Python Qt5 : submenu example.

Using my old example I will create a submenu with PyQt5.
First, you need to know the submenu works like the menu.
Let's see the result:

The source code is very simple:

# -*- coding: utf-8 -*-
"""
@author: catafest
"""
import sys
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication, QDesktopWidget, QMenu
from PyQt5.QtGui import QIcon

class Example(QMainWindow):
    #init the example class to draw the window application    
    def __init__(self):
        super().__init__()    
        self.initUI()
    #create the def center to select the center of the screen         
    def center(self):
        # geometry of the main window
        qr = self.frameGeometry()
        # center point of screen
        cp = QDesktopWidget().availableGeometry().center()
        # move rectangle's center point to screen's center point
        qr.moveCenter(cp)
        # top left of rectangle becomes top left of window centering it
        self.move(qr.topLeft())
    #create the init UI to draw the application
    def initUI(self):               
        #create the action for the exit application with shortcut and icon
        #you can add new action for File menu and any actions you need
        exitAct = QAction(QIcon('exit.png'), '&Exit', self)        
        exitAct.setShortcut('Ctrl+Q')
        exitAct.setStatusTip('Exit application')
        exitAct.triggered.connect(qApp.quit)
        #create the status bar for menu 
        self.statusBar()
        #create the menu with the text File , add the exit action 
        #you can add many items on menu with actions for each item
        menubar = self.menuBar()
        fileMenu = menubar.addMenu('&File')
        fileMenu.addAction(exitAct)
        
        # add submenu to menu 
        submenu = QMenu('Submenu',self)

        # some dummy actions
        submenu.addAction('Submenu 1')
        submenu.addAction('Submenu 2')
           
        # add to the top menu
        menubar.addMenu(submenu)
        #resize the window application 
        self.resize(640, 480)
        #draw on center of the screen 
        self.center()
        #add title on windows application 
        self.setWindowTitle('Simple menu')
        #show the application
        self.show()
        #close the UI class
        
if __name__ == '__main__':
    #create the application 
    app = QApplication(sys.argv)
    #use the UI with new  class
    ex = Example()
    #run the UI 
    sys.exit(app.exec_())

Using Google Classroom API with python.

Today I read and test Google API with the Python programming language.
You can find a good example here.
The example shows how to read with Google Classroom API, v1.
This example can be used as a default example if you want to use googlescopes.
The Google documentation tells us:
This document lists the OAuth 2.0 scopes that you might need to request to access Google APIs, depending on the level of access you need. Sensitive scopes require review by Google and have a sensitive indicator on the Google Cloud Platform (GCP) Console's OAuth consent screen configuration page. Many scopes overlap, so it's best to use a scope that isn't sensitive. For information about each method's scope requirements, see the individual API documentation.
The script use credentials.json file created by the Google project in the folder with the python script.
The script creates automatically when the authorization flow completes a token.json file.
The control of the project can be used with the Google Cloud Console.
The result of the example script can be seen in the next image:

Python Qt5 : setStyleSheet example.

Today I will show you how to style the PyQt5 widgets and create a good looking application interface.
The main goal of this tutorial is to see where you can use the style issue.
I used just one edit and one button to have a simple example.
The result of my example is this:

The example start with a simple application with QPushButton, QLineEdit.
Is more simple to use a class for the button because we need to create a different style for each action: enterEvent or leaveEvent and so on.
You can see I used QFont to change the font from button.
This class is named Push_button and will be used like any QPushButton from default PyQt5 examples.
We can do this for any widget and change it with setStyleSheet.
Another part of the code is for QLineEdit.
This can be changed easily with setStyleSheet, first with the default of this and make other changes when you need.
The source code has an QGridLayout to help us to align the widgets.
Let's see the source code:

from PyQt5 import QtWidgets, QtGui, QtCore
from PyQt5.QtCore import pyqtSignal

font_button = QtGui.QFont()
font_button.setFamily("Corbel")
font_button.setPointSize(10)
font_button.setWeight(100)

class Push_button(QtWidgets.QPushButton):
    
    def __init__(self, parent=None):
        super(Push_button, self).__init__(parent)
        self.setMouseTracking(True)
        self.setStyleSheet("margin: 1px; padding: 10px; \
      background-color: \
                           rgba(255,255,0,255); \
                           color: rgba(0,0,0,255); \
                           border-style: solid; \
                           border-radius: 4px; border-width: 3px; \
                           border-color: rgba(0,0,0,255);")

    def enterEvent(self, event):
        if self.isEnabled() is True:
            self.setStyleSheet("margin: 10px; padding: 10px; \
          background-color: \
                               rgba(255,255,0,255); \
                               color: rgba(0,0,10,255); \
                               border-style: solid; \
                               border-radius: 8px; \
                               border-width: 1px; \
                               border-color: \
                               rgba(0,0,100,255);")
        if self.isEnabled() is False:
            self.setStyleSheet("margin: 10px; padding: 10px; \
          background-color: \
                               rgba(255,255,0,255); \
                               color: rgba(0,0,10,255); \
                               border-style: solid; \
                               border-radius: 8px; \
                               border-width: 1px; \
                               border-color: \
                               rgba(0,0,100,255);")

    def leaveEvent(self, event):
        self.setStyleSheet("margin: 10px; padding: 10px; \
                           background-color: rgba(0,0,0,100); \
                           color: rgba(0,0,255,255); \
                           border-style: solid; \
                           border-radius: 8px; border-width: 1px; \
                           border-color: rgba(0,50,100,255);")


class QthreadApp(QtWidgets.QWidget):
    sig = pyqtSignal(str)
    def __init__(self, parent=None):
        QtWidgets.QWidget.__init__(self, parent)
        self.setWindowTitle("PyQt5 style application")
        self.setWindowIcon(QtGui.QIcon("icon.png"))
        self.setMinimumWidth(resolution.width() / 3)
        self.setMinimumHeight(resolution.height() / 2)
        self.setStyleSheet("QWidget { \
                           background-color: rgba(0,0,100,250);} \
                           QScrollBar:horizontal {width: 1px; \
                           height: 1px; \
                           background-color: rgba(0,100,255,0);} \
                           QScrollBar:vertical {width: 1px; \
                           height: 10px; \
                           background-color: rgba(0,41,59,255);}")
        self.linef = QtWidgets.QLineEdit(self)
        self.linef.setPlaceholderText("Input text ...")
        self.linef.setStyleSheet("margin: 10px; padding: 10px; \
                                 background-color: \
                                 rgba(0,0,0,255);\
                                 color: rgba(255,0,0,255); \
                                 border-style: solid; \
                                 border-radius: 15px; \
                                 border-width: 1px; \
                                 border-color: \
                                 rgba(255,255,255,255);")
        self.my_button = Push_button(self)
        self.my_button.setText("Blue")
        self.my_button.setFixedWidth(72)
        self.my_button.setFont(font_button)
        self.my_grid = QtWidgets.QGridLayout()
        self.my_grid.addWidget(self.linef, 0, 0, 1, 220)
        self.my_grid.addWidget(self.my_button, 0, 220, 1, 1)
        self.my_grid.setContentsMargins(8, 8, 8, 8)
        self.setLayout(self.my_grid)

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    desktop = QtWidgets.QApplication.desktop()
    resolution = desktop.availableGeometry()
    myapp = QthreadApp()
    myapp.setWindowOpacity(0.95)
    myapp.show()
    myapp.move(resolution.center() - myapp.rect().center())
    sys.exit(app.exec_())
else:
    desktop = QtWidgets.QApplication.desktop()
    resolution = desktop.availableGeometry()

Python Qt5 : QCalendarWidget example.

This tutorial is about QCalendarWidget.
Use a default application and add this widget.
You can change and get the date from the widget calendar like any widget.
The result of this source code is this result:

This is the source code for QCalendarWidget example:

import sys
from PyQt5 import *
from PyQt5.QtWidgets import QApplication, QCalendarWidget, QWidget, QLabel
from PyQt5.QtCore import *
from PyQt5.QtGui import *

class Example(QWidget):
   def __init__(self):
      super(Example, self).__init__()
      self.initUI()
   def initUI(self):
      my_calendar = QCalendarWidget(self)
      my_calendar.setGridVisible(True)
      my_calendar.move(10, 20)
      my_calendar.clicked[QDate].connect(self.show_date)
      self.my_label = QLabel(self)
      date = my_calendar.selectedDate()
      self.my_label.setText(date.toString())
      self.my_label.move(10, 220)
      self.setGeometry(100,100,320,270)
      self.setWindowTitle('Calendar')
      self.show()
   def show_date(self, date):
      self.my_label.setText(date.toString())

def main():
   app = QApplication(sys.argv)
   ex = Example()
   sys.exit(app.exec_())
if __name__ == '__main__':
   main()

Python Qt5 : QTabWidget example.

Today I test the QTabWidget with an simple example.
The source code uses the QTabWidget and create two Tab: FirstTab and TabTwo.
I add for each tab two labels: tab_one_label_one, tab_one_label_two,tab_two_label_one and tab_two_label_two.
For layouts, I used: vboxLayout with first_layout and second_layout.
The result of my running code is this:

The rest of the source code is simple:

import sys
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QDialog, QApplication, QWidget
from PyQt5.QtWidgets import QVBoxLayout, QTabWidget, QLabel

class TabDialog(QDialog):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("Tab Widget Application")
        self.setWindowIcon(QIcon("icon.png"))

        tabwidget = QTabWidget()
        tabwidget.addTab(FirstTab(), "First Tab")
        tabwidget.addTab(TabTwo(), "Second Tab")

        vboxLayout = QVBoxLayout()
        vboxLayout.addWidget(tabwidget)

        self.setLayout(vboxLayout)

class FirstTab(QWidget):
    def __init__(self):
        super().__init__()
        tab_one_label_one = QLabel("tab_one_label_one")
        tab_one_label_two = QLabel("tab_one_label_two")
        
        first_layout = QVBoxLayout()
        first_layout.addWidget(tab_one_label_one)
        first_layout.addWidget(tab_one_label_two)
        self.setLayout(first_layout)

class TabTwo(QWidget):
    def __init__(self):
        super().__init__()
        tab_two_label_one = QLabel("tab_two_label_one")
        tab_two_label_two = QLabel("tab_two_label_two")
        
        second_layout = QVBoxLayout()
        second_layout.addWidget(tab_two_label_one)
        second_layout.addWidget(tab_two_label_two)
        self.setLayout(second_layout)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    tabdialog = TabDialog()
    tabdialog.show()
    app.exec()

Python Qt5 : default icons with QStyle.

This is a simple example of QStyle.
Using the QStyle can solve more issues above this example.
The QStyle can solve more problems than this example.
You can change everything in PyQt5 and Qt.
The QStyle class is an abstract base class that encapsulates the look and feel of a GUI, read here.
This is the result of a source code I used to show you how can use default icons from PyQt5.

See this source code:

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class Widget(QWidget):
  
    def __init__(self, parent= None):
        super(Widget, self).__init__()
        icons = [
'SP_TitleBarMinButton', 
'SP_TitleBarMenuButton', 
'SP_TitleBarMaxButton', 
'SP_TitleBarCloseButton', 
'SP_TitleBarNormalButton', 
'SP_TitleBarShadeButton', 
'SP_TitleBarUnshadeButton', 
'SP_TitleBarContextHelpButton', 
'SP_MessageBoxInformation', 
'SP_MessageBoxWarning', 
'SP_MessageBoxCritical', 
'SP_MessageBoxQuestion', 
'SP_DesktopIcon', 
'SP_TrashIcon', 
'SP_ComputerIcon', 
'SP_DriveFDIcon', 
'SP_DriveHDIcon', 
'SP_DriveCDIcon', 
'SP_DriveDVDIcon', 
'SP_DriveNetIcon', 
'SP_DirHomeIcon', 
'SP_DirOpenIcon', 
'SP_DirClosedIcon', 
'SP_DirIcon', 
'SP_DirLinkIcon', 
'SP_FileIcon', 
'SP_FileLinkIcon', 
'SP_FileDialogStart', 
'SP_FileDialogEnd', 
'SP_FileDialogToParent', 
'SP_FileDialogNewFolder', 
'SP_FileDialogDetailedView', 
'SP_FileDialogInfoView', 
'SP_FileDialogContentsView', 
'SP_FileDialogListView', 
'SP_FileDialogBack', 
'SP_DockWidgetCloseButton', 
'SP_ToolBarHorizontalExtensionButton', 
'SP_ToolBarVerticalExtensionButton', 
'SP_DialogOkButton', 
'SP_DialogCancelButton', 
'SP_DialogHelpButton', 
'SP_DialogOpenButton', 
'SP_DialogSaveButton', 
'SP_DialogCloseButton', 
'SP_DialogApplyButton', 
'SP_DialogResetButton', 
'SP_DialogDiscardButton', 
'SP_DialogYesButton', 
'SP_DialogNoButton', 
'SP_ArrowUp',  
'SP_ArrowDown', 
'SP_ArrowLeft', 
'SP_ArrowRight', 
'SP_ArrowBack', 
'SP_ArrowForward', 
'SP_CommandLink', 
'SP_VistaShield', 
'SP_BrowserReload', 
'SP_BrowserStop', 
'SP_MediaPlay', 
'SP_MediaStop', 
'SP_MediaPause', 
'SP_MediaSkipForward',
'SP_MediaSkipBackward', 
'SP_MediaSeekForward',
'SP_MediaSeekBackward', 
'SP_MediaVolume', 
'SP_MediaVolumeMuted', 
'SP_CustomBase'
            ]
        Col_size = 6
         
        layout = QGridLayout()
 
        count = 0
        for i in icons:
            select_button = QPushButton(i)
            select_button.setIcon(self.style().standardIcon(getattr(QStyle, i)))
 
            layout.addWidget(select_button, count / Col_size, count % Col_size)
            count += 1
             
        self.setLayout(layout)
         
if __name__ == '__main__':
    app = QApplication(sys.argv)
             
    dialog = Widget()
    dialog.show()
             
    app.exec_()

Python Qt5 : QFileDialog and QTextEdit example.

This tutorial is about QFileDialog and how to use it.
First you need to create a default PyQ5 application and add your method is called by my_OpenDialog.
This will be connected to one button.
My application uses the QTextEdit to show HTML and text files.
If you try to see another file this will open badly.
I set the completeSuffix just for HTML and text.
As you know this returns the complete suffix (extension) of the file.
The content of this file is put into QTextEdit widget create and named editor_text.
This is result of using QFileDialog with python:

This is the source code with the QFileDialog example:

import sys, os
from PyQt5 import QtCore, QtWidgets

class Window(QtWidgets.QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.setWindowTitle('Text document')
        self.editor_text = QtWidgets.QTextEdit(self)

        self.button_OpenDialog = QtWidgets.QPushButton('Open', self)
        self.button_OpenDialog.clicked.connect(self.my_OpenDialog)

        layout = QtWidgets.QGridLayout(self)
        layout.addWidget(self.editor_text, 0, 0, 1, 1)
        layout.addWidget(self.button_OpenDialog, 1, 0)
        #self.handleTextChanged()

    def my_OpenDialog(self):
        path = QtWidgets.QFileDialog.getOpenFileName(
            self, 'Open file', '',
            'HTML files (*.html);;Text files (*.txt)')[0]
        if path:
            file = QtCore.QFile(path)
            if file.open(QtCore.QIODevice.ReadOnly):
                stream = QtCore.QTextStream(file)
                text = stream.readAll()
                info = QtCore.QFileInfo(path)
                if info.completeSuffix() == 'html':
                    self.editor_text.setHtml(text)
                else:
                    self.editor_text.setPlainText(text)
                file.close()

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = Window()
    window.resize(640, 480)
    window.show()
    sys.exit(app.exec_())

Python Qt5 : QLCDNumber and QDial example.

This tutorial uses a simple example of QLCDNumber and QDial.
The steps start with create the QWidget with the QLCDNumber and QDial.
You need to set geometry for both and connect the dial with valueChanged.
Finally you need to use show to see the QWidget.
The result is show into the next screenshot:

Let see the source code:

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QWidget, QLCDNumber, QDial, QApplication)

class QLCDNumber_QDial(QWidget):
    def __init__(self):
        super().__init__()
        self.initUi()

    def initUi(self):
        the_lcd = QLCDNumber(self)
        the_dial = QDial(self)

        self.setGeometry(150, 100, 220, 100)
        self.setWindowTitle('QLCDNumber')

        the_lcd.setGeometry(10,10,70,70)
        the_dial.setGeometry(140,10,70,70)

        the_dial.valueChanged.connect(the_lcd.display)

        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    run = QLCDNumber_QDial() 
    sys.exit(app.exec_())

Python Qt5 : QColorDialog example.

Today I will show you how to use the QColorDialog and clipboard with PyQt5.
You can read documentation from the official website.
This example used a tray icon with actions for each type of code color.
The code of color is put into clipboard area and print on the shell.
I use two ways to get the code of color:

• parse the result of currentColor depends by type of color codel;
• get the code of color by a special function from QColorDialog;

To select the color I want to use is need to use the QColorDialog:

Let's see the source code:

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

# create the application
app = QApplication([])
app.setQuitOnLastWindowClosed(False)

# get the icon file
icon = QIcon("icon.png")

# create clipboard
clipboard = QApplication.clipboard()
# create dialog color
dialog = QColorDialog()

# create functions to get parsing color
def get_color_hex():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText(color.name())
        print(clipboard.text())

def get_color_rgb():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("rgb(%d, %d, %d)" % (
            color.red(), color.green(), color.blue()
        ))
        print(clipboard.text())

def get_color_hsv():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("hsv(%d, %d, %d)" % (
            color.hue(), color.saturation(), color.value()
        ))
        print(clipboard.text())
# create function to use getCmyk 
def get_color_getCmyk():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("Cmyk(%d, %d, %d, %d, %d)" % (
            color.getCmyk()
        ))
        print(clipboard.text())


# create the tray icon application
tray = QSystemTrayIcon()
tray.setIcon(icon)
tray.setVisible(True)

# create the menu and add actions
menu = QMenu()
action1 = QAction("Hex")
action1.triggered.connect(get_color_hex)
menu.addAction(action1)

action2 = QAction("RGB")
action2.triggered.connect(get_color_rgb)
menu.addAction(action2)

action3 = QAction("HSV")
action3.triggered.connect(get_color_hsv)
menu.addAction(action3)

action4 = QAction("Cmyk")
action4.triggered.connect(get_color_getCmyk)
menu.addAction(action4)

action5 =QAction("Exit")
action5.triggered.connect(exit)
menu.addAction(action5)

# add the menu to the tray icon application
tray.setContextMenu(menu)

app.exec_()

Python Qt5 : tray icon example.

This tutorial is about another tray icon application type.
The base application is the same like any application with some changes with this steps:
- QSystemTrayIcon this will start to create the application like an tray icon application;
- create one menu to show if you use the right click of mouse;
- add a menu with action items;
- add the exit action to close the tray icon application;
- you can use the action item from menu to print a message
Let's see the source code:

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
# create the application
app = QApplication([])
app.setQuitOnLastWindowClosed(False)

# create the icon
icon = QIcon("icon.png")

# create the tray icon 
tray = QSystemTrayIcon()
tray.setIcon(icon)
tray.setVisible(True)

# this will print a message 
def print_msg():
 print("This action is triggered connect!")

# create the menu for tray icon
menu = QMenu()

# add one item to menu 
action = QAction("This is menu item")
menu.addAction(action)
action.triggered.connect(print_msg)

# add exit item to menu 
exitAction = QAction("&Exit")
menu.addAction(exitAction)
exitAction.triggered.connect(exit)

# add the menu to the tray
tray.setContextMenu(menu)

# start application execution 
app.exec_()

This is result of the running source code:

Python Qt5 : QtSql with QtOpenGL example.

Today I will show you how to deal with QtOpenGL.
Let's make a test to see what is this:

>>> import PyQt5
>>> from PyQt5.QtOpenGL import *
>>> dir(PyQt5.QtOpenGL)
['QGL', 'QGLContext', 'QGLFormat', 'QGLWidget', '__doc__', '__file__', '__loader
__', '__name__', '__package__', '__spec__']

The QtOpenGL is used to take an OpenGL content and show into the PyQt5 application.
You need to kknow how to use OpenGL API.
You can see the result of this example:

This is the source code for my example:

import sys
import math

from PyQt5.QtCore import Qt
from PyQt5.QtGui import QColor
from PyQt5.QtWidgets import QApplication, QMessageBox
from PyQt5.QtOpenGL import QGL, QGLFormat, QGLWidget

try:
    from OpenGL import GL
except ImportError:
    app = QApplication(sys.argv)
    QMessageBox.critical(None, "OpenGL samplebuffers",
            "PyOpenGL must be installed to run this example.")
    sys.exit(1)

# use to create OpenGL content 
class GLWidget(QGLWidget):
    GL_MULTISAMPLE = 0x809D
    # rotation to 0
    rot = 0.0

    def __init__(self, parent):
        super(GLWidget, self).__init__(QGLFormat(QGL.SampleBuffers), parent)
        self.list_ = []
        self.startTimer(40)
        self.setWindowTitle("OpenGL with sample buffers")

    def initializeGL(self):
        GL.glMatrixMode(GL.GL_PROJECTION)
        GL.glLoadIdentity()
        GL.glOrtho( -.5, .5, .5, -.5, -1000, 1000)
        GL.glMatrixMode(GL.GL_MODELVIEW)
        GL.glLoadIdentity()
        GL.glClearColor(1.0, 1.0, 1.0, 1.0)

        self.makeObject()

    def resizeGL(self, w, h):
        GL.glViewport(0, 0, w, h)

    def paintGL(self):
        GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)

        GL.glMatrixMode(GL.GL_MODELVIEW)
        GL.glPushMatrix()
        GL.glEnable(GLWidget.GL_MULTISAMPLE)
        GL.glTranslatef( -0.25, -0.10, 0.0)
        GL.glScalef(0.75, 1.15, 0.0)
        GL.glRotatef(GLWidget.rot, 0.0, 0.0, 1.0)
        GL.glCallList(self.list_)
        GL.glPopMatrix()

        GL.glPushMatrix()
        GL.glDisable(GLWidget.GL_MULTISAMPLE)
        GL.glTranslatef(0.25, -0.10, 0.0)
        GL.glScalef(0.75, 1.15, 0.0)
        GL.glRotatef(GLWidget.rot, 0.0, 0.0, 1.0)
        GL.glCallList(self.list_)
        GL.glPopMatrix()

        GLWidget.rot += 0.2

        self.qglColor(Qt.black)
        self.renderText(-0.35, 0.4, 0.0, "Multisampling enabled")
        self.renderText(0.15, 0.4, 0.0, "Multisampling disabled")

    def timerEvent(self, event):
        self.update()
    # create one object 
    def makeObject(self):
        x1 = +0.05
        y1 = +0.25
        x2 = +0.15
        y2 = +0.21
        x3 = -0.25
        y3 = +0.2
        x4 = -0.1  
        y4 = +0.2
        x5 = +0.25 
        y5 = -0.05

        self.list_ = GL.glGenLists(1)
        GL.glNewList(self.list_, GL.GL_COMPILE)
        
        self.qglColor(Qt.blue)
        self.geometry(GL.GL_POLYGON, x1, y1, x2, y2, x3, y3, x4, y4, x5, y5)
        
        GL.glEndList()
    # create geometry of object depend of render - GL_POLYGON
    # used five points 
    def geometry(self, primitive, x1, y1, x2, y2, x3, y3, x4, y4, x5, y5):
        GL.glBegin(primitive)

        GL.glVertex2d(x1, y1)
        GL.glVertex2d(x2, y2)
        GL.glVertex2d(x3, y3)
        GL.glVertex2d(x4, y4)
        GL.glVertex2d(x5, y5)

        GL.glEnd()
# start the application 
if __name__ == '__main__':

    app = QApplication(sys.argv)

    my_format = QGLFormat.defaultFormat()
    my_format.setSampleBuffers(True)
    QGLFormat.setDefaultFormat(my_format)

    if not QGLFormat.hasOpenGL():
        QMessageBox.information(None, "OpenGL using samplebuffers",
                "This system does not support OpenGL.")
        sys.exit(0)

    widget = GLWidget(None)

    if not widget.format().sampleBuffers():
        QMessageBox.information(None, "OpenGL using samplebuffers",
                "This system does not have sample buffer support.")
        sys.exit(0)

    widget.resize(640, 480)
    widget.show()

    sys.exit(app.exec_())

Python Qt5 : QtSql with QSQLITE example.

Today I will show you how to deal with QtSql and QSQLITE and show a table into an MDI (Multiple Document Interface) application.
First I create tree scripts named:

• PyQt5_connection.py - create a memory database and add value into table;
• PyQt5_view.py - create a model for the table;
• PyQt5_show.py - show the MDI application with the model table database;

The source code is commented and is simple to understand.
Let's see this python scripts:
First is PyQt5_connection.py:

from PyQt5 import QtWidgets, QtSql
from PyQt5.QtSql import *

def createConnection():
    db = QtSql.QSqlDatabase.addDatabase("QSQLITE")
    db.setDatabaseName(":memory:")
    if not db.open():
        QtWidgets.QMessageBox.critical(None, "Cannot open memory database",
                             "Unable to establish a database connection.\n\n"
                             "Click Cancel to exit.", QtWidgets.QMessageBox.Cancel)
        return False
    query = QtSql.QSqlQuery()
    #print (os.listdir("."))
    query.exec("DROP TABLE IF EXISTS Websites")
    query.exec("CREATE TABLE Websites (ID INTEGER PRIMARY KEY NOT NULL, " +     "website VARCHAR(20))")
    query.exec("INSERT INTO Websites (website) VALUES('python-catalin.blogspot.com')")
    query.exec("INSERT INTO Websites (website) VALUES('catalin-festila.blogspot.com')")
    query.exec("INSERT INTO Websites (website) VALUES('free-tutorials.org')")
    query.exec("INSERT INTO Websites (website) VALUES('graphic-3d.blogspot.com')")
    query.exec("INSERT INTO Websites (website) VALUES('pygame-catalin.blogspot.com')")
    return True

The next is the PyQt5_view.py python script with the model of the table from database:

from PyQt5 import QtWidgets, QtSql

from PyQt5 import QtWidgets, QtSql

class WebsitesWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(WebsitesWidget, self).__init__(parent)
 # this layout_box can be used if you need more widgets 
 # I used just one named WebsitesWidget
        layout_box = QtWidgets.QVBoxLayout(self)
 #
        my_view = QtWidgets.QTableView()
 # put viwe in layout_box area
        layout_box.addWidget(my_view)
 # create a table model
        my_model = QtSql.QSqlTableModel(self)
        my_model.setTable("Websites")
        my_model.select()
 #show the view with model  
        my_view.setModel(my_model)
        my_view.setItemDelegate(QtSql.QSqlRelationalDelegate(my_view))

The last python script named PyQt5_show.py will create the MDI application and will show databese table:

from PyQt5 import QtWidgets, QtSql
from PyQt5_connection import createConnection
# this will import any classes from PyQt5_view script
from PyQt5_view import WebsitesWidget

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.MDI = QtWidgets.QMdiArea()
        self.setCentralWidget(self.MDI)

        SubWindow1 = QtWidgets.QMdiSubWindow()
        SubWindow1.setWidget(WebsitesWidget())
        self.MDI.addSubWindow(SubWindow1)
        SubWindow1.show()
 # you can add more widgest 
        #SubWindow2 = QtWidgets.QMdiSubWindow()

if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    if not createConnection():
        print("not connect")
        sys.exit(-1)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

This is the result of the running PyQt5_show.py python script:

Python Qt5 : QtWebEngine example.

The QtWebEngine is the new web rendering engine that is planned to replace QtWebKit in Qt.
The official website tells us:
QtWebEngineWidgets or QtWebEngine libraries, depending on application type
Let's test this web rendering engine with a simple source code:

import sys
from PyQt5.QtCore import *
from PyQt5.QtWidgets import QApplication
# use the QtWebEngineWidgets
from PyQt5.QtWebEngineWidgets import *
# start my_app
my_app = QApplication(sys.argv)
# open webpage
my_web = QWebEngineView()
my_web.load(QUrl("http://free-tutorials.org"))
my_web.show()
# sys exit function
sys.exit(my_app.exec_())

The output of this running source code.