I place a widget in Qt Creator and promote it to a PyQtGraph PlotWidget. I'd like to use a custom AxisItem with that widget. Is there any way to replace the existing axis or do I have to subclass PlotWidget?
There is not currently a way to replace an existing axis; use a subclass as you suggested.
Still there isnt a way to replace existing axis without promoting to a PlotWidget subclass as mentioned in the other answers. For someone looking for an example subclass for PlotWidget that uses x axis as DateAxisItem here it is:
from pyqtgraph import PlotWidget, DateAxisItem
class XDateTimeAxis_PlotWidget(PlotWidget):
def __init__(self, parent=None, background='default', plotItem=None, **kargs):
super(XDateTimeAxis_PlotWidget, self).__init__(parent=parent, background=background, plotItem=plotItem, axisItems = {'bottom': DateAxisItem()}, **kargs)
Related
This question already has answers here:
Equivalent to time.sleep for a PyQt application
(5 answers)
Closed 2 years ago.
im new to pyqt5,i tried to open dialog and push some text into that dialog
my dialog contain one plaintext ,progressbar and pushbutton
when i run the code its popup the dialog but not shown any thing ,after code execution completes its showing all the widgets and with text
but i need to open the dialog and i want update progress bar
My code
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import (QDialog,QPlainTextEdit,QScrollArea,QProgressBar,QPushButton)
import sys
import time
class PrograssDialog():
def ShowDialog(self,Dialogs):
try:
self.Pd=Dialogs
self.Pd.setWindowTitle("Script Excution... ")
self.Pd.resize(500,500)
self.ScrArea=QScrollArea(self.Pd)
self.ScrArea.move(0,0)
self.ScrArea.resize(500,300)
self.TextArea=QPlainTextEdit(self.Pd)
self.TextArea.move(0,0)
self.TextArea.resize(500,300)
self.TextArea.insertPlainText(str("Start : %s" % time.ctime())+"\n")
self.Prograssbar=QProgressBar(self.Pd)
self.Prograssbar.setGeometry(QtCore.QRect(0, 350, 450, 23))
self.Prograssbar.setMaximum(100)
self.Cancelbutton=QPushButton("Cancel",self.Pd)
self.Cancelbutton.setGeometry(QtCore.QRect(360, 400, 93, 28))
self.Cancelbutton.clicked.connect(self.StopExcution)
self.Pd.show()
except Exception as msg:
import sys
tb = sys.exc_info()[2]
print("Error_analysis " + str(msg)+ str(tb.tb_lineno))
def AddMessage(self,Message):
self.TextArea.insertPlainText(str(Message)+"\n")
# print("message added")
def SetPercentage(self,Number):
self.Prograssbar.setValue(Number)
# print("percent added")
def StopExcution(self):
sys.exit()
app = QApplication(sys.argv)
ui=PrograssDialog()
ui.ShowDialog(QDialog())
for i in range(100):
ui.AddMessage("Hello")
ui.SetPercentage(i)
time.sleep(0.5)
sys.exit(app.exec_())
There are various problems with your code, I'll try to address all of them.
The main reason for the issue you are facing is that no blocking functions (like time.sleep) should happen in the main Qt thread (which is the thread that shows the GUI elements and allow interactions with them); blocking functions prevent the UI to correctly draw and refresh its contents, if you want to do an operation at specific intervals, you have to use a QTimer;
You should not use a basic python object subclass for this kind of situations, especially since you're only using just one dialog; you should subclass from QDialog instead and implement
To "exit" your program you should not use sys.exit (you are already using it), but use QApplication.quit() instead; also, since you already imported sys at the beginning, there's no need to import it again in the exception;
Function and variable names should not be capitalized; while you can use any casing style you want for your own code, it's common (and highly suggested) practice to always use lowercase initials, and it's also a convention you should stick to when sharing code with others, especially on Q&A sites like StackOverflow; read more on the official Style Guide for Python Code;
Always avoid fixed geometries for children widgets: what others see on their computers will probably be very different from what you see on yours, and you might end up with an unusable interface; use layout managers instead, so that the widgets can resize themselves if required;
You added a scroll area but you never use it; since you're using the same geometry for the text area I believe that you thought you were using for that, but there's no need as the text area already is a scroll area;
Here is how the code could look like in order to achieve what you want:
import time
from PyQt5 import QtCore, QtWidgets
class ProgressDialog(QtWidgets.QDialog):
def __init__(self, parent=None):
super().__init__(parent)
layout = QtWidgets.QVBoxLayout(self)
self.textArea = QtWidgets.QPlainTextEdit()
layout.addWidget(self.textArea)
self.textArea.insertPlainText(str("Start : %s" % time.ctime())+"\n")
self.textArea.setReadOnly(True)
self.progressBar = QtWidgets.QProgressBar()
layout.addWidget(self.progressBar)
self.cancelButton = QtWidgets.QPushButton('Cancel')
layout.addWidget(self.cancelButton)
self.cancelButton.clicked.connect(QtWidgets.QApplication.quit)
self.countTimer = QtCore.QTimer()
self.countTimer.timeout.connect(self.timeout)
def startCounter(self, maximum, sleepSeconds):
self.progressBar.reset()
self.progressBar.setMaximum(maximum)
# QTimer interval is in milliseconds
self.countTimer.setInterval(sleepSeconds * 1000)
self.countTimer.start()
def timeout(self):
if self.progressBar.value() == self.progressBar.maximum():
self.countTimer.stop()
return
self.setPercentage(self.progressBar.value() + 1)
self.addMessage('Hello')
def setPercentage(self, value):
self.progressBar.setValue(value)
def addMessage(self, message):
self.textArea.insertPlainText(str(message) + '\n')
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
dialog = ProgressDialog()
dialog.show()
dialog.startCounter(100, .5)
sys.exit(app.exec_())
[updating with smaller example]
We just upgraded to PyQt 5.7 and we have one the last problem left to fix in our application. Here is a standalone example that I created from our application code. Run it and see how the ellipse gets drawn beyond the view borders. This did not occur in 5.5.1. Platform is Windows 7 64 bit (running in a VM). It looks like this:
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QGraphicsView, QGraphicsScene, QHBoxLayout, QWidget, QLabel
from PyQt5.QtWidgets import QGraphicsProxyWidget, QGraphicsObject, QGraphicsEllipseItem
from PyQt5.QtGui import QBrush
class MyGraphicsItem(QGraphicsObject):
def __init__(self):
QGraphicsObject.__init__(self)
# next line could be any type of graphics item:
rect_item = QGraphicsEllipseItem(0, 0, 100, 100, self)
# effect easier to see if paint black:
rect_item.setBrush(QBrush(Qt.SolidPattern))
label_item = QGraphicsProxyWidget(self)
# *** Next line must be there for effect to be visible, but could be any other type of widget
label_item.setWidget(QLabel('a'*30))
def paint(self, painter, option, widget=None):
return
def boundingRect(self):
return self.childrenBoundingRect()
def show_problem():
app = QApplication([])
widget = QWidget()
layout = QHBoxLayout()
widget.setLayout(layout)
view = QGraphicsView()
scene = QGraphicsScene()
view.setScene(scene)
scene.addItem(MyGraphicsItem()) # *** effect only there if more than 1 item
scene.addItem(MyGraphicsItem())
layout.addWidget(view)
widget.setGeometry(100, 100, 50, 50)
widget.show()
app.exec()
show_problem()
So Russell confirmed that this is a regression in 5.7 (i.e., problem was not present in PyQt 5.6).
I posted a C++ version of my Python example to Qt Forum. A fellow there was kind enough to fix compilation bugs and run it, and saw the bug: so this is indeed a Qt bug.
There is a bug report at bugreports.qt.io that is almost certainly the same issue. It is not resolved, but by an incredible luck, it links to a post where there is a workaround: set the opacity of proxy widget item to just below 1. In the example app of my post, I added
label_item.setOpacity(0.999999)
after setting label_item's widget. I our real app (110k PyQt code) I set the opacity of all QGraphicsProxyWidget instance and it seems to work.
This workaround seems to not have any other side effects, time will tell if there are deeper problems. But it appears to be at least be a temporary solution until the bug gets fixed in Qt. I have submitted a bug report.
I am working on a program that will allow someone to enter details in order to write a CV. I am using the Tkinter module (as extra practice) but am already stuck on the menu!
At the moment I have three different options the user can choose: Write CV, Review CV and Exit. I have created a button for each option and when the user presses the button it'll open, however the menu window remains open (there is a different subroutine for each option).
I understand that you need to do something like window.destroy(), however I'm not sure how to give a button two commands without doing something too fiddly like create more subroutines etc.?
The other option I think I'd prefer is is I could clear the menu screen?
Here is the programming I have at the moment:
def Main_Menu():
import tkinter
main_menu = tkinter.Tk()
main_menu.title("CV Writer")
main_menu.geometry("300x300")
main_menu.wm_iconbitmap('cv_icon.ico')
title = tkinter.Label(main_menu, text = "Main Menu", font=("Helvetica",25))
title.pack()
gap = tkinter.Label(main_menu, text = "")
gap.pack()
write_cv = tkinter.Button(main_menu, text = "1) Write CV", font=("Helvetica"), command=Write_CV)
write_cv.pack()
review_cv = tkinter.Button(main_menu, text = "2) Review CV", font=("Helvetica"), command=Review_CV)
review_cv.pack()
leave = tkinter.Button(main_menu, text = "3) Exit", font=("Helvetica"), command=Exit)
leave.pack()
main_menu.mainloop()
def Write_CV():
import tkinter
write_cv = tkinter.Tk()
write_cv.geometry("300x300")
write_cv.title("Write CV")
def Review_CV():
import tkinter
review_cv = tkinter.Tk()
review_cv.geometry("300x300")
review_cv.title("Review CV")
def Exit():
import tkinter
leave = tkinter.Tk()
leave.geometry("300x300")
leave.title("Exit")
Main_Menu()
Running the program should help make this question make more sense!
I am so sorry for the wordy question, but any kind of help would be appreciated! Please bear in mind I am only a GCSE student so simple language would also be so nice! Thank you!
I don't know why are you importing tkinter under each method, it's completely useless. Simply import it once at the beginning of your file with a syntax like this:
import tkinter as tk
So that you can refer to the widgets simply with the duo tk:
btn = tk.Button(None, text='I can simply refer to a widget with tk')
Apart from this, the structure of your program is really bad. In my opinion, you should not instantiate Tk inside your function Main_Menu, because it will only be visible inside it. If you want to refer to the master or root or whatever you want to call the instance of Tk, you can't, because it's a local instance, as I said above.
I usually instantiate Tk in the main function of my program, or in the following if __name__ == '__main__': construct:
if __name__ == '__main__':
master = tk.Tk() # note I am using "tk"
# create your objects or call your functions here
master.mainloop()
Your are creating an instance of Tkin each of your function, that is really a bad practice, never do that. You should only create one instance of Tk for each Tkinter application.
You should use the object-oriented paradigm or make all your widgets global to structure your application.
Except these details, you can simply call master.destroy() when you want to destroy your main window and all its children widgets, where master is the Tk instance.
In general, you have a lot of errors and bad practices. My advice is:
Read a tutorial on Python first and then on Tkinter, before
proceeding.
I want to unittest drag and drop for our widgets. At the moment, I instantiate a QDragEnterEvent, but this is discouraged with a big warning on the Qt documentation, because it relies on the Qt library internal state. In fact, I get segfaults that appear to be due to a violation of this Warning.
Given this premise, how can one test drag and drop behavior?
If using Unix we can use QTest, however to get a cross-platform solution, we can implement a solution where we circumvent Qt.
Using QTest
Although the Qt documentation for drag and drop says that it will not block the main event loop, a closer look at QDrag.exec will reveal that this is not true for Windows.
The call to QTest.mousePress causes the test to block until the mouse is physically moved by the user.
I got around this in Linux by using a timer to schedule the mouse move and release:
def testDragAndDrop(self):
QtCore.QTimer.singleShot(100, self.dropIt)
QtTest.QTest.mousePress(dragFromWidget, QtCore.Qt.LeftButton)
# check for desired behaviour after drop
assert something
def dropIt(self):
QtTest.QTest.mouseMove(dropToWidget)
QtTest.QTest.mouseRelease(dropToWidget, QtCore.Qt.LeftButton, delay=15)
For this solution, it is necessary to include a delay in the mouseRelease call, and to have called show on your widget.
Note that I have verified this works using pyqt4 and Python 2.7 on Fedora 20
Cross-Platform
You can use the mouse manipulation methods from the PyUserInput package. Put the mouse interaction in separate thread to avoid the locking up of the Qt main event loop. We can do this since we are not using Qt at all in our mouse control. Make sure that you have called show on the widgets you are dragging to/from.
from __future__ import division
import sys, time, threading
import numpy as np
from PyQt4 import QtGui, QtCore, QtTest
from pymouse import PyMouse
...
def mouseDrag(source, dest, rate=1000):
"""Simulate a mouse visible mouse drag from source to dest, rate is pixels/second"""
mouse = PyMouse()
mouse.press(*source)
# smooth move from source to dest
npoints = int(np.sqrt((dest[0]-source[0])**2 + (dest[1]-source[1])**2 ) / (rate/1000))
for i in range(npoints):
x = int(source[0] + ((dest[0]-source[0])/npoints)*i)
y = int(source[1] + ((dest[1]-source[1])/npoints)*i)
mouse.move(x,y)
time.sleep(0.001)
mouse.release(*dest)
def center(widget):
midpoint = QtCore.QPoint(widget.width()/2, widget.height()/2)
return widget.mapToGlobal(midpoint)
def testDragAndDrop(self):
# grab the center of the widgets
fromPos = center(dragFromWidget)
toPos = center(dropToWidget)
dragThread = threading.Thread(target=mouseDrag, args=((fromPos.x(),fromPos.y()), (toPos.x(), toPos.y())))
dragThread.start()
# cannot join, use non-blocking wait
while dragThread.is_alive():
QtTest.QTest.qWait(1000)
# check that the drop had the desired effect
assert dropToWidget.hasItemCount() > 0
Note I have tested this using PyQt4 and Python 2.7 on Fedora and Windows 7
Haven't tried, but if your drag & drop process is Qt internal (meaning, you're dragging from and to a Qt widget), QTest might help.
Basically by doing something along the lines:
QTest.mousePress(drag_widget, Qt.LeftButton) # simulate mouse press on whatever you want to drag
QTest.mouseMove(drop_widget) # move the mouse to the target - maybe this can be skipped
QTest.mouseRelease(drop_widget, Qt.LeftButton) # simulate mouse release where you want to drop
All functions may be supplied with further positional information (e.g. to click a list item within a widget) and with optional delays to emulate a human user.
Not a copy-pasteable answer, but maybe it serves as a starter...
If I create a QIcon with a pixmap as in the following code snippet:
from PyQt5 import QtGui
icon = QtGui.QIcon(':/images/view-refresh.png')
How do I tell if the icon doesn't have a valid pixmap, e.g. because ':/images/view-refresh.png' wasn't found?
My solution is to wrap the QIcon constructor in a factory function that creates an explicit QPixmap, which is probed to see if it is valid:
def create_icon(filename):
pixmap = QtGui.QPixmap(filename)
if pixmap.isNull():
raise ValueError('No icon with filename \'{}\' found'.format(filename))
return QtGui.QIcon(pixmap)
icon = create_icon(':/images/view-refresh.png')
Note that there is also a QIcon.isNull method, but according to the documentation it can be false even if the pixmap is invalid.
The documentation for Icon.isNull() specifically says it returns false only if it has neither a pixmap nor a filename.
Looking through the list of member functions, availableSizes() looks like a better candidate. Ive tested this.
So good test to see if an icon is valid is len(icon.availableSizes())>0.