Develop Reference

Detect Slider move

I want to be able to detect if the slider has moved to a new position and then do some actions in another function called sl. Here is my code:
import sys
from PyQt5 import QtWidgets
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QLabel, QLineEdit, QScrollBar, QMainWindow, QMenu, QWidget, QGridLayout, \
QMessageBox, QListWidget, QPlainTextEdit, QTableWidget, QTableWidgetItem, QHeaderView
from PyQt5.QtWidgets import QMenuBar, QHBoxLayout, QVBoxLayout, QSlider, QPushButton, QDial, QBoxLayout, QSpacerItem
from PyQt5.QtGui import QFont, QColor, QPixmap, QResizeEvent, QPen
import PyQt5.QtGui as QtGui
import PyQt5.QtCore as QtCore
class ControlWidget(QWidget):
def __init__(self):
QWidget.__init__(self)
self.layout = QVBoxLayout()
self.layout.setContentsMargins(10, 10, 10, 10)
widget3 = QLabel("Manual")
big_font = QFont('Arial')
big_font.setPointSize(15)
widget3.setFont(big_font)
self.layout.addWidget(widget3, stretch=1)
widget2 = ManualWidget()
self.layout.addWidget(widget2, stretch=4)
self.setLayout(self.layout)
class ManualWidget(QWidget):
def __init__(self):
QWidget.__init__(self)
self.layout = QHBoxLayout()
right_widget = QWidget()
right_layout = QVBoxLayout()
right_top_widget = QWidget()
self.sld1 = self.slider('V1:', 0, 100)
right_top_layout = QVBoxLayout()
right_top_layout.setContentsMargins(0, 0, 0, 0)
right_top_layout.addWidget(self.sld1, stretch=1)
right_top_widget.setLayout(right_top_layout)
right_layout.addWidget(right_top_widget)
right_widget.setLayout(right_layout)
self.layout.addWidget(right_widget, stretch=1)
self.setLayout(self.layout)
self.layout.addWidget(self.name)
self.layout.addWidget(self.label)
self.layout.addWidget(self.slider)
print(self.sl())
def slider(self, name, low, high, step=10):
self.name = QLabel(str(name))
self.label = QLabel(str(low))
self.slider = QSlider(Qt.Horizontal, self)
self.slider.setMinimum(low)
self.slider.setMaximum(high*step)
self.slider.setValue(low)
self.slider.valueChanged.connect(self.change_value)
self.action = False
self.slider.sliderMoved.connect(self.act1)
def change_value(self):
self.set_point = (float(self.slider.value())) / 10
self.label.setText(str(self.set_point))
def act1(self):
self.action = True
return self.action
def sl(self):
if self.action == True:
x = 3
else:
x = 6
return x
class MainWidget(QWidget):
def __init__(self):
QWidget.__init__(self)
self.layout = QVBoxLayout()
self.layout.setContentsMargins(0, 0, 0, 0)
big_font = QFont('Arial')
big_font.setPointSize(10)
bottom_widget = ControlWidget()
self.layout.addWidget(bottom_widget, stretch=10)
self.setLayout(self.layout)
class Window(QMainWindow):
def __init__(self, widget):
QMainWindow.__init__(self)
self.setWindowTitle("Flow test rig")
self.menu = self.menuBar()
self.setCentralWidget(widget)
self.status = self.statusBar()
widget.parent = self
app = QApplication(sys.argv)
main_widget = MainWidget()
win = Window(main_widget)
win.show()
sys.exit(app.exec_())
I tried to detect it with the act1 function, however, self.action is always False, or when it becomes True, it does not reset to False after the first move of the slider. I appreciate it if someone would help me.

PyQt5 drawing lines that have mouse events

I have an application where I draw 2 custom widgets and then draw a line between them. I want to add a mousePressEvent to the line.
What would be the best way to do this?
I suppose I could create a QWidget of x pixel thickness and y length and then fill in the whole widget with the colour I want the line to have. Then the QWidget has the mousePressEvent that I can override. This doesn't seem like the most elegant solution and feels more like a workaround. Is there a better way?
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPaintEvent, QPainter, QPen, QFont
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QLabel
class MyWidget(QWidget):
def __init__(self, name, parent):
super().__init__(parent)
self.setAutoFillBackground(True)
self.setFixedSize(300, 100)
p = self.palette()
p.setColor(self.backgroundRole(), Qt.white)
self.setPalette(p)
lbl_name = QLabel(name, self)
lbl_name.setFont(QFont('Arial', 16))
lbl_name.move((self.width() - lbl_name.width()) / 2, self.height()/2 - lbl_name.height()/2)
class MainWindow(QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.main_widget = QWidget(self)
self.widget_1 = MyWidget("Widget 1", self)
self.widget_1.move(50, 50)
self.widget_2 = MyWidget("Widget 2", self)
self.widget_2.move(700, 600)
self.resize(1200, 800)
self.setCentralWidget(self.main_widget)
def paintEvent(self, a0: QPaintEvent) -> None:
super().paintEvent(a0)
painter = QPainter(self)
painter.setPen(QPen(Qt.red, 3, Qt.SolidLine))
widget_1_x = self.widget_1.pos().x() + self.widget_1.size().width()
widget_1_y = self.widget_1.pos().y() + self.widget_1.size().height() / 2
widget_2_x = self.widget_2.pos().x()
widget_2_y = self.widget_2.pos().y() + self.widget_2.size().height() / 2
halfway_x = widget_1_x + (widget_2_x - widget_1_x) / 2
# add mousePressEvents to these lines:
painter.drawLine(widget_1_x, widget_1_y, halfway_x, widget_1_y)
painter.drawLine(halfway_x, widget_1_y, halfway_x, widget_2_y)
painter.drawLine(halfway_x, widget_2_y, widget_2_x, widget_2_y)
if __name__ == "__main__":
app = QApplication(sys.argv)
myapp = MainWindow()
myapp.show()
sys.exit(app.exec_())
How the above code looks like when run

PyQt5 stop timer inside a widget that was added from a different class

I would like to display the current date and time on the top of multiple windows, so I created a class of this top widget. It works, however when I switch to another window, the timer keeps running on the previous window too. How can I stop the timer right before switching window, perhaps keep the same instance running on the new window?
from PyQt5 import QtCore
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QHBoxLayout, QWidget
import sys
from datetime import datetime
CurrentWindow = None
class TopBar(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.labelTime = QtWidgets.QLabel(self)
self.labelTime.setStyleSheet("background-color: rgba(0, 0, 0, 0); color: white")
background = QtWidgets.QWidget(self)
background.setStyleSheet("background-color: rgba(0, 191, 255, 0.6)")
background.setGeometry(0, 0, 480, 30)
hbox = QHBoxLayout(background)
hbox.setContentsMargins(10, 0, 10, 0)
hbox.addWidget(self.labelTime, alignment=QtCore.Qt.AlignRight)
self.timer = QtCore.QTimer(self)
self.timer.setInterval(1000)
self.timer.timeout.connect(self.displayTime)
self.timer.start()
self.displayTime()
def displayTime(self):
print(self.parent())
self.labelTime.setText(datetime.now().strftime("%Y/%m/%d %H:%M:%S"))
class Window1(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.resize(480, 320)
self.centralwidget = QtWidgets.QWidget(self)
self.setCentralWidget(self.centralwidget)
widgetTop = QtWidgets.QWidget(self.centralwidget)
widgetTop.setGeometry(0, 0, 480, 30)
layoutTop = QHBoxLayout(widgetTop)
layoutTop.addWidget(TopBar())
layoutTop.setContentsMargins(0, 0, 0, 0)
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setText('Go to Window2')
self.pushButton.clicked.connect(self.goToWindow2)
layoutCenter = QHBoxLayout(self.centralwidget)
layoutCenter.addWidget(self.pushButton, alignment=QtCore.Qt.AlignCenter)
self.show()
def goToWindow2(self):
global CurrentWindow
CurrentWindow = Window2()
self.close()
class Window2(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.resize(480, 320)
self.centralwidget = QtWidgets.QWidget(self)
self.setCentralWidget(self.centralwidget)
widgetTop = QtWidgets.QWidget(self.centralwidget)
widgetTop.setGeometry(0, 0, 480, 30)
layoutTop = QHBoxLayout(widgetTop)
layoutTop.addWidget(TopBar())
layoutTop.setContentsMargins(0, 0, 0, 0)
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setText('Go to Window1')
self.pushButton.clicked.connect(self.goToWindow1)
layoutCenter = QHBoxLayout(self.centralwidget)
layoutCenter.addWidget(self.pushButton, alignment=QtCore.Qt.AlignCenter)
self.show()
def goToWindow1(self):
global CurrentWindow
CurrentWindow = Window1()
self.close()
if __name__=='__main__':
app = QApplication(sys.argv)
ex = Window1()
sys.exit(app.exec_())

I don't think that the QTimer execution slows down the application.
But I will still show you how to stop it from another window. To do this you must access the object so you must become a member of the class, and then when you change the window you stop it with the stop method of the QTimer.
class Window1(QMainWindow):
# ...
def initUI(self):
# ...
layoutTop = QHBoxLayout(widgetTop)
self.topbar = TopBar()
layoutTop.addWidget(self.topbar)
layoutTop.setContentsMargins(0, 0, 0, 0)
# ...
def goToWindow2(self):
global CurrentWindow
self.topbar.timer.stop()
CurrentWindow = Window2()
self.close()
class Window2(QMainWindow):
# ...
def initUI(self):
# ...
layoutTop = QHBoxLayout(widgetTop)
self.topbar = TopBar()
layoutTop.addWidget(self.topbar)
layoutTop.setContentsMargins(0, 0, 0, 0)
# ...
def goToWindow1(self):
global CurrentWindow
self.topbar.timer.stop()
CurrentWindow = Window1()
self.close()
If you still consider that the cause of the error is to have several QTimer then in the following code there will only be one TopBar and they will change the widget using a QStackedWidget
from PyQt5 import QtCore
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QHBoxLayout, QWidget
import sys
from datetime import datetime
class TopBar(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.setAttribute(QtCore.Qt.WA_StyledBackground)
self.labelTime = QtWidgets.QLabel()
self.labelTime.setStyleSheet("background-color: rgba(0, 0, 0, 0); color: white")
self.setStyleSheet("background-color: rgba(0, 191, 255, 0.6)")
self.setFixedHeight(30)
hbox = QHBoxLayout(self)
hbox.setContentsMargins(10, 0, 10, 0)
hbox.addWidget(self.labelTime, alignment=QtCore.Qt.AlignRight)
self.timer = QtCore.QTimer(self)
self.timer.setInterval(1000)
self.timer.timeout.connect(self.displayTime)
self.timer.start()
self.displayTime()
def displayTime(self):
self.labelTime.setText(datetime.now().strftime("%Y/%m/%d %H:%M:%S"))
class Window(QWidget):
changeWindow = QtCore.pyqtSignal(int)
def changeTo(self, index):
def callback():
self.changeWindow.emit(index)
return callback
class Window1(Window):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.pushButton = QtWidgets.QPushButton()
self.pushButton.setText("Go to Window2")
self.pushButton.clicked.connect(self.changeTo(1))
layoutCenter = QHBoxLayout(self)
layoutCenter.addWidget(self.pushButton, alignment=QtCore.Qt.AlignCenter)
class Window2(Window):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.pushButton = QtWidgets.QPushButton()
self.pushButton.setText("Go to Window1")
self.pushButton.clicked.connect(self.changeTo(0))
layoutCenter = QHBoxLayout(self)
layoutCenter.addWidget(self.pushButton, alignment=QtCore.Qt.AlignCenter)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.initUI()
def initUI(self):
self.resize(480, 320)
self.centralwidget = QtWidgets.QWidget(self)
self.setCentralWidget(self.centralwidget)
self.topbar = TopBar()
lay = QtWidgets.QVBoxLayout(self.centralwidget)
lay.setContentsMargins(0, 0, 0, 0)
lay.addWidget(self.topbar)
stacked_widget = QtWidgets.QStackedWidget()
lay.addWidget(stacked_widget)
for w in (Window1(), Window2()):
stacked_widget.addWidget(w)
if isinstance(w, Window):
w.changeWindow.connect(stacked_widget.setCurrentIndex)
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())

How to set QGraphicsView 's background Image? [duplicate]

This question already has answers here:
Painting background on QGraphicsView using drawBackground
(1 answer)
How to enable Pan and Zoom in a QGraphicsView
(3 answers)
How to put an image in QGraphicsView's scrollbar area?
(1 answer)
Closed 3 years ago.
I'm wondering how to set QgraphicsView's background Image.
In this painter program, the background is just white color.
I want to load some image(jpg, png, .. whatever) and set it as painter's background.
and after painting it, I want to just save painting (not include background, just what i painted.)
how can i do this? please help me.
import sys
from PyQt5.QtCore import *
from PyQt5.QtCore import Qt
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtWidgets import (QApplication, QCheckBox, QGridLayout, QGroupBox,
QPushButton, QVBoxLayout, QWidget, QSlider)
QApplication.setAttribute(Qt.AA_EnableHighDpiScaling, True)
class CWidget(QWidget):
def __init__(self):
super().__init__()
# 전체 폼 박스
formbox = QHBoxLayout()
self.setLayout(formbox)
# 좌, 우 레이아웃박스
left = QVBoxLayout()
right = QVBoxLayout()
# 그룹박스2
gb = QGroupBox('펜 설정')
left.addWidget(gb)
grid = QGridLayout()
gb.setLayout(grid)
label = QLabel('펜 색상')
grid.addWidget(label, 1, 0)
self.pencolor = QColor(0, 0, 0)
self.penbtn = QPushButton()
self.penbtn.setStyleSheet('background-color: rgb(0,0,0)')
self.penbtn.clicked.connect(self.showColorDlg)
grid.addWidget(self.penbtn, 1, 1)
label = QLabel('펜 굵기')
grid.addWidget(label, 2, 0)
self.slider = QSlider(Qt.Horizontal)
self.slider.setMinimum(3)
self.slider.setMaximum(21)
self.slider.setValue(5)
self.slider.setFocusPolicy(Qt.StrongFocus)
self.slider.setTickPosition(QSlider.TicksBothSides)
self.slider.setTickInterval(1)
self.slider.setSingleStep(1)
grid.addWidget(self.slider)
# 그룹박스4
gb = QGroupBox('지우개')
left.addWidget(gb)
hbox = QHBoxLayout()
gb.setLayout(hbox)
self.checkbox = QCheckBox('지우개')
self.checkbox.stateChanged.connect(self.checkClicked)
hbox.addWidget(self.checkbox)
left.addStretch(1)
# 우 레이아웃 박스에 그래픽 뷰 추가
self.view = CView(self)
right.addWidget(self.view)
# 전체 폼박스에 좌우 박스 배치
formbox.addLayout(left)
formbox.addLayout(right)
formbox.setStretchFactor(left, 0)
formbox.setStretchFactor(right, 1)
self.setGeometry(100, 100, 800, 500)
def checkClicked(self):
pass
def createExampleGroup(self):
groupBox = QGroupBox("Slider Example")
slider = QSlider(Qt.Horizontal)
slider.setFocusPolicy(Qt.StrongFocus)
slider.setTickPosition(QSlider.TicksBothSides)
slider.setTickInterval(10)
slider.setSingleStep(1)
vbox = QVBoxLayout()
vbox.addWidget(slider)
vbox.addStretch(1)
groupBox.setLayout(vbox)
return groupBox
def showColorDlg(self):
# 색상 대화상자 생성
color = QColorDialog.getColor()
sender = self.sender()
# 색상이 유효한 값이면 참, QFrame에 색 적용
self.pencolor = color
self.penbtn.setStyleSheet('background-color: {}'.format(color.name()))
# QGraphicsView display QGraphicsScene
class CView(QGraphicsView):
def __init__(self, parent):
super().__init__(parent)
self.scene = QGraphicsScene()
self.setScene(self.scene)
self.items = []
self.start = QPointF()
self.end = QPointF()
self.setRenderHint(QPainter.HighQualityAntialiasing)
def moveEvent(self, e):
rect = QRectF(self.rect())
rect.adjust(0, 0, -2, -2)
self.scene.setSceneRect(rect)
def mousePressEvent(self, e):
if e.button() == Qt.LeftButton:
# 시작점 저장
self.start = e.pos()
self.end = e.pos()
def mouseMoveEvent(self, e):
# e.buttons()는 정수형 값을 리턴, e.button()은 move시 Qt.Nobutton 리턴
if e.buttons() & Qt.LeftButton:
self.end = e.pos()
if self.parent().checkbox.isChecked():
pen = QPen(QColor(255, 255, 255), 10)
path = QPainterPath()
path.moveTo(self.start)
path.lineTo(self.end)
self.scene.addPath(path, pen)
self.start = e.pos()
return None
pen = QPen(self.parent().pencolor, self.parent().slider.value())
# Path 이용
path = QPainterPath()
path.moveTo(self.start)
path.lineTo(self.end)
self.scene.addPath(path, pen)
# 시작점을 다시 기존 끝점으로
self.start = e.pos()
def open(self):
fileName, _ = QFileDialog.getOpenFileName(self, "Open File",
QDir.currentPath())
if fileName:
image = QImage(fileName)
if image.isNull():
QMessageBox.information(self, "Image Viewer",
"Cannot load %s." % fileName)
return
self.imageLabel.setPixmap(QPixmap.fromImage(image))
self.scaleFactor = 1.0
self.printAct.setEnabled(True)
self.fitToWindowAct.setEnabled(True)
self.updateActions()
if not self.fitToWindowAct.isChecked():
self.imageLabel.adjustSize()
if __name__ == '__main__':
app = QApplication(sys.argv)
w = CWidget()
w.show()
sys.exit(app.exec_())

You can create an instance of QGraphicsPixmapItem and add it to the scene, here is an example:
import sys
from PyQt5.QtCore import *
from PyQt5.QtCore import Qt
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtWidgets import (QApplication, QCheckBox, QGridLayout, QGroupBox,
QPushButton, QVBoxLayout, QWidget, QSlider)
QApplication.setAttribute(Qt.AA_EnableHighDpiScaling, True)
class CWidget(QWidget):
def __init__(self):
super().__init__()
# 전체 폼 박스
formbox = QHBoxLayout()
self.setLayout(formbox)
# 좌, 우 레이아웃박스
left = QVBoxLayout()
right = QVBoxLayout()
# 그룹박스2
gb = QGroupBox('펜 설정')
left.addWidget(gb)
grid = QGridLayout()
gb.setLayout(grid)
label = QLabel('펜 색상')
grid.addWidget(label, 1, 0)
self.pencolor = QColor(0, 0, 0)
self.penbtn = QPushButton()
self.penbtn.setStyleSheet('background-color: rgb(0,0,0)')
self.penbtn.clicked.connect(self.showColorDlg)
grid.addWidget(self.penbtn, 1, 1)
label = QLabel('펜 굵기')
grid.addWidget(label, 2, 0)
self.slider = QSlider(Qt.Horizontal)
self.slider.setMinimum(3)
self.slider.setMaximum(21)
self.slider.setValue(5)
self.slider.setFocusPolicy(Qt.StrongFocus)
self.slider.setTickPosition(QSlider.TicksBothSides)
self.slider.setTickInterval(1)
self.slider.setSingleStep(1)
grid.addWidget(self.slider)
# 그룹박스4
gb = QGroupBox('지우개')
left.addWidget(gb)
hbox = QHBoxLayout()
gb.setLayout(hbox)
self.checkbox = QCheckBox('지우개')
self.checkbox.stateChanged.connect(self.checkClicked)
hbox.addWidget(self.checkbox)
left.addStretch(1)
# 우 레이아웃 박스에 그래픽 뷰 추가
self.view = CView(self)
right.addWidget(self.view)
# 전체 폼박스에 좌우 박스 배치
formbox.addLayout(left)
formbox.addLayout(right)
formbox.setStretchFactor(left, 0)
formbox.setStretchFactor(right, 1)
self.setGeometry(100, 100, 800, 500)
def checkClicked(self, state):
self.view.stretch(state)
def createExampleGroup(self):
groupBox = QGroupBox("Slider Example")
slider = QSlider(Qt.Horizontal)
slider.setFocusPolicy(Qt.StrongFocus)
slider.setTickPosition(QSlider.TicksBothSides)
slider.setTickInterval(10)
slider.setSingleStep(1)
vbox = QVBoxLayout()
vbox.addWidget(slider)
vbox.addStretch(1)
groupBox.setLayout(vbox)
return groupBox
def showColorDlg(self):
# 색상 대화상자 생성
color = QColorDialog.getColor()
sender = self.sender()
# 색상이 유효한 값이면 참, QFrame에 색 적용
self.pencolor = color
self.penbtn.setStyleSheet('background-color: {}'.format(color.name()))
# QGraphicsView display QGraphicsScene
class CView(QGraphicsView):
def __init__(self, parent):
super().__init__(parent)
self.scene = QGraphicsScene()
self.setScene(self.scene)
self.items = []
self.start = QPointF()
self.end = QPointF()
self.backgroundImage = None
self.graphicsPixmapItem = None
self.setRenderHint(QPainter.HighQualityAntialiasing)
self.open()
def moveEvent(self, e):
rect = QRectF(self.rect())
rect.adjust(0, 0, -2, -2)
self.scene.setSceneRect(rect)
def mousePressEvent(self, e):
if e.button() == Qt.LeftButton:
# 시작점 저장
self.start = e.pos()
self.end = e.pos()
def mouseMoveEvent(self, e):
# e.buttons()는 정수형 값을 리턴, e.button()은 move시 Qt.Nobutton 리턴
if e.buttons() & Qt.LeftButton:
self.end = e.pos()
if self.parent().checkbox.isChecked():
pen = QPen(QColor(255, 255, 255), 10)
path = QPainterPath()
path.moveTo(self.start)
path.lineTo(self.end)
self.scene.addPath(path, pen)
self.start = e.pos()
return None
pen = QPen(self.parent().pencolor, self.parent().slider.value())
# Path 이용
path = QPainterPath()
path.moveTo(self.start)
path.lineTo(self.end)
self.scene.addPath(path, pen)
# 시작점을 다시 기존 끝점으로
self.start = e.pos()
def stretch(self, state):
self._set_image(state == 2)
def open(self):
fileName, _ = QFileDialog.getOpenFileName(self, "Open File", QDir.currentPath(), filter='Images (*.png *.xpm *.jpg)')
if fileName:
image = QImage(fileName)
if image.isNull():
QMessageBox.information(self, "Image Viewer",
"Cannot load %s." % fileName)
return
self.backgroundImage = fileName
self._set_image(False)
def _set_image(self, stretch: bool):
tempImg = QPixmap(self.backgroundImage)
if stretch:
tempImg = tempImg.scaled(self.scene.width(), self.scene.height())
if self.graphicsPixmapItem is not None:
self.scene.removeItem(self.graphicsPixmapItem)
self.graphicsPixmapItem = QGraphicsPixmapItem(tempImg)
self.scene.addItem(self.graphicsPixmapItem)
if __name__ == '__main__':
app = QApplication(sys.argv)
w = CWidget()
w.show()
sys.exit(app.exec_())

PyQt5: How to click a button to move the paint?

In the following code, one rectangle is made when the "Paint" button is clicked. It contains also a "Move" button. By clicking the "Move" button I want to move the rectangle 1px in both x and y directions. But I failed here.
I can understand the question is about how to transfer variable values wenn a button is clicked. To a beginner it is very difficult for me. Any help will be highly appreciated!
# -*- coding: utf-8 -*-
from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QHBoxLayout, QDoubleSpinBox
from PyQt5.QtGui import QPainter, QColor, QBrush
import sys
class Example(QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
self.flag = False
def initUI(self):
self.setFixedSize(400, 400)
self.setWindowTitle('Colours')
self.btnPaint = QPushButton("Paint", self)
self.btnMove = QPushButton("Move x+1 y+1", self)
self.deltax = 0 # original value
self.deltay = 0 # original value
self.btnPaint.clicked.connect(self.onPaint)
self.btnMove.clicked.connect(self.onMove)
self.hlayout = QHBoxLayout()
self.hlayout.addWidget(self.btnPaint)
self.hlayout.addWidget(self.btnMove)
self.hlayout.addStretch(1)
self.setLayout(self.hlayout)
self.show()
def onPaint(self):
self.flag = True
self.update()
def onMove(self):
self.deltax = self.deltax + 1 # button clicked, value +1
self.deltay = self.deltay + 1 # button clicked, value +1
self.flag_move = True
self.update()
def paintEvent(self, e):
if self.flag:
qp = QPainter()
qp.begin(self)
self.drawRectangles(qp)
qp.end()
if self.flag_move:
qp = QPainter()
qp.begin(self)
self.drawRectangles(qp)
qp.end()
def drawRectangles(self, qp):
x1 = 10
y1 = 15
x2 = 90
y2 = 60
col = QColor(0, 0, 0)
col.setNamedColor('#d4d4d4')
qp.setPen(col)
qp.setBrush(QColor(200, 0, 0))
qp.drawRect(x1+self.deltax, y1+self.deltay, x2+self.deltax, y2+self.deltay)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())

Your code has an error because the self.flag_move is not initially defined, but it is not necessary to use so many variables either.
Qt has the QRect class that has several methods that make the task easier, initially we create a null QRect, and when the btnPaint button is pressed we will enable QRect to a non-null one. in the case of pressing the btnMove button we will use the translate method that moves the rectangle:
import sys
from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QHBoxLayout
from PyQt5.QtGui import QPainter, QColor, QBrush
from PyQt5.QtCore import QRect, QPoint
class Example(QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.setFixedSize(400, 400)
self.setWindowTitle('Colours')
self.btnPaint = QPushButton("Paint", self)
self.btnMove = QPushButton("Move x+1 y+1", self)
self.rect = QRect()
self.btnPaint.clicked.connect(self.onPaint)
self.btnMove.clicked.connect(self.onMove)
self.hlayout = QHBoxLayout(self)
self.hlayout.addWidget(self.btnPaint)
self.hlayout.addWidget(self.btnMove)
self.hlayout.addStretch(1)
self.show()
def onPaint(self):
if self.rect.isNull():
self.rect = QRect(10, 15, 80, 45)
self.update()
def onMove(self):
if not self.rect.isNull():
self.rect.translate(QPoint(1, 1))
self.update()
def paintEvent(self, e):
qp = QPainter(self)
qp.setPen(QColor("#d4d4d4"))
qp.setBrush(QColor(200, 0, 0))
qp.drawRect(self.rect)