I am trying to use QPainter to draw a line between two widgets. If I use a simple function inside the first class it works. But, I want to create a separate class of a QPainter event, that I can call at the first class whenever I want. But, it is not working as expected. Can you help me to figure out why the QPainter class is not adding a line.
import sys
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.okButton = QPushButton("OK")
self.cancelButton = QPushButton("Cancel")
l1 = self.okButton.pos()
l2 = self.cancelButton.pos()
# This is to call the class to draw a line between those two widgets
a = QPaint(l1.x(), l1.y(), l2.x(), l2.y(),parent=self)
vbox = QVBoxLayout()
vbox.addWidget(self.okButton)
vbox.addWidget(self.cancelButton)
self.setLayout(vbox)
self.setGeometry(300, 300, 300, 150)
self.setWindowTitle('Buttons')
self.show()
class QPaint(QPainter):
def __init__(self, x1, y1, x2, y2, parent=None):
super().__init__()
def paintEvent(self, event):
self.setPen(Qt.red)
self.drawLine(x1,y1,x2,y2)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
Widgets can only be painted in the widget's paintEvent method, so if you don't want to paint it in the same class then you can use multiple inheritance. On the other hand, the initial positions you use to paint will be the positions before showing that they are 0 making no line is painted but a point so it is better to track the positions using an event filter.
import sys
from PyQt5.QtCore import QEvent
from PyQt5.QtGui import QPainter
from PyQt5.QtWidgets import QApplication, QPushButton, QVBoxLayout, QWidget
class Drawer:
def paintEvent(self, event):
painter = QPainter(self)
painter.drawLine(self.p1, self.p2)
class Example(QWidget, Drawer):
def __init__(self, parent=None):
super().__init__(parent)
self.initUI()
def initUI(self):
self.okButton = QPushButton("OK")
self.cancelButton = QPushButton("Cancel")
vbox = QVBoxLayout(self)
vbox.addWidget(self.okButton)
vbox.addWidget(self.cancelButton)
self.setGeometry(300, 300, 300, 150)
self.setWindowTitle("Buttons")
self.p1, self.p2 = self.okButton.pos(), self.cancelButton.pos()
self.okButton.installEventFilter(self)
self.cancelButton.installEventFilter(self)
def eventFilter(self, o, e):
if e.type() == QEvent.Move:
if o is self.okButton:
self.p1 = self.okButton.pos()
elif o is self.cancelButton:
self.p2 = self.cancelButton.pos()
self.update()
return super().eventFilter(o, e)
if __name__ == "__main__":
app = QApplication(sys.argv)
ex = Example()
ex.show()
sys.exit(app.exec_())
Related
This question already has answers here:
How do I assert the identity of a PyQt5 signal?
(2 answers)
Closed 2 years ago.
I've created a search engine in PyQt5, using the code below:
import sys
from PyQt5.QtWidgets import (
QWidget, QLineEdit, QLabel, QScrollArea, QMainWindow,
QApplication, QHBoxLayout, QVBoxLayout, QSpacerItem, QSizePolicy, QCompleter, QPushButton
)
from PyQt5 import QtCore
from PyQt5.QtCore import Qt
tlist = ['thing1', 'thing2', 'thing3', 'thing4']
class Label(QWidget):
def __init__(self, name):
super(Label, self).__init__()
self.name = name
self.lbl = QLabel(self.name)
self.lbl.setTextInteractionFlags(QtCore.Qt.TextSelectableByMouse)
self.btn = QPushButton("Preview")
self.btn.setMaximumSize(QtCore.QSize(100,100))
self.btn.clicked.connect(self.printsignal)
self.hbox = QHBoxLayout()
self.hbox.addWidget(self.lbl)
self.hbox.addWidget(self.btn)
self.setLayout(self.hbox)
def show(self):
for labels in [self, self.lbl]:
labels.setVisible(True)
def hide(self):
for labels in [self, self.lbl]:
labels.setVisible(False)
def printsignal(self):
print("clicked")
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super().__init__()
self.controls = QWidget()
self.controlsLayout = QVBoxLayout()
self.widgets = []
for name in tlist:
item = Label(name)
self.controlsLayout.addWidget(item)
self.widgets.append(item)
spacer = QSpacerItem(1, 1, QSizePolicy.Minimum, QSizePolicy.Expanding)
self.controlsLayout.addItem(spacer)
self.controls.setLayout(self.controlsLayout)
self.scroll = QScrollArea()
self.scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
self.scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.scroll.setWidgetResizable(True)
self.scroll.setWidget(self.controls)
self.searchbar = QLineEdit()
self.searchbar.textChanged.connect(self.update_display)
self.completer = QCompleter(tlist)
self.completer.setCaseSensitivity(Qt.CaseInsensitive)
self.searchbar.setCompleter(self.completer)
container = QWidget()
containerLayout = QVBoxLayout()
containerLayout.addWidget(self.searchbar)
containerLayout.addWidget(self.scroll)
container.setLayout(containerLayout)
self.setCentralWidget(container)
self.setGeometry(600, 100, 800, 600)
self.setWindowTitle('Search Engine')
def update_display(self, text):
for widget in self.widgets:
if text.lower() in widget.name.lower():
widget.show()
else:
widget.hide()
app = QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
The problem I have is, all the buttons share the same function and I don't know how to make them have different signals, as they are generated automatically. Basically, if I run the code it will show up like
this:
and when I press any of the buttons, it will print "clicked" (as in printsignal function). What I want is a different function for each button. Is there a way to do that?
Normally you can use self.sender().text() to get text from QButton which generated signal.
But because you create own widget Label with QButton and QLabel and you want text from label so you can get directly self.name
def printsignal(self):
print("clicked", self.name)
eventually self.lbl.text()
def printsignal(self):
print("clicked", self.lbl.text())
Working code.
I removed show(), hide() because you don't need it
import sys
from PyQt5.QtWidgets import (
QWidget, QLineEdit, QLabel, QScrollArea, QMainWindow,
QApplication, QHBoxLayout, QVBoxLayout, QSpacerItem, QSizePolicy, QCompleter, QPushButton
)
from PyQt5 import QtCore
from PyQt5.QtCore import Qt
tlist = ['thing1', 'thing2', 'thing3', 'thing4']
class Label(QWidget):
def __init__(self, name):
super().__init__()
self.name = name
self.lbl = QLabel(self.name)
self.lbl.setTextInteractionFlags(QtCore.Qt.TextSelectableByMouse)
self.btn = QPushButton("Preview")
self.btn.setMaximumSize(QtCore.QSize(100,100))
self.btn.clicked.connect(self.printsignal)
self.hbox = QHBoxLayout()
self.hbox.addWidget(self.lbl)
self.hbox.addWidget(self.btn)
self.setLayout(self.hbox)
def printsignal(self):
print("clicked", self.name)
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super().__init__()
self.controls = QWidget()
self.controlsLayout = QVBoxLayout()
self.widgets = []
for name in tlist:
item = Label(name)
self.controlsLayout.addWidget(item)
self.widgets.append(item)
spacer = QSpacerItem(1, 1, QSizePolicy.Minimum, QSizePolicy.Expanding)
self.controlsLayout.addItem(spacer)
self.controls.setLayout(self.controlsLayout)
self.scroll = QScrollArea()
self.scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
self.scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.scroll.setWidgetResizable(True)
self.scroll.setWidget(self.controls)
self.searchbar = QLineEdit()
self.searchbar.textChanged.connect(self.update_display)
self.completer = QCompleter(tlist)
self.completer.setCaseSensitivity(Qt.CaseInsensitive)
self.searchbar.setCompleter(self.completer)
container = QWidget()
containerLayout = QVBoxLayout()
containerLayout.addWidget(self.searchbar)
containerLayout.addWidget(self.scroll)
container.setLayout(containerLayout)
self.setCentralWidget(container)
self.setGeometry(600, 100, 800, 600)
self.setWindowTitle('Search Engine')
def update_display(self, text):
for widget in self.widgets:
if text.lower() in widget.name.lower():
widget.show()
else:
widget.hide()
app = QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
I have a main widget inside a window who contains a lot of widgets. How can I insert a QGraphics view and a QGraphicsScene in that widget? I have not found a direct insertion method, so I am trying using a wrapper, in this case a box layout but it is not a good solution. The QGraphicsScene stands out from the layout limits.
Code:
class UiVentana(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.setFixedSize(1500, 1015)
widget_central = QtWidgets.QWidget(self)
wrapper = QtWidgets.QHBoxLayout(widget_central)
scene = QtWidgets.QGraphicsScene(wrapper)
vista = QtWidgets.QGraphicsView(scene)
wrapper.addWidget(vista)
self.diedrico = Diedrico() # This is a class who draw things, not relevant
self.diedrico.setFixedSize(2000, 2000)
scene.addWidget(self.diedrico)
self.setCentralWidget(widget_central)
I would like to get this result:
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QWidget
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPainter, QPen, QColor
import sys
class Diedrico(QWidget):
def __init__(self, parent):
super().__init__(parent)
def paintEvent(self, event):
qp = QPainter(self)
qp.setPen(QPen(QColor(Qt.black), 5))
qp.drawRect(500, 500, 1000, 1000)
class UiVentana(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self.resize(520, 520)
self.widget_central = QtWidgets.QWidget(self)
scrol = QtWidgets.QScrollArea(self.widget_central)
scrol.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
scrol.setGeometry(QtCore.QRect(30, 30, 500, 500))
scrol.setWidgetResizable(False)
contenido = QtWidgets.QWidget()
contenido.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
scrol.setWidget(contenido)
self.Diedrico = Diedrico(contenido)
self.Diedrico.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
self.setCentralWidget(self.widget_central)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
But using QGraphics instead of a scroll area
The QGraphicsProxyWidget that is created using the widget takes into account the minimum size of the widget to set the boundingRect, and the QGraphicsScene uses the boundingRect to set the initial scene rect.
from PyQt5 import QtCore, QtGui, QtWidgets
class Diedrico(QtWidgets.QWidget):
def paintEvent(self, event):
qp = QtGui.QPainter(self)
pen = QtGui.QPen(QtGui.QColor(QtCore.Qt.black), 5)
qp.setPen(pen)
qp.drawRect(500, 500, 1000, 1000)
def minimumSizeHint(self):
return QtCore.QSize(2000, 2000)
class UiVentana(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self.resize(520, 520)
widget_central = QtWidgets.QWidget()
self.setCentralWidget(widget_central)
lay = QtWidgets.QVBoxLayout(widget_central)
scene = QtWidgets.QGraphicsScene(self)
view = QtWidgets.QGraphicsView(scene)
diedrico = Diedrico()
scene.addWidget(diedrico)
lay.addWidget(view)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
How can I make a zoom effect with key input on a widget? The widget is inside a scroll area and there are some drawings made with QPainter who change with user input. The zoom would affect the length of the scrolling bar, the closer you are, the smaller the bar becomes. The zoom at minimum level should make the scroll bar as big as the widget area, so all the content in the widget could be visualized.
MRE:
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QWidget
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPainter, QPen, QColor
import sys
class Diedrico(QWidget):
def __init__(self, parent):
super().__init__(parent)
def paintEvent(self, event):
qp = QPainter(self)
qp.setPen(QPen(QColor(Qt.black), 5))
qp.drawRect(500, 500, 1000, 1000)
class UiVentana(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self.resize(520, 520)
self.widget_central = QtWidgets.QWidget(self)
scrol = QtWidgets.QScrollArea(self.widget_central)
scrol.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
scrol.setGeometry(QtCore.QRect(10, 10, 500, 500))
scrol.setWidgetResizable(False)
contenido = QtWidgets.QWidget()
contenido.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
scrol.setWidget(contenido)
self.Diedrico = Diedrico(contenido)
self.Diedrico.setGeometry(QtCore.QRect(0, 0, 2000, 2000))
self.setCentralWidget(self.widget_central)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
Why do you want to reinvent the wheel? Instead of wanting to implement the logic of the scaling feature, use the classes that already do it. In this case, a good option is to use QGraphicsView with QGraphicsScene:
Note: The shortcut standard Zoom In and Zoom Out are associated with Ctrl + + and Ctrl + -, respectively.
from PyQt5 import QtCore, QtGui, QtWidgets
class Diedrico(QtWidgets.QWidget):
def paintEvent(self, event):
qp = QtGui.QPainter(self)
pen = QtGui.QPen(QtGui.QColor(QtCore.Qt.black), 5)
qp.setPen(pen)
qp.drawRect(500, 500, 1000, 1000)
class UiVentana(QtWidgets.QMainWindow):
factor = 1.5
def __init__(self, parent=None):
super(UiVentana, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self._view = QtWidgets.QGraphicsView(self._scene)
self._diedrico = Diedrico()
self._diedrico.setFixedSize(2000, 2000)
self._scene.addWidget(self._diedrico)
self.setCentralWidget(self._view)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtGui.QKeySequence.ZoomIn),
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_in,
)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtGui.QKeySequence.ZoomOut),
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_out,
)
#QtCore.pyqtSlot()
def zoom_in(self):
scale_tr = QtGui.QTransform()
scale_tr.scale(UiVentana.factor, UiVentana.factor)
tr = self._view.transform() * scale_tr
self._view.setTransform(tr)
#QtCore.pyqtSlot()
def zoom_out(self):
scale_tr = QtGui.QTransform()
scale_tr.scale(UiVentana.factor, UiVentana.factor)
scale_inverted, invertible = scale_tr.inverted()
if invertible:
tr = self._view.transform() * scale_inverted
self._view.setTransform(tr)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
ui = UiVentana()
ui.show()
sys.exit(app.exec_())
Update:
If you want to use + and - for ZoomIn and ZoomOut, respectively, then just change the shortcuts to:
QtWidgets.QShortcut(
QtGui.QKeySequence(QtCore.Qt.Key_Plus), # <---
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_in,
)
QtWidgets.QShortcut(
QtGui.QKeySequence(QtCore.Qt.Key_Minus), # <---
self._view,
context=QtCore.Qt.WidgetShortcut,
activated=self.zoom_out,
)
The example shown below adds a very simple custom pyqt5 widget to a QScrollArea. When i move the custom widget "off" the area of the scroll area I would expect that scrollbars should appear. Obviously this is not the case.
#!/usr/bin/python3
from PyQt5.QtWidgets import QMainWindow, QWidget, QApplication, QScrollArea
from PyQt5.QtCore import QObject
from PyQt5.QtGui import QPainter, QColor, QPen
import sys
class ExampleWidget(QWidget):
def __init__(self, parent=None):
super().__init__(parent=parent)
def paintEvent(self, e):
qp = QPainter()
qp.begin(self)
self.drawWidget(qp)
qp.end()
def drawWidget(self, qp):
qp.setPen(QColor(255, 0, 0))
qp.setBrush(QColor(255, 0, 0))
qp.drawRect(0, 0, 100, 100)
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.setGeometry(300, 300, 300, 200)
self.scrollArea = QScrollArea(self)
self.setCentralWidget(self.scrollArea)
self.widget = ExampleWidget(self.scrollArea)
self.widget.setGeometry(250, 150, 100, 100)
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
How can I make the scrollbars appear once a widget is moved so it's not visible completely anymore?
In the code that samples ExampleWidget is a child of QScrollArea: self.widget = ExampleWidget(self.scrollArea), that does not imply that the widget is handled with the properties of the QScrollArea, the QScrollArea has a viewport() that is the background widget and the QScrollArea only shows a part of it. So if you want a widget to be inside you have to use the setWidget() method. On the other hand that viewport() has the size of the content and how it calculates that size ?, by default it uses the sizeHint() of the widget, and in your case it does not have it so it will not show what you want.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class ExampleWidget(QtWidgets.QWidget):
def paintEvent(self, e):
qp = QtGui.QPainter(self)
self.drawWidget(qp)
def drawWidget(self, qp):
qp.setPen(QtGui.QColor(255, 0, 0))
qp.setBrush(QtGui.QColor(255, 0, 0))
qp.drawRect(0, 0, 100, 100)
def sizeHint(self):
return QtCore.QSize(500, 500)
class Example(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.scrollArea = QtWidgets.QScrollArea()
self.setCentralWidget(self.scrollArea)
self.widget = ExampleWidget()
self.scrollArea.setWidget(self.widget)
self.show()
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
I have a QMainWindow with a toolbar, and I'm having troubles with fitting the QPixmap to the window, such that it won't tackle with the toolbar.
I want to display the picture:
And from the code:
import sys
from PyQt5.QtCore import QRect
from PyQt5.QtWidgets import QAction, QMainWindow, QApplication
from PyQt5.QtGui import QPixmap, QPainter
class Menu(QMainWindow):
def __init__(self):
super().__init__()
newAct = QAction('New', self)
self.toolbar = self.addToolBar('Remove')
self.toolbar.addAction(newAct)
self.image = QPixmap("background.png")
self.setGeometry(100, 30, 500, 300)
self.resize(self.image.width(), self.image.height())
self.show()
def paintEvent(self, event):
painter = QPainter(self)
rect = QRect(0, 0, self.image.width(), self.image.height())
painter.drawPixmap(rect, self.image)
if __name__ == '__main__':
app = QApplication(sys.argv)
mainMenu = Menu()
sys.exit(app.exec_())
I get:
And as you can see, The picture is on the toolbar as well, and I don't want that.
Another try:
import sys
from PyQt5.QtCore import QRect
from PyQt5.QtWidgets import QAction, QMainWindow, QApplication
from PyQt5.QtGui import QPixmap, QPainter
class Menu(QMainWindow):
def __init__(self):
super().__init__()
newAct = QAction('New', self)
self.toolbar = self.addToolBar('Remove')
self.toolbar.addAction(newAct)
self.image = QPixmap("background.png")
self.setGeometry(100, 30, 500, 300)
self.resize(self.image.width(), self.image.height() + self.toolbar.height())
self.show()
def paintEvent(self, event):
painter = QPainter(self)
rect = QRect(0, self.toolbar.height(), self.image.width(), self.image.height() + self.toolbar.height())
painter.drawPixmap(rect, self.image)
if __name__ == '__main__':
app = QApplication(sys.argv)
mainMenu = Menu()
sys.exit(app.exec_())
But I get:
And as you can see, I don't see one of the lines (the blue one).
How can I fix it, so the picture will fit the window excluding the toolbar?
In addition to that, it means I'll have to change all my mouse clicks to move the y-axis. Is there perhaps a way I can set everything such that (x,y)=(0,0) would be at the uppermost left, below the toolbar?
I'm using Python 3.6.5 |Anaconda custom (64-bit) on windows | PyQt version: 5.9.2
Although I can not reproduce the problem, the following solution must work, in it I draw the image in a widget and I set them as centralwidget.
import sys
from PyQt5.QtCore import QRect
from PyQt5.QtWidgets import QAction, QMainWindow, QApplication, QWidget
from PyQt5.QtGui import QPixmap, QPainter
class Widget(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.image = QPixmap("background.png")
self.setFixedSize(self.image.size())
def paintEvent(self, event):
painter = QPainter(self)
painter.drawPixmap(self.rect(), self.image)
class Menu(QMainWindow):
def __init__(self):
super().__init__()
newAct = QAction('New', self)
self.toolbar = self.addToolBar('Remove')
self.toolbar.addAction(newAct)
self.setCentralWidget(Widget())
self.setFixedSize(self.sizeHint())
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
mainMenu = Menu()
sys.exit(app.exec_())