Merge pull request #5032 from irgolic/nice-hscroll-datatable

Slow horizontal scrolling in `QTableView`s

Orange/widgets/data/owtable.py

@@ -363,7 +363,7 @@ def table_selection_to_list(table):
 TableSlot = namedtuple("TableSlot", ["input_id", "table", "summary", "view"])
 
 
-class TableView(QTableView):
+class TableView(gui.HScrollStepMixin, QTableView):
     #: Signal emitted when selection finished. It is not emitted during
     #: mouse drag selection updates.
     selectionFinished = Signal()

Orange/widgets/evaluate/owpredictions.py

@@ -1209,7 +1209,7 @@ def reset(self):
         self.clearCurrentIndex()
 
 
-class TableView(QTableView):
+class TableView(gui.HScrollStepMixin, QTableView):
     MaxSizeHintSamples = 1000
 
     def sizeHintForColumn(self, column):

Orange/widgets/gui.py

@@ -4,13 +4,14 @@
 import math
 
 import logging
+import sys
 import warnings
 import weakref
 from collections.abc import Sequence
 
 from AnyQt import QtWidgets, QtCore, QtGui
 from AnyQt.QtCore import Qt, QSize, QItemSelection
-from AnyQt.QtGui import QColor
+from AnyQt.QtGui import QColor, QWheelEvent
 from AnyQt.QtWidgets import QWidget, QItemDelegate, QListView, QComboBox
 
 # re-export relevant objects
@@ -658,3 +659,28 @@ def paint(self, painter, option, index):
 
 from Orange.widgets.utils.colorpalettes import patch_variable_colors
 patch_variable_colors()
+
+
+class HScrollStepMixin:
+    """
+    Overrides default TableView horizontal behavior (scrolls 1 page at a time)
+    to a friendlier scroll speed akin to that of vertical scrolling.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.horizontalScrollBar().setSingleStep(20)
+
+    def wheelEvent(self, event: QWheelEvent):
+        if event.source() == Qt.MouseEventNotSynthesized and \
+                (event.modifiers() & Qt.ShiftModifier and sys.platform == 'darwin' or
+                 event.modifiers() & Qt.AltModifier and sys.platform != 'darwin'):
+            new_event = QWheelEvent(
+                event.pos(), event.globalPos(), event.pixelDelta(),
+                event.angleDelta(), event.buttons(), Qt.NoModifier,
+                event.phase(), event.inverted(), Qt.MouseEventSynthesizedByApplication
+            )
+            event.accept()
+            super().wheelEvent(new_event)
+        else:
+            super().wheelEvent(event)

Orange/widgets/unsupervised/owdistancematrix.py

@@ -153,6 +153,10 @@ def set_selected_items(self, inds):
         self.select(selection, QItemSelectionModel.ClearAndSelect)
 
 
+class TableView(gui.HScrollStepMixin, QTableView):
+    pass
+
+
 class DistanceMatrixContextHandler(ContextHandler):
     @staticmethod
     def _var_names(annotations):
@@ -213,7 +217,7 @@ def __init__(self):
         self.items = None
 
         self.tablemodel = DistanceMatrixModel()
-        view = self.tableview = QTableView()
+        view = self.tableview = TableView()
         view.setEditTriggers(QTableView.NoEditTriggers)
         view.setItemDelegate(TableBorderItem())
         view.setModel(self.tablemodel)