Why the paintEvent is called repetitively in PySide6

2022-05-04 09:52 Udesh Ranjan imported from Stackoverflow

In the below small piece of code why does the paintEvent method is called repetitively?

The print(f'paint {datetime.now()}') line confirms that the paintEvent method is called continuously.

#!/usr/bin/env python3.10

import sys
import random
from datetime import datetime

from PySide6.QtWidgets import (QApplication, QMainWindow, 
        QLabel, QWidget)
from PySide6.QtCore import (Qt, QRect, QPoint)
from PySide6.QtGui import (QColor, QPen, QBrush, QPainter,
        QPixmap)


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.label = QLabel()
        self.pixmap = QPixmap(500, 500)
        self.pixmap.fill(Qt.white)
        self.label.setPixmap(self.pixmap)
        self.setCentralWidget(self.label)

    
    def paintEvent(self, event):
        print(f'paint {datetime.now()}')
        self.pixmap = self.label.pixmap()

        painter = QPainter(self.pixmap)
        pen= QPen()
        pen.setWidth(3)
        painter.setPen(pen)
        painter.drawRect(100, 100, 300, 300)
        self.label.setPixmap(self.pixmap)

        painter.end()

if __name__ == "__main__":
    app = QApplication(sys.argv)

    mainWindow = MainWindow()
    mainWindow.show()

    app.exec()

How to prevent the paintEvent method unnecessary calls?

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Python File Tagging System does not retrieve nested dictionaries in dictionary

I am building a file tagging system using Python. The idea is simple. Given a directory of files (and files within subdirectories), I want to filter them out using a filter input and tag those files with a word or a phrase.

If I got the following contents in my current directory:

data/
   budget.xls
   world_building_budget.txt
a.txt
b.exe
hello_world.dat
world_builder.spec

and I execute the following command in the shell:

py -3 tag_tool.py -filter=world -tag="World-Building Tool"

My output will be:

These files were tagged with "World-Building Tool":
data/ world_building_budget.txt
hello_world.dat
world_builder.spec

My current output isn't exactly like this but basically, I am converting all files and files within subdirectories into a single dictionary like this:

def fs_tree_to_dict(path_):
    file_token = ''
    for root, dirs, files in os.walk(path_):
        tree = {d: fs_tree_to_dict(os.path.join(root, d)) for d in dirs}
        tree.update({f: file_token for f in files})
        return tree

Right now, my dictionary looks like this: key:''.

In the following function, I am turning the empty values '' into empty lists (to hold my tags):

def empty_str_to_list(d):
    for k,v in d.items():
        if v == '':
            d[k] = []
        elif isinstance(v, dict):
            empty_str_to_list(v)

When I run my entire code, this is my output:

hello_world.dat ['World-Building Tool']
world_builder.spec ['World-Building Tool']

But it does not see data/world_building_budget.txt. This is the full dictionary:

{'data': {'world_building_budget.txt': []},  
'a.txt': [],
'hello_world.dat': [], 
'b.exe': [], 
'world_builder.spec': []}

This is my full code:

import os, argparse


def fs_tree_to_dict(path_):
    file_token = ''
    for root, dirs, files in os.walk(path_):
        tree = {d: fs_tree_to_dict(os.path.join(root, d)) for d in dirs}
        tree.update({f: file_token for f in files})
        return tree


def empty_str_to_list(d):
    for k, v in d.items():
        if v == '':
            d[k] = []
        elif isinstance(v, dict):
            empty_str_to_list(v)


parser = argparse.ArgumentParser(description="Just an example", formatter_class=argparse.ArgumentDefaultsHelpFormatter)

parser.add_argument("--filter", action="store", help="keyword to filter files")
parser.add_argument("--tag", action="store", help="a tag phrase to attach to a file")
parser.add_argument("--get_tagged", action="store", help="retrieve files matching an existing tag")

args = parser.parse_args()

filter = args.filter
tag = args.tag
get_tagged = args.get_tagged
current_dir = os.getcwd()

files_dict = fs_tree_to_dict(current_dir)
empty_str_to_list(files_dict)

for k, v in files_dict.items():
    if filter in k:
        if v == []:
            v.append(tag)
            print(k, v)

        elif isinstance(v, dict):
            empty_str_to_list(v)

    if get_tagged in v:
        print(k, v)

Actaully i am working on a project and in it, it is showing no module name pip_internal plz help me for the same. I am using pycharm(conda interpreter

 File "C:\Users\pjain\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Users\pjain\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "C:\Users\pjain\AppData\Local\Programs\Python\Python310\Scripts\pip.exe\__main__.py", line 4, in <module>
  File "C:\Users\pjain\AppData\Local\Programs\Python\Python310\lib\site-packages\pip\_internal\__init__.py", line 4, in <module>
    from pip_internal.utils import _log

I am using pycharm with conda interpreter.

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I'm new to python (first of all) I have a homework to do a function about checking if an item exists in a dictionary or not.

inventory = {"apple" : 50, "orange" : 50, "pineapple" : 70, "strawberry" : 30}

def check_item():
    x = input("Enter the fruit's name: ")
    if not x.isalpha():
        print("Error! You need to type the name of the fruit")
    elif x in inventory:
        print("Fruit found:", x)
        print("Inventory available:", inventory[x],"KG")
    else:
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check_item()

I want the function to loop again only if the input written is not string. I've tried to type return Under print("Error! You need to type the name of the fruit") but didn't work. Help

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TypeError: 'float' object cannot be interpreted as an integer on linspace

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File <__array_function__ internals>:5, in linspace(*args, **kwargs)

File ~\AppData\Local\Programs\Python\Python39\lib\site-packages\numpy\core\function_base.py:120, in linspace(start, stop, num, endpoint, retstep, dtype, axis)

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         28 
       (...)
        118 
        119     """
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        121     if num < 0:
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    TypeError: 'float' object cannot be interpreted as an integer

What solution about this problem?

IndexError: list index out of range with api

all_currencies = currency_api('latest', 'currencies')  # {'eur': 'Euro', 'usd': 'United States dollar', ...}
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https://doc.qt.io/qt-5/qmake-test-function-reference.html

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Evaluates the contents of the string using qmake syntax rules and returns true. Definitions and assignments can be used in the string to modify the values of existing variables or create new definitions.

For example:

eval(TARGET = myapp) {
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}

I wondering when/why that should be used? Can't we just use TARGET = myapp directly?

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import matplotlib.pyplot as plt
import numpy as np
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def main():
    imarray = np.random.rand(100, 100) * 515
    imarray = np.clip(imarray, 0, 515)
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    pyqtgraph_example(imarray)

def plt_example(data):
    plt.imshow(data, cmap='hot')
    c = plt.colorbar()
    plt.clim(0, 200)
    plt.show(block=False)

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    win.setWindowTitle('pyqtgraph example: ImageItem')
    win.show()

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    plot = win.addPlot()
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    plot.invertY()

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    img = pg.ImageItem(data, axisOrder='row-major')
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    app.exec()

if __name__ == "__main__":
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import matplotlib.pyplot as plt

x = [1,1,2,3,3,5,7,8,9,10,
 10,11,11,13,13,15,16,17,18,18,
 18,19,20,21,21,23,24,24,25,25,
 25,25,26,26,26,27,27,27,27,27,
 29,30,30,31,33,34,34,34,35,36,
 36,37,37,38,38,39,40,41,41,42,
 43,44,45,45,46,47,48,48,49,50,
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 61,63,64,65,66,68,70,71,72,74,
 75,77,81,83,84,87,89,90,90,91
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histogram graph output

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from PySide6.__feature__ import snake_case, true_property
from PySide6.QtWidgets import QMainWindow, QWidget, QHBoxLayout, QApplication


class MainWindow(QMainWindow):
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        super().__init__()

        self.main_layout = QHBoxLayout()
        self.container = QWidget()
        self.container.set_layout(self.main_layout)


if __name__ == '__main__':
    app = QApplication([])
    main_window = MainWindow()
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I got an error message when trying to run the above code:

ModuleNotFoundError: No module named 'PySide6.__feature__'

If I break the first line into

import PySide6
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Here is my code.

from PySide6.QtCore import Qt, QSize
from PySide6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QHBoxLayout, QLabel, QPushButton


class MainWindow(QMainWindow):
    def __init__(self):
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        self.button_2 = QPushButton('Button 2')
        self.button_2.setFixedSize(QSize(70, 60))
        self.button_3 = QPushButton('Button 3')
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        self.horizontalLayout.addWidget(self.button_1)
        self.horizontalLayout.addWidget(self.button_2)
        self.horizontalLayout.addWidget(self.button_3)

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Design of progressbar (It's PNG):

Here is the result on Qt:

Code of Pic2:

import sys, os, time
from PySide6 import QtCore, QtWidgets, QtGui
from PySide6.QtWidgets import *
from PySide6.QtCore import *
from PySide6.QtGui import *

class EProgressbar(QProgressBar):
    valueChanged = QtCore.Signal(int)
    _val = 0
    def __init__(self):        
        super(EProgressbar, self).__init__(None)
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        self.setFixedHeight(40)
        self._animation = QtCore.QPropertyAnimation(self, b"_vallll", duration=600)
        self.valueChanged.connect(self.update)

    def setValue(self, value:int) -> None:
        self._animation.setStartValue(self.value())
        self._animation.setEndValue(value)
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    def value(self) -> int:
        return self._val

    def ESetValue(self, value):
        if self._val != value:
            self._val = value
            self.valueChanged.emit(value)
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    def paintEvent(self, event: QPaintEvent) -> None:
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        path = QPainterPath();path2 = QPainterPath(); path3 = QPainterPath()
        font = QFont('Helvetica', 11, weight=QFont.Bold); font.setStyleHint(QFont.Times, QFont.PreferAntialias)

        BRUSH_BASE_BACKGROUND, BRUSH_BASE_FOREGROUND, BRUSH_POLYGON, BRUSH_CORNER = QColor(247,247,250), QColor(255,152,91), QColor(255,191,153), QColor(203,203,205)


        pt.setPen(QPen(BRUSH_CORNER,1.5));pt.setBrush(BRUSH_BASE_BACKGROUND)
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        path.addRoundedRect(rect, self.r, self.r)
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        path2.addRoundedRect(QRect(2,2, self._vallll/ 100 * self.width()-4, self.height()-4), self.r, self.r)
        #path2.addRoundedRect(QRect(20,2,10, self.height()), self.r, self.r)




        pt.drawPath(path)
        pt.setBrush(BRUSH_BASE_FOREGROUND)

        pt.drawPath(path2)

        pt.setPen(Qt.NoPen)
        pt.setBrush(BRUSH_POLYGON)

        start_x = 20
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        progress_filled_width = self.value()/self.maximum()*self.width()

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        for i in range(100):
            x = start_x + (i*polygon_width) + (i*polygon_space)
            if x >= progress_filled_width or (x+ polygon_width >= progress_filled_width):
                break
            path2.addPolygon(QPolygon([
            QPoint(x, y),
            QPoint(x+polygon_width, y),
            QPoint(x+polygon_width/2, self.height()-y),
            QPoint(x-polygon_width/2, self.height()-y)]))

        pt.drawPath(path2)



        pt.setFont(font)
        pt.setPen(Qt.white)
        pt.drawText(QRect(2,2,self.width()-4,self.height()-4), Qt.AlignCenter, f"%{self.value()}")

        pt.end()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    wind = QMainWindow();wind.setStyleSheet("QMainWindow{background-color:blue}");wind.setWindowTitle("EProgressBar")
    wind.resize(221,150)
    wid = QWidget();lay = QHBoxLayout(wid);lay.setAlignment(Qt.AlignCenter)
    e = EProgressbar();e.setValue(80)
    timer = QTimer(wind)
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        import random
        e.setValue(random.randint(0,100))
    timer.timeout.connect(lamb)
    #timer.start(1000)
    #e.setGeometry(QRect(10,10,170,250))
    lay.addWidget(e)
    wind.setCentralWidget(wid)
    #e.setParent(wind)
    wind.show()
    sys.exit(app.exec())

This one looks good but when I set progressbar value to 0, result like this:

Notes:

I need to use pt.setClipPath(path2, Qt.ClipOperation.ReplaceClip) else If you look closely, the polygon in the upper right has crossed the progressbar.

So I think all drawing things must be? in the same QPainterPath? When I try all the drawing in the same path (like OnePathCode) result like this:

Related questions

Why the paintEvent is called repetitively in PySide6

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