I want to upgrade or convert this code from pyqt4 to pyqt5 as this code is not compatible with latest pyqt5.
So can someone tell me what major changes i can make in this code to run it in pyqt5.
import sys
from PyQt4.QtCore import Qt
from PyQt4.QtCore import QRectF
from PyQt4.QtWidgets import QApplication
from PyQt4.QtGui import QColor
from PyQt4.QtGui import QFont
from PyQt4.QtGui import QPainter
from PyQt4.QtGui import QPixmap
from PyQt4.QtGui import QTextOption
from PyQt4.QtGui import QToolTip
from PyQt4.QtGui import QWidget
this are all the imported libraries for this code
class AreaSelector(QWidget):
def __init__(self, parent=None):
QWidget.__init__(self, None, Qt.FramelessWindowHint)
self.setAttribute(Qt.WA_TranslucentBackground)
self.setAttribute(Qt.WA_DeleteOnClose)
self.setWindowState(Qt.WindowFullScreen)
self.setAutoFillBackground(False)
self.parent = parent
self.start_x = 0
self.start_y = 0
self.end_x = 0
self.end_y = 0
self.current_x = 0
self.current_y = 0
def showEvent(self, event):
self.bg = QPixmap.grabWindow(QApplication.desktop().winId())
self.screen_geometry = QApplication.desktop().screenGeometry(self)
def mousePressEvent(self, event):
self.start_x = event.globalX()
self.start_y = event.globalY()
def mouseReleaseEvent(self, event):
self.end_x = event.globalX()
self.end_y = event.globalY()
please view the full code here full code
Translating a PyQt4 code to PyQt5 is not a trivial task:
PyQt4 and PyQt5 are wrappers of Qt4 and Qt5, respectively, so both are affected by the changes of that transition, and one of the transitions is that the QtGui sub-module of Qt4 was divided into the QtGui and QtWidgets sub-modules of Qt5.
Some classes and methods are deprecated so you will have to find an equivalent if it exists.
In this case both things happen, the solution for the first case is simple: You must look in the Qt docs and check to which sub-module it belongs, for example QToolTip, at the top there is a table:
And the part of QT += widgets that indicates that it belongs to the QtWidgets sub-module is observed.
But the second case is somewhat more complicated since it involves looking for an equivalent that may or may not be in the same class, in this case it happens with the QPixmap.grabWindow() method which is deprecates (see here for more information). After doing a search you can replace that code with QApplication.primaryScreen().grabWindow(0).
Considering all of the above, the translation is:
import sys
from PyQt5.QtCore import QRectF, Qt
from PyQt5.QtGui import QColor, QFont, QPainter, QPixmap, QTextOption, QScreen
from PyQt5.QtWidgets import QApplication, QToolTip, QWidget
class AreaSelector(QWidget):
def __init__(self, parent=None):
QWidget.__init__(self, None, Qt.FramelessWindowHint)
self.setAttribute(Qt.WA_TranslucentBackground)
self.setAttribute(Qt.WA_DeleteOnClose)
self.setWindowState(Qt.WindowFullScreen)
self.setAutoFillBackground(False)
self.parent = parent
self.start_x = 0
self.start_y = 0
self.end_x = 0
self.end_y = 0
self.current_x = 0
self.current_y = 0
def showEvent(self, event):
self.bg = QApplication.primaryScreen().grabWindow(0)
self.screen_geometry = QApplication.primaryScreen().geometry()
def mousePressEvent(self, event):
self.start_x = event.globalX()
self.start_y = event.globalY()
def mouseReleaseEvent(self, event):
self.end_x = event.globalX()
self.end_y = event.globalY()
def mouseMoveEvent(self, event):
self.current_x = event.globalX()
self.current_y = event.globalY()
self.repaint()
text = "Start: %sx%s \nEnd: %sx%s" % (
self.start_x,
self.start_y,
self.current_x,
self.current_y,
)
QToolTip.showText(event.pos(), text)
def keyPressEvent(self, event):
if event.key() == Qt.Key_Return:
self._acceptSelection()
elif event.key() == Qt.Key_Escape:
self.close()
def _acceptSelection(self):
if self.parent is not None:
self.parent.areaSelectEvent(
self.start_x, self.start_y, self.end_x, self.end_y
)
self.close()
def paintEvent(self, event):
painter = QPainter()
painter.begin(self)
painter.fillRect(self.screen_geometry, QColor(10, 10, 10, 125))
self._paint_selection(painter)
self._paint_usage_text(painter)
painter.end()
def _paint_usage_text(self, painter):
font = QFont("Helvetica [Cronyx]", 26, QFont.Bold)
painter.setFont(font)
painter.setPen(QColor(255, 255, 255, 255))
screen_width = self.screen_geometry.width()
text_width = 800
text_start_x = screen_width / 2 - text_width / 2
screen_height = self.screen_geometry.height()
text_height = 200
text_start_y = screen_height / 2 - text_height / 2
textoption = QTextOption(Qt.AlignCenter)
textbox = QRectF(text_start_x, text_start_y, text_width, text_height)
painter.drawText(
textbox,
"Click & Drag to select an area\n" "ENTER to confirm or ESC to cancel",
textoption,
)
painter.drawRoundedRect(textbox, 20, 20)
def _paint_selection(self, painter):
"""Draws the current user selection"""
rectangle = QRectF()
if self.start_x > self.current_x:
rectangle.setLeft(self.current_x)
rectangle.setRight(self.start_x)
else:
rectangle.setLeft(self.start_x)
rectangle.setRight(self.current_x)
if self.start_y > self.current_y:
rectangle.setTop(self.current_y)
rectangle.setBottom(self.start_y)
else:
rectangle.setTop(self.start_y)
rectangle.setBottom(self.current_y)
painter.drawPixmap(rectangle, self.bg, rectangle)
painter.drawRect(rectangle)
if __name__ == "__main__":
app = QApplication(sys.argv)
main = AreaSelector()
main.show()
sys.exit(app.exec_())
Related
The code below sketches a polygon on an image. I would like to draw a second identical shape inside the primary one with a gap of 0.3m. I have tried a couple of solutions but none of them worked in all use cases.
Please refer to the attached screenshot.
Context: The shape is drawn by combining a group of selected points using the QPolygon class.
import sys
from sympy import Polygon
from PyQt5.QtWidgets import QApplication, QWidget, QHBoxLayout, QVBoxLayout
from PyQt5.QtCore import QLine, Qt, QPoint, QRect
from PyQt5.QtGui import QPixmap, QPainter,QColor,QPolygon
from PyQt5 import QtCore, QtGui, QtWidgets, uic
class MyApp(QWidget):
def __init__(self):
super().__init__()
self.window_width, self.window_height =1200,800
self.setMinimumSize(self.window_width,self.window_height)
layout= QVBoxLayout()
self.setLayout(layout)
self.pix = QPixmap('image.jpg')
self.resize(self.pix.width(),self.pix.height())
# self.pix.fill(Qt.white)
# tableau
self.point = QPoint()
self.tab =[]
def paintEvent(self,event):
painter = QPainter(self)
pen = QtGui.QPen()
pen.setColor(QtGui.QColor('red'))
pen.setWidth(3)
painter.setPen(pen)
painter.drawPixmap(QPoint(),self.pix)
if not self.point.isNull():
# rect = QRect(self.begin,self.destination)
# painter.drawRect(rect.normalized())
line = QPoint(self.point)
painter.drawPoint(line)
def mousePressEvent(self,event):
if event.buttons() & Qt.LeftButton:
self.point = event.pos()
# self.destination = self.begin
self.update()
# def mouseMoveEvent(self,event):
# if event.buttons() & Qt.LeftButton:
# self.point = event.pos()
# self.update()
def mouseReleaseEvent(self,event):
pen = QtGui.QPen()
painter = QPainter(self.pix)
if event.button() == Qt.LeftButton:
# rect = QRect(self.begin,self.destination)
line = QPoint(self.point)
pen.setColor(QtGui.QColor('red'))
pen.setWidth(3)
painter.setPen(pen)
painter.drawPoint(line)
painter.setPen(QColor(168, 34, 3))
self.tab.append(self.point)
print(self.point.x,self.point.y)
self.point = QPoint()
# w = (rect.width()*12.5)/1056
# h = (rect.height()*12.5/1056)
# a=w*h
# print(w, h,a)
self.update()
if event.button() == Qt.RightButton:
points = QPolygon(self.tab)
pen.setColor(QtGui.QColor('red'))
painter.setPen(pen)
painter.drawPolygon(points)
#print(self.tab[0])
polytab=[]
for i in self.tab:
polytab.append((i.x(),i.y()))
print(Polygon(*polytab).area*(12.5/1056)*(12.5/1056))
print((self.tab[0].x()-self.tab[1].x())*(12.5/1056))
self.tab=[]
self.update()
if __name__ == '__main__':
app = QApplication(sys.argv)
app.setStyleSheet('''QWidget{font-size:30px}''')
myAPP = MyApp()
myAPP.show()
try:
sys.exit(app.exec_())
except SystemExit:
print('Closing Window...')
The algorithm is given a vertex so the associated edges must be translated in a parallel way and the intersection of these lines is a point of the desired polygon.
import sys
from PyQt5.QtCore import QLineF
from PyQt5.QtGui import QColor, QPainter, QPen, QPolygonF
from PyQt5.QtWidgets import QApplication, QWidget
def calculate_inner_polygon(polygon, offset):
if polygon.count() < 3:
return QPolygonF()
points = []
for i in range(polygon.count()):
pp = polygon[(i - 1 + polygon.count()) % polygon.count()]
pc = polygon[i]
pn = polygon[(i + 1 + polygon.count()) % polygon.count()]
line_0 = QLineF(pp, pc)
normal_0 = line_0.normalVector()
normal_0.setLength(offset)
line_0.translate(normal_0.dx(), normal_0.dy())
line_1 = QLineF(pc, pn)
normal_1 = line_1.normalVector()
normal_1.setLength(offset)
line_1.translate(normal_1.dx(), normal_1.dy())
t, point = line_0.intersects(line_1)
if t != QLineF.NoIntersection:
points.append(point)
return QPolygonF(points)
class MyApp(QWidget):
def __init__(self):
super().__init__()
self.setMinimumSize(1200, 800)
self._points = list()
def paintEvent(self, event):
painter = QPainter(self)
painter.fillRect(self.rect(), QColor("white"))
if not self._points:
return
pen_width = 3
offset = -8
pen = QPen(QColor("red"))
outer_polygon = QPolygonF(self._points)
inner_polygon = calculate_inner_polygon(outer_polygon, offset)
for polygon in (outer_polygon, inner_polygon):
pen.setWidth(pen_width)
painter.setPen(pen)
painter.drawPolygon(polygon)
pen.setWidth(2 * pen_width)
painter.setPen(pen)
for point in polygon:
painter.drawPoint(point)
def mouseReleaseEvent(self, event):
self._points.append(event.pos())
self.update()
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MyApp()
w.show()
sys.exit(app.exec_())
I am trying to build a paint app that has a grid, but I don't want to grid to be included in the saved photo.
I tried to draw on a transparent image, but I got a black background instead!
Here is the full code:
import sys
from PyQt5 import QtGui, QtWidgets, QtCore
from PyQt5.QtCore import QPoint, Qt
from PyQt5.QtGui import QBrush, QGuiApplication, QImage, QPainter, QPen, QIcon, QColor
from PyQt5.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget, QTextEdit, QAction, QFileDialog,
QGraphicsScene, QGraphicsProxyWidget, QGraphicsView
import pyautogui
import matplotlib.pyplot as plt
class Drawer(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self._drawing = False
self.last_point = QPoint()
self.image_layer = QImage(self.size(), QImage.Format_RGB32)
self.image_layer.fill(Qt.gray)
self.brushSize = 2
self.brushColor = Qt.black
#paint = QPainter(self.image_layer)
#paint.setCompositionMode(QtGui.QPainter.CompositionMode_Clear)
# paint.drawLine(0,0,self.size().width(),0)
# paint.drawLine(0,10,200,10)
#paint.drawLine(0,0,0,200)
#paint.drawLine(10,0,10,200)
self.update()
def mousePressEvent(self, event):
self._drawing = True
self.last_point = event.pos()
def mouseMoveEvent(self, event):
if self._drawing and event.buttons() & Qt.LeftButton:
painter = QPainter(self.image_layer)
painter.setPen(
QPen(
self.brushColor,
self.brushSize,
Qt.SolidLine,
Qt.RoundCap,
Qt.RoundJoin,
)
)
painter.drawLine(self.last_point, event.pos())
self.last_point = event.pos()
self.update()
def paintEvent(self, event):
painter = QPainter(self)
painter.drawImage(QPoint(), self.image_layer)
painter.end()
def resizeEvent(self, event):
if (
self.size().width() > self.image_layer.width()
or self.size().height() > self.image_layer.height()
):
qimg = QImage(
max(self.size().width(), self.image_layer.width()),
max(self.size().height(), self.image_layer.height()),
QImage.Format_RGB32,
)
qimg.fill(Qt.gray)
painter = QPainter(qimg)
painter.drawImage(QPoint(), self.image_layer)
painter.drawLine(0, 0, qimg.size().width(), 0)
painter.drawLine(0, 10, qimg.size().width(), 10)
painter.drawLine(0, 600, qimg.size().width(), 600)
print(qimg.size().height())
painter.end()
self.image_layer = qimg
self.update()
class Window(QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
[x, y] = pyautogui.size()
self.setGeometry(0, 0, x, y)
self.drawer = Drawer()
textbox = QTextEdit("Converted text will show here")
central_widget = QWidget()
self.setCentralWidget(central_widget)
vlay = QVBoxLayout(central_widget)
vlay.addWidget(textbox)
vlay.addWidget(self.drawer, stretch=1)
mainMenu = self.menuBar()
fileMenu = mainMenu.addMenu("File")
saveAction = QAction(QIcon("icons/save.png"), "Save", self)
saveAction.setShortcut("Ctrl+S")
fileMenu.addAction(saveAction)
saveAction.triggered.connect(self.save)
def save(self):
filePath, _ = QFileDialog.getSaveFileName(self.drawer, "Save Image", "",
"PNG(*.png);;JPEG(*.jpg *.jpeg);;All Files(*.*) ")
if filePath == "":
return
self.drawer.image_layer.save(filePath)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = Window()
window.show()
sys.exit(app.exec())
Note: there are only two lines that mimics the grid, I can draw it later, but for now I want the saved image to not include the grind lines.
You should paint the grid in the paintEvent, instead of continuously painting it onto the image.
def paintEvent(self, event):
painter = QPainter(self)
painter.drawImage(QPoint(), self.image_layer)
gridSize = 10
x = y = 0
width = self.width()
height = self.height()
while y <= height:
# draw horizontal lines
painter.drawLine(0, y, width, y)
y += gridSize
while x <= width:
# draw vertical lines
painter.drawLine(x, 0, x, height)
x += gridSize
I can add QWidget to QMainWindow and set its position to cursor position.
But every single time, I want to add new QWidget to QMainWindow. I don't maybe given codes add new QWidget but at canvas, I see just one QWidget. Here my codes:
from PyQt5.QtWidgets import QMainWindow, QApplication, QMenu, QMenuBar, QAction, QFileDialog, QWidget, QLabel
from PyQt5.QtGui import QIcon, QImage, QPainter, QPen, QBrush
from PyQt5.QtCore import Qt, QPoint
import sys
class Window(QMainWindow):
def __init__(self):
super().__init__()
title = "Paint Application"
top = 400
left = 400
width = 800
height = 600
self.objStr = "berkayy"
self.count = 0
# icon = "icons/pain.png"
self.setAcceptDrops(True)
self.setWindowTitle(title)
self.setGeometry(top, left, width, height)
# self.setWindowIcon(QIcon(icon))
self.image = QImage(self.size(), QImage.Format_RGB32)
self.image.fill(Qt.white)
self.drawing = False
self.brushSize = 2
self.brushColor = Qt.black
self.lastPoint = QPoint()
mainMenu = self.menuBar()
fileMenu = mainMenu.addMenu("File")
brushSize = mainMenu.addMenu("Brush Size")
brushColor = mainMenu.addMenu("Brush Color")
saveAction = QAction(QIcon("icons/save.png"), "Save",self)
saveAction.setShortcut("Ctrl+S")
fileMenu.addAction(saveAction)
saveAction.triggered.connect(self.save)
clearAction = QAction(QIcon("icons/clear.png"), "Clear", self)
clearAction.setShortcut("Ctrl+C")
fileMenu.addAction(clearAction)
clearAction.triggered.connect(self.clear)
threepxAction = QAction( QIcon("icons/threepx.png"), "3px", self)
brushSize.addAction(threepxAction)
threepxAction.triggered.connect(self.threePixel)
fivepxAction = QAction(QIcon("icons/fivepx.png"), "5px", self)
brushSize.addAction(fivepxAction)
fivepxAction.triggered.connect(self.fivePixel)
sevenpxAction = QAction(QIcon("icons/sevenpx.png"),"7px", self)
brushSize.addAction(sevenpxAction)
sevenpxAction.triggered.connect(self.sevenPixel)
ninepxAction = QAction(QIcon("icons/ninepx.png"), "9px", self)
brushSize.addAction(ninepxAction)
ninepxAction.triggered.connect(self.ninePixel)
blackAction = QAction(QIcon("icons/black.png"), "Black", self)
blackAction.setShortcut("Ctrl+B")
brushColor.addAction(blackAction)
blackAction.triggered.connect(self.blackColor)
whitekAction = QAction(QIcon("icons/white.png"), "White", self)
whitekAction.setShortcut("Ctrl+W")
brushColor.addAction(whitekAction)
whitekAction.triggered.connect(self.whiteColor)
redAction = QAction(QIcon("icons/red.png"), "Red", self)
redAction.setShortcut("Ctrl+R")
brushColor.addAction(redAction)
redAction.triggered.connect(self.redColor)
greenAction = QAction(QIcon("icons/green.png"), "Green", self)
greenAction.setShortcut("Ctrl+G")
brushColor.addAction(greenAction)
greenAction.triggered.connect(self.greenColor)
yellowAction = QAction(QIcon("icons/yellow.png"), "Yellow", self)
yellowAction.setShortcut("Ctrl+Y")
brushColor.addAction(yellowAction)
yellowAction.triggered.connect(self.yellowColor)
def rectangle(self, e, pos):
print(pos)
painter = QPainter(self)
painter.setPen(QPen(Qt.black, 5, Qt.SolidLine))
painter.setBrush(QBrush(Qt.green, Qt.DiagCrossPattern))
painter.drawRect(100, 15, 400, 200)
def mousePressEvent(self, event):
if event.button() == Qt.LeftButton:
self.drawing = True
self.lastPoint = event.pos()
#print(self.lastPoint)
def contextMenuEvent(self, event):
contextMenu = QMenu(self)
newAct = contextMenu.addAction("New")
openAct = contextMenu.addAction("Open")
closeAct = contextMenu.addAction("Close")
action = contextMenu.exec_(self.mapToGlobal(event.pos()))
if action == closeAct:
self.close()
elif action == openAct:
self.berkay(event.pos())
def mouseMoveEvent(self, event):
if(event.buttons() & Qt.LeftButton) & self.drawing:
painter = QPainter(self.image)
painter.setPen(QPen(self.brushColor, self.brushSize, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
painter.drawLine(self.lastPoint, event.pos())
self.lastPoint = event.pos()
self.update()
def berkay(self, pos):
wid = QWidget(self)
btn = QLabel(wid)
btn.setText("skjdf")
btn.setObjectName(self.objStr + str(self.count) )
btn.move(pos)
self.setCentralWidget(wid)
self.count += 1
# btn.setDragEnabled(True)
print(btn.objectName())
# self.show()
def mouseReleaseEvent(self, event):
if event.button() == Qt.LeftButton:
self.drawing = False
def paintEvent(self, event):
canvasPainter = QPainter(self)
canvasPainter.drawImage(self.rect(),self.image, self.image.rect() )
def save(self):
filePath, _ = QFileDialog.getSaveFileName(self, "Save Image", "", "PNG(*.png);;JPEG(*.jpg *.jpeg);;All Files(*.*) ")
if filePath == "":
return
self.image.save(filePath)
def clear(self):
self.image.fill(Qt.white)
self.update()
def threePixel(self):
self.brushSize = 3
def fivePixel(self):
self.brushSize = 5
def sevenPixel(self):
self.brushSize = 7
def ninePixel(self):
self.brushSize = 9
def blackColor(self):
self.brushColor = Qt.black
def whiteColor(self):
self.brushColor = Qt.white
def redColor(self):
self.brushColor = Qt.red
def greenColor(self):
self.brushColor = Qt.green
def yellowColor(self):
self.brushColor = Qt.yellow
if __name__ == "__main__":
app = QApplication(sys.argv)
window = Window()
window.show()
app.exec()
I want to create new QWidget when user clicked context menu item every single time.
A QMainWindow can have only one central widget. So, adding the new QLabel as central widget will remove the previous. That's why you can see only the last label.
Create a single widget and define it as central widget. Then, add the label as child of the central widget:
class Window(QMainWindow):
def __init__(self):
super().__init__()
self.area = QWidget(self)
self.setCentralWidget(self.area)
def berkay(self, pos):
btn = QLabel("BOOH", self.area)
btn.move(self.area.mapFromParent(pos)) # Map the pos in the coord system of self.area
btn.show()
First, for every single widget, store x and y value in a list. After that, adding new and current widgets to window central widget.
Edit
We do not need store widget x and y, anymore.
Thank you Romha for optimisation suggestion.
import sys
from PyQt5.QtWidgets import QMainWindow, QMenu, QApplication, QWidget, QPushButton, qApp
from PyQt5 import QtGui, QtCore
from PyQt5.QtCore import Qt
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.area = QWidget(self)
self.setCentralWidget(self.area)
self.initUI()
def initUI(self):
self.setGeometry(300, 300, 300, 200)
self.setWindowTitle('Context menu')
self.setStyleSheet("QMainWindow {background: 'white';}")
self.show()
def contextMenuEvent(self, event):
cmenu = QMenu(self)
addBtnAct = cmenu.addAction("Add Button")
quitAct = cmenu.addAction("Quit")
action = cmenu.exec_(self.mapToGlobal(event.pos()))
if action == quitAct:
qApp.quit()
elif action == addBtnAct:
self.addLabel(event.pos())
def addLabel(self, pos):
btn = QLabel("BOOH", self.area)
btn.move(self.area.mapFromParent(pos)) # Map the pos in the coord system of self.area
btn.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
Here is my code:
import sys
from PyQt5.QtWidgets import (QApplication, QLabel, QWidget)
from PyQt5.QtGui import QPainter, QColor, QPen
from PyQt5.QtCore import Qt
class MouseTracker(QWidget):
distance_from_center = 0
def __init__(self):
super().__init__()
self.initUI()
self.setMouseTracking(True)
def initUI(self):
self.setGeometry(200, 200, 1000, 500)
self.setWindowTitle('Mouse Tracker')
self.label = QLabel(self)
self.label.resize(500, 40)
self.show()
def mouseMoveEvent(self, event):
distance_from_center = round(((event.y() - 250)**2 + (event.x() - 500)**2)**0.5)
self.label.setText('Coordinates: ( %d : %d )' % (event.x(), event.y()) + "Distance from center: " + str(distance_from_center))
q = QPainter() #Painting the line
q.begin(self)
q.drawLine(event.x(), event.y(), 250, 500)
q.end()
def drawPoints(self, qp, x, y):
qp.setPen(Qt.red)
qp.drawPoint(x, y)
app = QApplication(sys.argv)
ex = MouseTracker()
sys.exit(app.exec_())
What I'm trying to do is paint a simple line from the position of the mouse to the middle of the widget using this:
q = QPainter() #Painting the line
q.begin(self)
q.drawLine(event.x(), event.y(), 250, 500)
q.end()
But when I run it, no line is visible. What do I need to do?
You must implement the function QPaintEvent, in this function you must draw the line, in addition you must call the function update() to update the drawing.
import sys
from PyQt5.QtWidgets import (QApplication, QLabel, QWidget)
from PyQt5.QtGui import QPainter, QColor, QPen
from PyQt5.QtCore import Qt
class MouseTracker(QWidget):
distance_from_center = 0
def __init__(self):
super().__init__()
self.initUI()
self.setMouseTracking(True)
def initUI(self):
self.setGeometry(200, 200, 1000, 500)
self.setWindowTitle('Mouse Tracker')
self.label = QLabel(self)
self.label.resize(500, 40)
self.show()
self.pos = None
def mouseMoveEvent(self, event):
distance_from_center = round(((event.y() - 250)**2 + (event.x() - 500)**2)**0.5)
self.label.setText('Coordinates: ( %d : %d )' % (event.x(), event.y()) + "Distance from center: " + str(distance_from_center))
self.pos = event.pos()
self.update()
def paintEvent(self, event):
if self.pos:
q = QPainter(self)
q.drawLine(self.pos.x(), self.pos.y(), 500, 250)
app = QApplication(sys.argv)
ex = MouseTracker()
sys.exit(app.exec_())
Output:
You can only use a QPainter inside the paintEvent method. So one way to fix is to record the x and y coordinates inside the class and update the root widget. This then calls paintEvent and you will see the line.
example
import sys
from PyQt5.QtWidgets import QApplication, QLabel, QWidget
from PyQt5.QtGui import QPainter
from PyQt5.QtCore import Qt
class MouseTracker(QWidget):
distance_from_center = 0
def __init__(self):
super().__init__()
self.initUI()
self.setMouseTracking(True)
self.x = -1
self.y = -1
def initUI(self):
self.setGeometry(200, 200, 1000, 500)
self.setWindowTitle('Mouse Tracker')
self.label = QLabel(self)
self.label.resize(500, 40)
self.show()
def paintEvent(self, e):
if not (self.x == -1 or self.y == -1):
q = QPainter() #Painting the line
q.begin(self)
q.drawLine(self.x, self.y, 250, 500)
q.end()
def mouseMoveEvent(self, event):
distance_from_center = round(((event.y() - 250)**2 + (event.x() - 500)**2)**0.5)
self.label.setText('Coordinates: ( %d : %d )' % (event.x(), event.y()) + "Distance from center: " + str(distance_from_center))
self.x = event.x()
self.y = event.y()
self.update()
def drawPoints(self, qp, x, y):
qp.setPen(Qt.red)
qp.drawPoint(x, y)
app = QApplication(sys.argv)
ex = MouseTracker()
sys.exit(app.exec_())
I wasn't sure about how self.x and self.y would be set initially. The -1 and the check in the paintEvent feels a bit hacky, but at least it paints.
For the previous answer, I tried it under Python3.7 and PyQt5. The result was program crash
'Process finished with exit code -1073740791 (0xC0000409)'.
And in the comments, there were someone else also mentioned the crash.
I find the solution to this crash:
self.x and self.y must be initialized before the calling of self.show()
So I simply modified the code to as follows:
def initUI(self):
self.setGeometry(200, 200, 1000, 500)
self.setWindowTitle('Mouse Tracker')
self.label = QLabel(self)
self.label.resize(500, 40)
self.x = 100
self.y = 100
self.show()
I'm trying to re-implement the scribble demo app for multiple layers of images. I am struggling to draw into the pixmap within the scene as the Painter complains that is being destroyed to early.
QPaintDevice: Cannot destroy paint device that is being painted
Could you please help me fix my code such that you can draw on to the roilayer pixmap with the red pen and that this layer starts transparent.
#!/usr/bin/python3
import sys
import os
from PyQt5.QtWidgets import QApplication, QGraphicsView, QGraphicsScene, QGraphicsPixmapItem
from PyQt5.QtGui import QPixmap, QImage, QPainter, QPen
from PyQt5.QtCore import Qt, QRect
class Main(QGraphicsView):
def __init__(self):
super().__init__()
self.setWindowTitle("Scribble with layers")
self.scene = QGraphicsScene()
self.setScene(self.scene)
self.image = QImage('sample/test.bmp')
self.imlayer = QGraphicsPixmapItem(QPixmap.fromImage(self.image))
self.roilayer = QGraphicsPixmapItem(QPixmap(self.image.size()))
self.addlayer(self.imlayer)
self.addlayer(self.roilayer)
self.drawing = False
self.lastPoint = None
self.pencolour = Qt.red
self.penwidth = 2
self.show()
def addlayer(self, layer):
self.scene.addItem(layer)
self.updateviewer()
def updateviewer(self):
self.fitInView(self.sceneRect(), Qt.KeepAspectRatio)
def mousePressEvent(self, event):
# print(event.modifiers())
if event.button() == Qt.LeftButton:
self.lastPoint = event.pos()
self.drawing = True
def mouseMoveEvent(self, event):
if (event.buttons() & Qt.LeftButton) and self.drawing:
self.drawlineto(event.pos())
def mouseReleaseEvent(self, event):
if event.button() == Qt.LeftButton and self.drawing:
self.drawlineto(event.pos())
self.drawing = False
def drawlineto(self, position):
pixmap = self.roilayer.pixmap()
painter = QPainter(pixmap)
painter.setPen(QPen(self.pencolour, self.penwidth, Qt.SolidLine,
Qt.RoundCap, Qt.RoundJoin))
painter.drawLine(self.lastPoint, position)
self.imlayer.setPixmap(pixmap)
self.modified = True
rad = self.penwidth / 2 + 2
self.update(QRect(self.lastPoint, position).normalized().adjusted(-rad, -rad, +rad, +rad))
self.lastPoint = position
if __name__ == '__main__':
app = QApplication([])
main = Main()
sys.exit(app.exec_())
I had the same problem. The solution is to do the following to this part of your code:
def drawlineto(self, position):
pixmap = self.roilayer.pixmap()
painter = QPainter()
painter.begin(pixmap)
painter.setPen(QPen(self.pencolour, self.penwidth, Qt.SolidLine,
Qt.RoundCap, Qt.RoundJoin))
painter.drawLine(self.lastPoint, position)
painter.end()
self.imlayer.setPixmap(pixmap)
self.modified = True