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How to limit the rightest Gtk.TreeViewColumn's width inside a Gtk.ScrolledWindow?

I cannot prevent the rightest column of a Gtk.TreeView to expand.
As the real Gtk.TreeView may display a greater number of rows, making it usually somewhat greater than the screen's height, it is embedded in a Gtk.ScrolledWindow. This is required. Without it, attaching an empty grid at the right of the treeview, expanding itself horizontally, would fix the problem. Based on this idea, I've tried a workaround that introduces another difficulty (see below).
I have built a minimal working example from the example from https://python-gtk-3-tutorial.readthedocs.io/en/latest/treeview.html#filtering, without filtering nor buttons; and the columns are 80 px wide at least (this works) and their content is horizontally centered. This last detail makes the horizontal expansion of the rightest column visible. In the original example, it does expand too, but as everything is left aligned, this is not really visible. I'd liked to keep the columns' content centered, without seeing the rightest expanded.
This example is minimal, but contains some helping features: you'll find clickable column titles, that will display some information about the clicked column in the console; a remove button (works fine, remove the selected rows) and a paste button that allows to paste new rows from a selection (e.g. from selected lines from a spreadsheet, but there's nothing to check the data are correct, if you paste something that does not convert to int, it will simply crash).
Workaround
A workaround I've tried consist of gathering both the treeview and a horizontally expanding empty right grid at its right inside a grid that would be put inside the Gtk.ScrolledWindow. It works, but causes other subtle problems: in some situations, the treeview does not get refreshed (it happens after a while), yet nothing prevents the main loop to refresh the view (there's no other processing in the background, for instance). To experiment this workaround: comment and uncomment the lines as described in the code below; run the program via python script.py (if you need to install pygobject in a venv, see here), notice the rightest column does not expand to the right any longer, select the 3 first rows and press "remove", then from a spread sheet, select 3 lines of dummy integers as shown below and then press "paste". Scroll down to the last rows: you'll see most of the time that the 3 pasted lines do not show up, even if it is possible to scroll over the last row. Maybe one of them will show up after some time, then another... (or simply select a row, and they'll show up). Strangely, it happens if one has just removed as many lines as one wants to paste after the removal (3 removed, 3 pasted; or 4 removed, 4 pasted etc.).
Example spreadsheet selection:
Question
So, I'd prefer to avoid the workaround (I'm afraid I may find other situations triggering a bad refreshing of the treeview), that I could not fix itself (for instance, setting self.scrollable_treelist.set_propagate_natural_height(True) proved useless, maybe I'm not using it correctly though?) and only attach the treeview itself directly in the Gtk.ScrolledWindow. How to prevent the rightest column to expand, then?
(I've tried to use a fair amount of setters and properties of the cell renderers, the treeview, the treeview columns, the scrolled window, to no avail. Some of them are still in the code below.)
Any solution using and fixing the workaround above would be accepted though.
In any case, the treeview may be scrolled, and lines may be added and removed from it without any refreshing problem.
Source Code
import gi
try:
gi.require_version('Gtk', '3.0')
except ValueError:
raise
else:
from gi.repository import Gtk, Gdk
# ints to feed the store
data_list = [(i, 2 * i, 3 * i, 4 * i, 5 * i) for i in range(40)]
class AppWindow(Gtk.Window):
def __init__(self):
super().__init__(title="Treeview Columns Size Demo")
self.set_border_width(10)
# Setting up the self.grid in which the elements are to be positioned
self.grid = Gtk.Grid()
self.grid.set_column_homogeneous(True)
self.grid.set_row_homogeneous(True)
self.add(self.grid)
# Creating the ListStore model
self.store = Gtk.ListStore(int, int, int, int, int)
for data_ref in data_list:
self.store.append(list(data_ref))
# creating the treeview and adding the columns
self.treeview = Gtk.TreeView(model=self.store)
rend = Gtk.CellRendererText()
rend.set_alignment(0.5, 0.5)
for i, column_title in enumerate([f'n×{p}' for p in [1, 2, 3, 4, 5]]):
column = Gtk.TreeViewColumn(column_title, rend, text=i)
column.set_min_width(80)
# column.set_max_width(80)
# column.set_fixed_width(80)
# column.set_sizing(Gtk.TreeViewColumnSizing(1))
column.set_alignment(0.5)
column.set_clickable(True)
column.connect('clicked', self.on_column_clicked)
self.treeview.append_column(column)
self.treeview.set_hexpand(False)
self.treeview.get_selection().set_mode(Gtk.SelectionMode.MULTIPLE)
# Put the treeview in a scrolled window
self.scrollable_treelist = Gtk.ScrolledWindow()
self.scrollable_treelist.set_vexpand(True)
self.grid.attach(self.scrollable_treelist, 0, 0, 8, 10)
self.scrollable_treelist.add(self.treeview)
# WORKAROUND
# Alternatively, embed the treeview inside a grid containing an
# empty grid to the right of the treeview
# To try it: comment out the previous line; uncomment next lines
# scrolled_grid = Gtk.Grid()
# empty_grid = Gtk.Grid()
# empty_grid.set_hexpand(True)
# scrolled_grid.attach(self.treeview, 0, 0, 8, 10)
# scrolled_grid.attach_next_to(empty_grid, self.treeview,
# Gtk.PositionType.RIGHT, 1, 1)
# self.scrollable_treelist.add(scrolled_grid)
# self.scrollable_treelist.set_propagate_natural_height(True)
# Buttons
self.remove_button = Gtk.Button(label='Remove')
self.remove_button.connect('clicked', self.on_remove_clicked)
self.paste_button = Gtk.Button(label='Paste')
self.paste_button.connect('clicked', self.on_paste_clicked)
self.grid.attach_next_to(self.remove_button, self.scrollable_treelist,
Gtk.PositionType.TOP, 1, 1)
self.grid.attach_next_to(self.paste_button, self.remove_button,
Gtk.PositionType.RIGHT, 1, 1)
self.set_default_size(800, 500)
self.show_all()
# Clipboard (to insert several rows)
self.clip = Gtk.Clipboard.get(Gdk.SELECTION_PRIMARY)
self.clip2 = Gtk.Clipboard.get(Gdk.SELECTION_CLIPBOARD)
def on_column_clicked(self, col):
print(f'col.get_sizing()={col.get_sizing()}')
print(f'col.get_expand()={col.get_expand()}')
print(f'col.get_width()={col.get_width()}')
print(f'col.get_min_width()={col.get_min_width()}')
print(f'col.get_max_width()={col.get_max_width()}')
print(f'col.get_fixed_width()={col.get_fixed_width()}')
def on_remove_clicked(self, widget):
model, paths = self.treeview.get_selection().get_selected_rows()
refs = []
for path in paths:
refs.append(Gtk.TreeRowReference.new(model, path))
for ref in refs:
path = ref.get_path()
treeiter = model.get_iter(path)
model.remove(treeiter)
# print(f'AFTER REMOVAL, REMAINING ROWS={[str(r[0]) for r in model]}')
def on_paste_clicked(self, widget):
text = self.clip.wait_for_text()
if text is None:
text = self.clip2.wait_for_text()
if text is not None:
lines = text.split('\n') # separate the lines
lines = [tuple(L.split('\t')) for L in lines] # convert to tuples
print(f'PASTE LINES={lines}')
for line in lines:
if len(line) == 5:
line = tuple(int(value) for value in line)
self.store.append(line)
win = AppWindow()
win.connect("destroy", Gtk.main_quit)
win.show_all()
Gtk.main()

How to get the QModelIndex associated with the QCheckbox placed in the QTableWIdget

I have the following code to place a CheckBox in the first column of a list of items in a QTableWidget.
checkboxWidget = QWidget()
checkBox = QCheckBox(checkboxWidget)
checkBox.clicked.connect(self._check_changed)
#
# If the variable is in the monitored list
# check the checkbox
#
isMonitored = False
if (self._monitored_variables != None):
if (self._monitored_variables[name]):
isMonitored = True
if (isMonitored):
checkBox.setCheckState(Qt.CheckState.Checked)
else:
checkBox.setCheckState(Qt.CheckState.Unchecked)
layoutCheckbox = QHBoxLayout(checkboxWidget)
layoutCheckbox.addWidget(checkBox)
layoutCheckbox.setAlignment(Qt.AlignCenter)
layoutCheckbox.setContentsMargins(0, 0, 0, 0)
self._variables_view.setCellWidget(row,0, checkboxWidget)
I started with the answer to this question:
How should I connect CheckBox clicked signals in Table Widgets in PyQt5?
The difference that I have is that I want the CheckBox centered in the table cell, hence the extra controls.
The click handler looks like this:
def _check_changed(self):
cb = self.sender()
print(cb.parent())
ix = self._variables_view.indexAt(cb.pos())
print(ix.row(), ix.column(), cb.isChecked())
The problem I am facing is that the row/column is not correct.
How can I recover the row/column of the CheckBox that was clicked?

It seems that my previous answer was not explicit but I am going to take this answer to take it in a generic way that will work for all the classes that inherit from QAbstractItemView and any type of widget placed through the setCellWidget or setIndexWidget methods.
General case:
The key to the solution is to obtain the position of the widget that emits the signal with respect to the viewport of the QAbstractItemView, and then use indexAt to get the QModelIndex. This can be obtained by following the following steps:
Map any relative internal position of the widget to global coordinates.
Map global coordinates to local coordinate relative to the viewport.
use indexAt() with local coordinate.
gl = widget.mapToGlobal(QtCore.QPoint())
lp = view.viewport().mapFromGlobal(gp)
ix = view.indexAt(lp)
Specific case:
In this case, just do the following:
def _check_changed(self):
widget = self.sender()
gl = widget.mapToGlobal(QtCore.QPoint())
lp = self._variables_view.viewport().mapFromGlobal(gp)
ix = self._variables_view.indexAt(lp)

It seems the answer to my issues was rather simple. In the "indexAt" method the "cb.pos()" needs to be changed to "cb.parent().pos()".

How to fixed image when moving item in QGraphicsViewer

I am developing an image viewer using pyqt.
I want the image to be fixed when the box moved.
However, the image is pushed when the box tries to reach the viewer's side like this.
It was implemented using QGraphicsView, QGraphicsScene, and QGraphicsitem.
This is part of main class
self.scene_r = GraphicsScene()
self.scene_r.addPixmap(pix_resized)
self.resizedView.setScene(self.scene_r)
self.resizedView.centerOn(128,128)
This is QGraphicScene Class
class GraphicsScene(QGraphicsScene):
def __init__(self, parent=None):
QGraphicsScene.__init__(self)
rect_item = recItem(QRectF(0, 0, 100, 100))
rect_item.setFlag(QGraphicsItem.ItemIsMovable, True)
rect_item.setZValue(1)
rect_item.setPen(Qt.green)
self.addItem(rect_item)
I tried to override mouseMoveEvent() of QGraphicsRectItem class, but it failed.

That happens for two reasons:
Since you are making the item movable, you can move it freely, anywhere you want.
When the scene rectangle is smaller than the one visible in the view, the view tries to ensure that the whole scene rectangle stays visible, possibly by scrolling its contents.
Note that, unless explicitly set using setSceneRect() (on the scene or on the view, the results might differ), Qt automatically sets the scene rect implicitly to the bigger QRect that contains all visible graphics items.
There at least two possible solutions to your problem, which one to choose depends on what you need, and you can also decide to use both of them.
Explicitly set the sceneRect
You can set the sceneRect to a specific rectangle, an item, or all existing items. Note that, while in your case it won't change much if you set the rectangle for the scene or the view, in more complex cases (for example, multiple views showing the same scene) the result might differ.
# on the view
self.setSceneRect(self.scene_r.itemsBoundingRect())
# alternativaly, on the scene
self.setSceneRect(self.itemsBoundingRect())
Limit the area in which the item can be moved
In this case you can intercept the itemChange ItemPositionChange (note that the ItemSendsGeometryChanges flag must be set) and return an adjusted value before it is actually applied:
class RecItem(QGraphicsRectItem):
def __init__(self, *args):
super().__init__(*args)
self.setFlags(self.ItemSendsGeometryChanges)
def itemChange(self, change, value):
if change == self.ItemPositionChange:
sceneRect = self.scene().sceneRect()
newGeometry = self.boundingRect().translated(value)
# the item pen must be taken into account
halfPen = self.pen().width() / 2
if value.x() < sceneRect.x():
value.setX(sceneRect.x() + halfPen)
if value.y() < sceneRect.y():
value.setY(sceneRect.y() + halfPen)
if newGeometry.right() + halfPen > sceneRect.right():
value.setX(sceneRect.right() - newGeometry.width())
if newGeometry.bottom() + halfPen > sceneRect.bottom():
value.setY(sceneRect.bottom() - newGeometry.height())
return value
return super().itemChange(change, value)

Controlling dynamic properties in Shady according to video frames not time

I am trying to use Shady to present a sequence of image frames. I'm controlling the flow from another machine, so that I first instruct the machine running Shady to present the first frame, and later on to run the rest of the frames.
I create a World instance, and attach to it an animation callback function. Within this callback I listen for communications from the other machine (using UDP).
First I receive a command to load a given sequence (stored as a numpy array), and I do
def loadSequence(self, fname):
yy = np.load(fname)
pages = []
sz = yy.shape[0]
for j in range(yy.shape[1]/yy.shape[0]):
pages.append(yy[:, j*sz:(j+1)*sz])
deltax, deltay = (self.screen_px[0] - sz) / 2, (self.screen_px[1] - sz) / 2
if (self.sequence is None):
self.sequence = self.wind.Stimulus(pages, 'sequence', multipage=True, anchor=Shady.LOCATION.UPPER_LEFT, position=[deltax, deltay], visible=False)
else:
self.sequence.LoadPages(pages, visible=False)
When I receive the command to show the first frame, I then do:
def showFirstFrame(self, pars):
self.sequence.page = 0 if (pars[0] == 0) else (len(self.sequence.pages) - 1)
self.sequence.visible = True
But what do I do now to get the other frames to be be displayed? In the examples I see, s.page is set as a function of time, but I need to show all frames, regardless of time. So I was thinking of doing something along these lines:
def showOtherFrames(self, pars, ackClient):
direction, ack = pars[0], pars[2]
self.sequence.page = range(1, len(self.sequence.pages)) if (direction == 0) else range(len(self.sequence.pages)-2, -1, -1)
But this won't work. Alternatively I thought of defining a function that takes t as argument, but ignores it and uses instead a counter kept in a global variable, but I'd like to understand what is the proper way of doing this.

When you make s.page a dynamic property, the function assigned to it must take one argument (t), but you can still just use any variables in the space when defining that function, and not even use the time argument at all.
So, for example, you could do something as simple as:
w = Shady.World(...)
s = w.Stimulus(...)
s.page = lambda t: w.framesCompleted
which will set the page property to the current frame count. That sounds like it could be useful for your problem.

Your global-variable idea is one perfectly valid way to do this. Or, since it looks like you're defining things as methods of an instance of your own custom class, you could use instance methods as your animation callbacks and/or dynamic property values—then, instead of truly global variables, it makes sense to use attributes of self:
import Shady
class Foo(object):
def __init__(self, stimSources):
self.wind = Shady.World()
self.stim = self.wind.Stimulus(stimSources, multipage=True)
self.stim.page = self.determinePage # dynamic property assignment
def determinePage(self, t):
# Your logic here.
# Ignore `t` if you think that's appropriate.
# Use `self.wind.framesCompleted` if it's helpful.
# And/or use custom attributes of `self` if that's
# helpful (or, similarly, global variables if you must).
# But since this is called once per frame (whenever the
# frame happens to be) it could be as simple as:
return self.stim.page + 1
# ...which is indefinitely sustainable since page lookup
# will wrap around to the number of available pages.
# Let's demo this idea:
foo = Foo(Shady.PackagePath('examples/media/alien1/*.png'))
Shady.AutoFinish(foo.wind)
Equivalent to that simple example, you could have the statement self.stim.page += 1 (and whatever other logic) inside a more-general animation callback.
Another useful tool for frame-by-frame animation is support for python's generator functions, i.e. functions that include a yield statement. Worked examples are included in python -m Shady demo precision and python -m Shady demo dithering.
It can also be done in a StateMachine which is always my preferred answer to such things:
import Shady
class Foo(object):
def __init__(self, stimSources):
self.wind = Shady.World()
self.stim = self.wind.Stimulus(stimSources, multipage=True)
foo = Foo(Shady.PackagePath('examples/media/alien1/*.png'))
sm = Shady.StateMachine()
#sm.AddState
class PresentTenFrames(sm.State):
def ongoing(self): # called on every frame while the state is active
foo.stim.page += 1
if foo.stim.page > 9:
self.ChangeState()
#sm.AddState
class SelfDestruct(sm.State):
onset = foo.wind.Close
foo.wind.SetAnimationCallback(sm)
Shady.AutoFinish(foo.wind)

Remove a specific QWidget from a QSplitter

I want to remove a specific Qwidget from a QSplitter (or theQSplitterwith it is the best choice i thing) after i create 2-3 of them.
To do this, i thing that i need to get the index of every widget that i create.
This is my code:
class Windows(self):
list1 = [widget1, widget2, widget3]
counter = 0
def __init__(self):
#A lot of stuff in here
self.splitter = QSplitter(Qt.Vertical)
self.spliiter_2 = QSplitter(Qt.Horizontal)
self.splitter_2.addwidget(self.splitter)
def addWidget(self):
if counter == 1:
self.splitter.addWidget(Windows.list1[0])
counter += 1
if counter == 2:
counter += 1
self.splitter.addWidget(Windows.list1[1])
if counter == 3:
self.splitter.addWidget(Windows.list1[2])
counter += 1
def deleteWidget(self):
??????????????
As you can see above, i create a QSplitter in the class Windows, and then i create another one (self.splitter_2) where i put the first one.
Every time that i press a combination of keys, i call the addWidget method, and it adds a widget (that depends of the variable counter) from the list1.
If i want to delete the 2nd widget(for example), how can i do it, without deleting the first widget?. I thing that i need the index, but i do not know how to get it.
I have created a button that calls the deleteWidgetmethod, by the way.
I read about the hide() form, but i do not know how to specified it. But, i would rather delete it completely.
Hope you can help me.

Your deleteWidget() function could look like this:
def deleteWidget(self, index):
delete_me = self.splitter.widget(index)
delete_me.hide()
delete_me.deleteLater()
We need hide() because according to the documentation
When you hide() a child, its space will be distributed among the other
children.