Do not use ImportError behaviour in viewer

Conflicts:
	skimage/viewer/tests/test_tools.py

skimage/viewer/__init__.py

@@ -1,5 +1,6 @@
 import warnings
-try:
-    from .viewers import ImageViewer, CollectionViewer
-except ImportError as e:
+from .viewers import ImageViewer, CollectionViewer
+from .qt import has_qt
+
+if not has_qt:
     warnings.warn('Viewer requires Qt')

skimage/viewer/qt.py

@@ -1,8 +1,25 @@
+has_qt = True
+
 try:
     from matplotlib.backends.qt_compat import QtGui, QtCore, QtWidgets
 except ImportError:
-    from matplotlib.backends.qt4_compat import QtGui, QtCore
-    QtWidgets = QtGui
+    try:
+        from matplotlib.backends.qt4_compat import QtGui, QtCore
+        QtWidgets = QtGui
+    except ImportError:
+        # Mock objects
+        class QtGui(object):
+            QMainWindow = object
+            QDialog = object
+            QWidget = object
+
+        class QtCore(object):
+            Signal = object
+            Qt = object
+
+        QtWidgets = QtGui
+
+        has_qt = False
 
 Qt = QtCore.Qt
 Signal = QtCore.Signal

skimage/viewer/tests/test_plugins.py

@@ -4,15 +4,12 @@ import skimage
 import skimage.data as data
 from skimage.filters.rank import median
 from skimage.morphology import disk
-try:
-    from skimage.viewer import ImageViewer
-    from skimage.viewer.plugins.base import Plugin
-    from skimage.viewer.widgets import Slider
-    from skimage.viewer.plugins import (
-        LineProfile, Measure, CannyPlugin, LabelPainter, Crop, ColorHistogram,
-        PlotPlugin)
-except ImportError:
-    ImageViewer is None
+from skimage.viewer import ImageViewer, has_qt
+from skimage.viewer.plugins.base import Plugin
+from skimage.viewer.widgets import Slider
+from skimage.viewer.plugins import (
+    LineProfile, Measure, CannyPlugin, LabelPainter, Crop, ColorHistogram,
+    PlotPlugin)
 from numpy.testing import assert_equal, assert_allclose, assert_almost_equal
 from numpy.testing.decorators import skipif
 <<<<<<< HEAD
@@ -33,7 +30,7 @@ def setup_line_profile(image, limits='image'):
     return plugin
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_line_profile():
     """ Test a line profile using an ndim=2 image"""
     plugin = setup_line_profile(data.camera())
@@ -47,7 +44,7 @@ def test_line_profile():
     assert_allclose(scan_data.mean(), 0.2812, rtol=1e-3)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_line_profile_rgb():
     """ Test a line profile using an ndim=3 image"""
     plugin = setup_line_profile(data.chelsea(), limits=None)
@@ -62,7 +59,7 @@ def test_line_profile_rgb():
     assert_allclose(scan_data.mean(), 0.4359, rtol=1e-3)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_line_profile_dynamic():
     """Test a line profile updating after an image transform"""
     image = data.coins()[:-50, :]  # shave some off to make the line lower
@@ -88,7 +85,7 @@ def test_line_profile_dynamic():
     assert_almost_equal(np.max(line) - np.min(line), 0.639, 1)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_measure():
     image = data.camera()
     viewer = ImageViewer(image)
@@ -100,7 +97,7 @@ def test_measure():
     assert_equal(str(m._angle.text[:5]), '135.0')
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_canny():
     image = data.camera()
     viewer = ImageViewer(image)
@@ -113,7 +110,7 @@ def test_canny():
     assert edges.sum() == 2852
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_label_painter():
     image = data.camera()
     moon = data.moon()
@@ -131,7 +128,7 @@ def test_label_painter():
     assert_equal(lp.paint_tool.shape, moon.shape)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_crop():
     image = data.camera()
     viewer = ImageViewer(image)
@@ -142,7 +139,7 @@ def test_crop():
     assert_equal(viewer.image.shape, (101, 101))
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_color_histogram():
     image = skimage.img_as_float(data.load('color.png'))
     viewer = ImageViewer(image)
@@ -154,7 +151,7 @@ def test_color_histogram():
     assert_almost_equal(viewer.image.std(), 0.325, 3)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_plot_plugin():
     viewer = ImageViewer(data.moon())
     plugin = PlotPlugin(image_filter=lambda x: x)
@@ -166,7 +163,7 @@ def test_plot_plugin():
     viewer.close()
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_plugin():
     img = skimage.img_as_float(data.moon())
     viewer = ImageViewer(img)

skimage/viewer/tests/test_tools.py

@@ -4,23 +4,12 @@ import numpy as np
 from numpy.testing import assert_equal
 from numpy.testing.decorators import skipif
 from skimage import data
-<<<<<<< HEAD
-from skimage.viewer import ImageViewer, viewer_available
+from skimage.viewer import ImageViewer, has_qt
 from skimage.viewer.canvastools import (
     LineTool, ThickLineTool, RectangleTool, PaintTool)
 from skimage.viewer.canvastools.base import CanvasToolBase
 from matplotlib.testing.decorators import cleanup
 
-=======
-try:
-    from skimage.viewer import ImageViewer
-    from skimage.viewer.canvastools import (
-        LineTool, ThickLineTool, RectangleTool, PaintTool)
-    from skimage.viewer.canvastools.base import CanvasToolBase
-except ImportError:
-    ImageViewer = None
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
-
 
 def get_end_points(image):
     h, w = image.shape[0:2]
@@ -84,12 +73,8 @@ def do_event(viewer, etype, button=1, xdata=0, ydata=0, key=None):
     func(event)
 
 
-<<<<<<< HEAD
 @cleanup
-@skipif(not viewer_available)
-=======
-@skipif(ImageViewer is None)
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
+@skipif(not has_qt)
 def test_line_tool():
     img = data.camera()
     viewer = ImageViewer(img)
@@ -114,12 +99,8 @@ def test_line_tool():
     assert_equal(tool.geometry, np.array([[100, 100], [10, 10]]))
 
 
-<<<<<<< HEAD
 @cleanup
-@skipif(not viewer_available)
-=======
-@skipif(ImageViewer is None)
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
+@skipif(not has_qt)
 def test_thick_line_tool():
     img = data.camera()
     viewer = ImageViewer(img)
@@ -142,12 +123,8 @@ def test_thick_line_tool():
     assert_equal(tool.linewidth, 1)
 
 
-<<<<<<< HEAD
 @cleanup
-@skipif(not viewer_available)
-=======
-@skipif(ImageViewer is None)
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
+@skipif(not has_qt)
 def test_rect_tool():
     img = data.camera()
     viewer = ImageViewer(img)
@@ -175,12 +152,8 @@ def test_rect_tool():
     assert_equal(tool.geometry, [10, 100,  10, 100])
 
 
-<<<<<<< HEAD
 @cleanup
-@skipif(not viewer_available)
-=======
-@skipif(ImageViewer is None)
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
+@skipif(not has_qt)
 def test_paint_tool():
     img = data.moon()
     viewer = ImageViewer(img)
@@ -213,12 +186,8 @@ def test_paint_tool():
     assert_equal(tool.overlay.sum(), 0)
 
 
-<<<<<<< HEAD
 @cleanup
-@skipif(not viewer_available)
-=======
-@skipif(ImageViewer is None)
->>>>>>> 7e2fdf7... Update viewer for PyQt5 compatibility
+@skipif(not has_qt)
 def test_base_tool():
     img = data.moon()
     viewer = ImageViewer(img)

skimage/viewer/tests/test_utils.py

@@ -1,14 +1,11 @@
 # -*- coding: utf-8 -*-
-try:
-    from skimage.viewer import utils
-    from skimage.viewer.utils import dialogs
-    from skimage.viewer.qt import QtCore, QtGui
-except ImportError:
-    QtCore = None
+from skimage.viewer import utils
+from skimage.viewer.utils import dialogs
+from skimage.viewer.qt import QtCore, QtGui, has_qt
 from numpy.testing.decorators import skipif
 
 
-@skipif(QtCore is None)
+@skipif(not has_qt)
 def test_event_loop():
     utils.init_qtapp()
     timer = QtCore.QTimer()
@@ -16,7 +13,7 @@ def test_event_loop():
     utils.start_qtapp()
 
 
-@skipif(QtCore is None)
+@skipif(not has_qt)
 def test_format_filename():
     fname = dialogs._format_filename(('apple', 2))
     assert fname == 'apple'
@@ -24,7 +21,7 @@ def test_format_filename():
     assert fname is None
 
 
-@skipif(QtCore is None)
+@skipif(not has_qt)
 def test_open_file_dialog():
     utils.init_qtapp()
     timer = QtCore.QTimer()
@@ -33,7 +30,7 @@ def test_open_file_dialog():
     assert filename is None
 
 
-@skipif(QtCore is None)
+@skipif(not has_qt)
 def test_save_file_dialog():
     utils.init_qtapp()
     timer = QtCore.QTimer()

skimage/viewer/tests/test_viewer.py

@@ -1,11 +1,10 @@
 
 from skimage import data
-try:
-    from skimage.viewer.qt import QtGui, QtCore
-    from skimage.viewer import ImageViewer, CollectionViewer
-    from skimage.viewer.plugins import OverlayPlugin
-except ImportError:
-    ImageViewer = None
+
+from skimage.viewer.qt import QtGui, QtCore, has_qt
+from skimage.viewer import ImageViewer, CollectionViewer
+from skimage.viewer.plugins import OverlayPlugin
+
 from skimage.transform import pyramid_gaussian
 from skimage.filters import sobel
 from numpy.testing import assert_equal
@@ -14,7 +13,7 @@ from skimage._shared.version_requirements import is_installed
 from skimage._shared._warnings import expected_warnings
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_viewer():
     astro = data.astronaut()
     coins = data.coins()
@@ -41,7 +40,7 @@ def make_key_event(key):
                            QtCore.Qt.NoModifier)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_collection_viewer():
 
     img = data.astronaut()
@@ -57,7 +56,7 @@ def test_collection_viewer():
     view._format_coord(10, 10)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 @skipif(not is_installed('matplotlib', '>=1.2'))
 def test_viewer_with_overlay():
     img = data.coins()

skimage/viewer/tests/test_widgets.py

@@ -1,14 +1,13 @@
 
 import os
 from skimage import data, img_as_float, io, img_as_uint
-try:
-    from skimage.viewer import ImageViewer
-    from skimage.viewer.qt import QtGui, QtCore
-    from skimage.viewer.widgets import (
-        Slider, OKCancelButtons, SaveButtons, ComboBox, CheckBox, Text)
-    from skimage.viewer.plugins.base import Plugin
-except ImportError:
-    ImageViewer = None
+
+from skimage.viewer import ImageViewer
+from skimage.viewer.qt import QtGui, QtCore, has_qt
+from skimage.viewer.widgets import (
+    Slider, OKCancelButtons, SaveButtons, ComboBox, CheckBox, Text)
+from skimage.viewer.plugins.base import Plugin
+
 from numpy.testing import assert_almost_equal, assert_equal
 from numpy.testing.decorators import skipif
 from skimage._shared._warnings import expected_warnings
@@ -21,7 +20,7 @@ def get_image_viewer():
     return viewer
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_check_box():
     viewer = get_image_viewer()
     cb = CheckBox('hello', value=True, alignment='left')
@@ -36,7 +35,7 @@ def test_check_box():
     assert_equal(cb.val, False)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_combo_box():
     viewer = get_image_viewer()
     cb = ComboBox('hello', ('a', 'b', 'c'))
@@ -49,7 +48,7 @@ def test_combo_box():
     assert_equal(cb.index, 2)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_text_widget():
     viewer = get_image_viewer()
     txt = Text('hello', 'hello, world!')
@@ -60,7 +59,7 @@ def test_text_widget():
     assert_equal(str(txt.text), 'goodbye, world!')
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_slider_int():
     viewer = get_image_viewer()
     sld = Slider('radius', 2, 10, value_type='int')
@@ -74,7 +73,7 @@ def test_slider_int():
     assert_equal(sld.val, 5)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_slider_float():
     viewer = get_image_viewer()
     sld = Slider('alpha', 2.1, 3.1, value=2.1, value_type='float',
@@ -89,7 +88,7 @@ def test_slider_float():
     assert_almost_equal(sld.val, 2.5, 2)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_save_buttons():
     viewer = get_image_viewer()
     sv = SaveButtons()
@@ -117,7 +116,7 @@ def test_save_buttons():
     os.remove(filename)
 
 
-@skipif(ImageViewer is None)
+@skipif(not has_qt)
 def test_ok_buttons():
     viewer = get_image_viewer()
     ok = OKCancelButtons()