QtWidgets = QtGui
+        has_qt = 4
     except ImportError:
         # Mock objects
         class QtGui_cls(object):
@@ -28,5 +27,16 @@ except ImportError:
 
         has_qt = False
 
+if has_qt == 5:
+    from matplotlib.backends.backend_qt5 import FigureManagerQT
+    from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
+elif has_qt == 4:
+    from matplotlib.backends.backend_qt4 import FigureManagerQT
+    from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg
+else:
+    assert not has_qt, 'Unsupported Qt version {0}'.format(has_qt)
+    FigureManagerQT = object
+    FigureCanvasQTAgg = object
+
 Qt = QtCore.Qt
 Signal = QtCore.Signal
diff --git a/skimage/viewer/utils/core.py b/skimage/viewer/utils/core.py
index 517370e1..524e9b61 100644
--- a/skimage/viewer/utils/core.py
+++ b/skimage/viewer/utils/core.py
@@ -1,21 +1,15 @@
 import warnings
 
 import numpy as np
-from skimage.viewer.qt import QtGui, has_qt
+from skimage.viewer.qt import QtWidgets, has_qt, FigureManagerQT, FigureCanvasQTAgg
 import matplotlib as mpl
 from matplotlib.figure import Figure
 from matplotlib import _pylab_helpers
 from matplotlib.colors import LinearSegmentedColormap
 
-if has_qt:
-    from matplotlib.backends.backend_qt4 import FigureManagerQT
-    from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg
-    if 'agg' not in mpl.get_backend().lower():
-        warnings.warn("Recommended matplotlib backend is `Agg` for full "
-              "skimage.viewer functionality.")
-else:
-    FigureManagerQT = object
-    FigureCanvasQTAgg = object
+if has_qt and 'agg' not in mpl.get_backend().lower():
+    warnings.warn("Recommended matplotlib backend is `Agg` for full "
+                  "skimage.viewer functionality.")
 
 
 __all__ = ['init_qtapp', 'start_qtapp', 'RequiredAttr', 'figimage',
@@ -32,9 +26,9 @@ def init_qtapp():
     The QApplication needs to be initialized before creating any QWidgets
     """
     global QApp
-    QApp = QtGui.QApplication.instance()
+    QApp = QtWidgets.QApplication.instance()
     if QApp is None:
-        QApp = QtGui.QApplication([])
+        QApp = QtWidgets.QApplication([])
     return QApp
 
 
@@ -121,8 +115,8 @@ class FigureCanvas(FigureCanvasQTAgg):
         self.fig = figure
         FigureCanvasQTAgg.__init__(self, self.fig)
         FigureCanvasQTAgg.setSizePolicy(self,
-                                        QtGui.QSizePolicy.Expanding,
-                                        QtGui.QSizePolicy.Expanding)
+                                        QtWidgets.QSizePolicy.Expanding,
+                                        QtWidgets.QSizePolicy.Expanding)
         FigureCanvasQTAgg.updateGeometry(self)
 
     def resizeEvent(self, event):