How can I modify a QtableWidget which is on a QMainWindow from a QGraphicsView method? - pyqt5

Question

Essentially I created a QMainWindow which has a Splitter which, in turn, has on its left side a QTableWidget and on the right side a QGraphicsView.
I have also created a method to zoom in and out in the QGraphicsView. Now, I want to resize the height of the rows depending on the amount of zoom provided by the user.
class MyWindow(QMainWindow):
def __init__(self):
super(MyWindow, self).__init__()
# Main characteristics of the window
self.setGeometry(50, 50, 1000, 700)
#User Interface
self.initUI()
def initUI(self):
#Creation of table and timeline splitter
self.table_and_view_splitter = QtWidgets.QSplitter()
self.table_and_view_splitter.setOrientation(QtCore.Qt.Horizontal)
#Creation of metadata table
self.create_table()
self.table_and_view_splitter.addWidget(self.table)
#Creation of View and Scene for timeline
self.create_view()
self.table_and_view_splitter.addWidget(self.view)
# Creation of vertical splitter
self.vertical_splitter = QtWidgets.QSplitter()
self.vertical_splitter.setOrientation(QtCore.Qt.Vertical)
self.vertical_splitter.insertWidget(1, self.table_and_view_splitter)
# Choosing the sizes of the upper and lower widgets of the Qsplitter
self.sizes_list = [100, 5000]
self.vertical_splitter.setSizes(self.sizes_list)
self.setCentralWidget(self.vertical_splitter)
def create_table(self):
self.table = QTableWidget()
self.table.setColumnCount(3)
self.table.setRowCount(100)
for i in range(self.table.rowCount()):
self.table.setRowHeight(i, 10)
def create_view(self):
self.view = viewFor()
self.scene = QtWidgets.QGraphicsScene()
self.scene.addEllipse(1, 1, 10, 10)
self.view.setScene(self.scene)
class viewFor(QGraphicsView):
def __init__(self):
super(viewFor, self).__init__()
self.drag = False
self.setTransformationAnchor(self.NoAnchor)
def wheelEvent(self, event):
self.setTransformationAnchor(self.AnchorUnderMouse)
zoom_in_factor = 1.1
zoom_out_factor = 1 / zoom_in_factor
# Save the scene pos
old_position = self.mapToScene(event.pos())
if QApplication.keyboardModifiers() == Qt.ControlModifier:# CTRL + Scroll -> X and Y Zoom
# Zoom
if event.angleDelta().y() > 0:
zoom_factor = zoom_in_factor
else:
zoom_factor = zoom_out_factor
self.scale(zoom_factor, zoom_factor)
#HERE I WANT TO RESIZE THE ROWS HEIGHT ACCORDING TO THE zoom_factor
# Get the new position
new_position = self.mapToScene(event.pos())
# Move scene to old position
delta = new_position - old_position
self.translate(delta.x(), delta.y())
else:# Only Scroll -> only X Zoom
# Zoom
if event.angleDelta().y() > 0:
zoom_factor = zoom_in_factor
else:
zoom_factor = zoom_out_factor
self.scale(zoom_factor, 1)
# Get the new position
new_position = self.mapToScene(event.pos())
# Move scene to old position
delta = new_position - old_position
self.translate(delta.x(), delta.y())
app = QApplication([])
foo = MyWindow()
foo.show()
sys.exit(app.exec_())

Answer 1

You need to emit a signal whenever the scale is changed, and QHeaderView.setDefaultSectionSize() for the vertical header. Note that you should probably use setSectionResizeMode(QHeaderView.Fixed) to avoid user resizing (or just leave it to Interactive, but certainly don't use Stretch or ResizeToContents).
You should obviously ensure that the range is valid or find your own algorithm (that sanitizes the value to a valid range that has at least a minimum of 1).
In this case I used the default original value and multiplied it using the scale factor of the view's transformation (see QTransform > rendering graphics about the meaning of the transformation matrix).
class MyWindow(QtWidgets.QMainWindow):
def __init__(self):
super(MyWindow, self).__init__()
# Main characteristics of the window
self.setGeometry(50, 50, 1000, 700)
#User Interface
self.initUI()
self.view.scaleChanged.connect(self.resizeRows)
self.defaultSize = self.table.verticalHeader().defaultSectionSize()
def resizeRows(self, scale):
self.table.verticalHeader().setDefaultSectionSize(scale * self.defaultSize)
class viewFor(QtWidgets.QGraphicsView):
scaleChanged = QtCore.pyqtSignal(float)
# ...
def wheelEvent(self, event):
self.setTransformationAnchor(self.AnchorUnderMouse)
zoom_in_factor = 1.1
zoom_out_factor = 1 / zoom_in_factor
# Save the scene pos
old_position = self.mapToScene(event.pos())
if event.modifiers() == QtCore.Qt.ControlModifier:# CTRL + Scroll -> X and Y Zoom
# Zoom
if event.angleDelta().y() > 0:
zoom_factor = zoom_in_factor
else:
zoom_factor = zoom_out_factor
self.scale(zoom_factor, zoom_factor)
# emit the signal based on the transformation scale factor
self.scaleChanged.emit(self.transform().m11())
# ...
Note that you don't need to use QApplication.keyboardModifiers, as you can access modifiers() of all keyboard/mouse events.