Deprecate unused/unnecessary modules (#1576)

* Deprecate ordereddict module

* Import OrderedDict from collections module instead of pgcollections

* Deprecate pgcollections module

* Deprecate lru_cache module

A simpler recipe exists from the standard library using OrderedDict.

* Deprecate pil_fix module

* Python 3.7 compatibility fix

* Avoid or suppress deprecation warnings in tests

examples/ExampleApp.py

@@ -6,7 +6,7 @@ import subprocess
 from argparse import Namespace
 import pyqtgraph as pg
 from pyqtgraph.Qt import QtGui, QtCore, QT_LIB
-from pyqtgraph.pgcollections import OrderedDict
+from collections import OrderedDict
 from .utils import examples
 
 path = os.path.abspath(os.path.dirname(__file__))

pyqtgraph/configfile.py

@@ -11,7 +11,7 @@ as it can be converted to/from a string using repr and eval.
 
 import re, os, sys, datetime
 import numpy
-from .pgcollections import OrderedDict
+from collections import OrderedDict
 from . import units
 from .python2_3 import asUnicode, basestring
 from .Qt import QtCore

pyqtgraph/dockarea/tests/test_dockarea.py

@@ -2,7 +2,7 @@
 
 import pytest
 import pyqtgraph as pg
-from pyqtgraph.ordereddict import OrderedDict
+from collections import OrderedDict
 pg.mkQApp()
 
 import pyqtgraph.dockarea as da

pyqtgraph/flowchart/Flowchart.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 from ..Qt import QtCore, QtGui, QT_LIB
 from .Node import *
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from ..widgets.TreeWidget import *
 from .. import FileDialog, DataTreeWidget
 

pyqtgraph/flowchart/Node.py

@@ -3,7 +3,7 @@ from ..Qt import QtCore, QtGui, QtWidgets
 from ..graphicsItems.GraphicsObject import GraphicsObject
 from .. import functions as fn
 from .Terminal import *
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from ..debug import *
 import numpy as np
 import warnings

pyqtgraph/flowchart/NodeLibrary.py

@@ -1,4 +1,4 @@
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .Node import Node
 
 def isNodeClass(cls):

pyqtgraph/flowchart/library/__init__.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-from ...pgcollections import OrderedDict
+from collections import OrderedDict
 import os, types
 from ...debug import printExc
 from ..NodeLibrary import NodeLibrary, isNodeClass

pyqtgraph/functions.py

@@ -21,7 +21,7 @@ from . import debug, reload
 from .Qt import QtGui, QtCore, QT_LIB, QtVersion
 from . import Qt
 from .metaarray import MetaArray
-from .pgcollections import OrderedDict
+from collections import OrderedDict
 from .python2_3 import asUnicode, basestring
 
 Colors = {

pyqtgraph/graphicsItems/DateAxisItem.py

@@ -4,7 +4,7 @@ import time
 from datetime import datetime, timedelta
 
 from .AxisItem import AxisItem
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 
 __all__ = ['DateAxisItem']
 

pyqtgraph/graphicsItems/GradientEditorItem.py

@@ -7,7 +7,7 @@ from .. import functions as fn
 from .GraphicsObject import GraphicsObject
 from .GraphicsWidget import GraphicsWidget
 from ..widgets.SpinBox import SpinBox
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from ..colormap import ColorMap
 
 translate = QtCore.QCoreApplication.translate

pyqtgraph/graphicsItems/GraphicsItem.py

@@ -1,4 +1,5 @@
 import warnings
+from collections import OrderedDict
 from functools import reduce
 from ..Qt import QtGui, QtCore, isQObjectAlive
 from ..GraphicsScene import GraphicsScene
@@ -6,7 +7,29 @@ from ..Point import Point
 from .. import functions as fn
 import weakref
 import operator
-from ..util.lru_cache import LRUCache
+
+
+# Recipe from https://docs.python.org/3.8/library/collections.html#collections.OrderedDict
+# slightly adapted for Python 3.7 compatibility
+class LRU(OrderedDict):
+    'Limit size, evicting the least recently looked-up key when full'
+
+    def __init__(self, maxsize=128, *args, **kwds):
+        self.maxsize = maxsize
+        super().__init__(*args, **kwds)
+
+    def __getitem__(self, key):
+        value = super().__getitem__(key)
+        self.move_to_end(key)
+        return value
+
+    def __setitem__(self, key, value):
+        if key in self:
+            self.move_to_end(key)
+        super().__setitem__(key, value)
+        if len(self) > self.maxsize:
+            oldest = next(iter(self))
+            del self[oldest]
 
 
 class GraphicsItem(object):
@@ -20,7 +43,7 @@ class GraphicsItem(object):
 
     The GraphicsView system places a lot of emphasis on the notion that the graphics within the scene should be device independent--you should be able to take the same graphics and display them on screens of different resolutions, printers, export to SVG, etc. This is nice in principle, but causes me a lot of headache in practice. It means that I have to circumvent all the device-independent expectations any time I want to operate in pixel coordinates rather than arbitrary scene coordinates. A lot of the code in GraphicsItem is devoted to this task--keeping track of view widgets and device transforms, computing the size and shape of a pixel in local item coordinates, etc. Note that in item coordinates, a pixel does not have to be square or even rectangular, so just asking how to increase a bounding rect by 2px can be a rather complex task.
     """
-    _pixelVectorGlobalCache = LRUCache(100, 70)
+    _pixelVectorGlobalCache = LRU(100)
 
     def __init__(self, register=None):
         if not hasattr(self, '_qtBaseClass'):

pyqtgraph/graphicsItems/ScatterPlotItem.py

@@ -14,7 +14,7 @@ from .. import functions as fn
 from .GraphicsItem import GraphicsItem
 from .GraphicsObject import GraphicsObject
 from .. import getConfigOption
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .. import debug
 from ..python2_3 import basestring
 

pyqtgraph/ordereddict.py

@@ -20,6 +20,12 @@
 #     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 #     OTHER DEALINGS IN THE SOFTWARE.
 
+import warnings
+warnings.warn(
+    "OrderedDict is in the standard library for supported versions of Python. Will be removed in 0.13",
+    DeprecationWarning, stacklevel=2
+)
+
 import sys
 if sys.version[0] > '2':
     from collections import OrderedDict

pyqtgraph/parametertree/Parameter.py

@@ -2,7 +2,7 @@
 from .. import functions as fn
 from ..Qt import QtGui, QtCore
 import os, weakref, re
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from ..python2_3 import asUnicode, basestring
 from .ParameterItem import ParameterItem
 import warnings

pyqtgraph/parametertree/SystemSolver.py

@@ -1,4 +1,4 @@
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 import numpy as np
 import copy
 

pyqtgraph/parametertree/parameterTypes.py

@@ -8,7 +8,7 @@ from ..widgets.ColorButton import ColorButton
 from ..colormap import ColorMap
 from .. import icons as icons
 from .. import functions as fn
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 
 
 class WidgetParameterItem(ParameterItem):

pyqtgraph/pgcollections.py

@@ -10,15 +10,17 @@ Includes:
   - ThreadsafeDict, ThreadsafeList - Self-mutexed data structures
 """
 
+import warnings
+warnings.warn(
+    "None of these are used in pyqtgraph. Will be removed in 0.13",
+    DeprecationWarning, stacklevel=2
+)
+
 import threading
 import sys
 import copy
 
-try:
-    from collections import OrderedDict
-except ImportError:
-    # fallback: try to use the ordereddict backport when using python 2.6
-    from ordereddict import OrderedDict
+from collections import OrderedDict
 
 try:
     from collections.abc import Sequence

pyqtgraph/util/lru_cache.py

@@ -1,3 +1,9 @@
+import warnings
+warnings.warn(
+    "No longer used in pyqtgraph. Will be removed in 0.13",
+    DeprecationWarning, stacklevel=2
+)
+
 import operator
 import sys
 import itertools

pyqtgraph/util/pil_fix.py

@@ -5,6 +5,12 @@ This works by patching objects in the PIL namespace; no files are
 modified.
 """
 
+import warnings
+warnings.warn(
+    "Not used in pyqtgraph. Will be removed in 0.13",
+    DeprecationWarning, stacklevel=2
+)
+
 from PIL import Image
 
 if Image.VERSION == '1.1.7':

pyqtgraph/util/tests/test_lru_cache.py

@@ -1,4 +1,9 @@
-from pyqtgraph.util.lru_cache import LRUCache
+import warnings
+
+with warnings.catch_warnings():
+    warnings.simplefilter('ignore')
+    from pyqtgraph.util.lru_cache import LRUCache
+
 
 def testLRU():
     lru = LRUCache(2, 1)

pyqtgraph/widgets/ColorMapWidget.py

@@ -1,7 +1,7 @@
 from ..Qt import QtGui, QtCore
 from .. import parametertree as ptree
 import numpy as np
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .. import functions as fn
 
 __all__ = ['ColorMapWidget']

pyqtgraph/widgets/ComboBox.py

@@ -1,7 +1,7 @@
 import sys
 from ..Qt import QtGui, QtCore
 from ..SignalProxy import SignalProxy
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from ..python2_3 import asUnicode, basestring
 
 

pyqtgraph/widgets/DataFilterWidget.py

@@ -1,7 +1,7 @@
 from ..Qt import QtGui, QtCore
 from .. import parametertree as ptree
 import numpy as np
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .. import functions as fn
 from ..python2_3 import basestring
 

pyqtgraph/widgets/DataTreeWidget.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from ..Qt import QtGui, QtCore
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .TableWidget import TableWidget
 from ..python2_3 import asUnicode
 import types, traceback

pyqtgraph/widgets/DiffTreeWidget.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from ..Qt import QtGui, QtCore
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 from .DataTreeWidget import DataTreeWidget
 from .. import functions as fn
 import types, traceback

pyqtgraph/widgets/ScatterPlotWidget.py

@@ -7,7 +7,7 @@ from .. import functions as fn
 from .. import getConfigOption
 from ..graphicsItems.TextItem import TextItem
 import numpy as np
-from ..pgcollections import OrderedDict
+from collections import OrderedDict
 
 __all__ = ['ScatterPlotWidget']
 

pyqtgraph/widgets/tests/test_tablewidget.py

@@ -1,6 +1,6 @@
 import pyqtgraph as pg
 import numpy as np
-from pyqtgraph.pgcollections import OrderedDict
+from collections import OrderedDict
 
 app = pg.mkQApp()