How to make paintEvent work when subclassing QRubberBand? - qt

Question

Currently, I'm using PySide to do image cropping under Ubuntu 14.04 LTS. I came across the answer in this post, which describes a rough idea of how to do image cropping. Now I'd like to change the width and color of the cropping rectangle. Following this, I understand I should create a class which subclasses QRubberBand and overrides the paintEvent method. So I got the python code at the bottom. As you can see, I did pen.setWidth(5) in paintEvent. However, when I do image cropping, the line width does not change (seems to remain 1 as default). See the following red rectangle.
Please help. Thanks!
import sys
from PyQt4 import QtGui, QtCore
class MyRubberBand(QtGui.QRubberBand):
def __init__(self, QRubberBand_Shape, QWidget_parent=None):
super(MyRubberBand, self).__init__(QRubberBand_Shape, QWidget_parent)
palette = QtGui.QPalette()
palette.setBrush(QtGui.QPalette.WindowText, QtGui.QBrush(QtCore.Qt.red))
self.setPalette(palette)
def paintEvent(self, QPaintEvent):
painter = QtGui.QStylePainter(self)
# painter.begin(self)
pen = QtGui.QPen()
# pen.setStyle(QtCore.Qt.SolidLine)
# pen.setColor(QtGui.QColor(QtCore.Qt.red))
pen.setWidth(5)
painter.setPen(pen)
option = QtGui.QStyleOptionFocusRect()
option.initFrom(self)
painter.drawControl(QtGui.QStyle.CE_FocusFrame, option)
class QExampleLabel (QtGui.QLabel):
def __init__(self, parentQWidget = None):
super(QExampleLabel, self).__init__(parentQWidget)
self.initUI()
def initUI (self):
self.setPixmap(QtGui.QPixmap('images/3.png'))
self.currentQRubberBand = MyRubberBand(QtGui.QRubberBand.Rectangle, self)
def mousePressEvent (self, eventQMouseEvent):
print 'mouse pressed'
self.originQPoint = eventQMouseEvent.pos()
self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, QtCore.QSize()))
self.currentQRubberBand.show()
def mouseMoveEvent (self, eventQMouseEvent):
self.currentQRubberBand.setGeometry(QtCore.QRect(self.originQPoint, eventQMouseEvent.pos()).normalized())
def mouseReleaseEvent (self, eventQMouseEvent):
print 'mouse released'
# self.currentQRubberBand.hide()
currentQRect = self.currentQRubberBand.geometry()
# self.currentQRubberBand.deleteLater()
cropQPixmap = self.pixmap().copy(currentQRect)
cropQPixmap.save('output.png')
if __name__ == '__main__':
myQApplication = QtGui.QApplication(sys.argv)
myQExampleLabel = QExampleLabel()
myQExampleLabel.show()
sys.exit(myQApplication.exec_())

Answer 1

I know this question is old but I was recently trying to do the same thing and seen this so I want to post some code for anyone else who might come across this as well.
Your code with updated paintEvent.
PySide2:
import sys
from PySide2.QtCore import Qt, QRect, QSize
from PySide2.QtGui import QColor, QPen, QBrush, QPixmap, QPainter, QPalette
from PySide2.QtWidgets import QApplication, QLabel, QRubberBand
class MyRubberBand(QRubberBand):
def __init__(self, QRubberBand_Shape, QWidget_parent=None):
super(MyRubberBand, self).__init__(QRubberBand_Shape, QWidget_parent)
palette = QPalette()
palette.setBrush(QPalette.WindowText, QBrush(Qt.red))
self.setPalette(palette)
def paintEvent(self, QPaintEvent):
###QRubberBand with black border and transparent background###
painter = QPainter(self)
###Border Color with width set at 6###
pen_color = QColor(0, 0, 0, 255)
painter.setPen(QPen(pen_color, 6))
###Transparent background###
brush_color = QColor(Qt.transparent)
###Or to use solid background color###
# brush_color = QColor(Qt.red)
painter.setBrush(QBrush(brush_color))
painter.drawRect(QPaintEvent.rect())
class QExampleLabel (QLabel):
def __init__(self, parentQWidget = None):
super(QExampleLabel, self).__init__(parentQWidget)
self.initUI()
def initUI (self):
self.setPixmap(QPixmap('images/3.png'))
self.currentQRubberBand = MyRubberBand(QRubberBand.Rectangle, self)
def mousePressEvent (self, eventQMouseEvent):
print('mouse pressed')
self.originQPoint = eventQMouseEvent.pos()
self.currentQRubberBand.setGeometry(QRect(self.originQPoint, QSize()))
self.currentQRubberBand.show()
def mouseMoveEvent (self, eventQMouseEvent):
self.currentQRubberBand.setGeometry(QRect(self.originQPoint, eventQMouseEvent.pos()).normalized())
def mouseReleaseEvent (self, eventQMouseEvent):
print('mouse released')
# self.currentQRubberBand.hide()
currentQRect = self.currentQRubberBand.geometry()
# self.currentQRubberBand.deleteLater()
cropQPixmap = self.pixmap().copy(currentQRect)
cropQPixmap.save('output.png')
if __name__ == '__main__':
myQApplication = QApplication(sys.argv)
myQExampleLabel = QExampleLabel()
myQExampleLabel.resize(800, 600)
myQExampleLabel.show()
sys.exit(myQApplication.exec_())
PyQt5:
import sys
from PyQt5.QtCore import Qt, QRect, QSize
from PyQt5.QtGui import QColor, QPen, QBrush, QPixmap, QPainter, QPalette
from PyQt5.QtWidgets import QApplication, QLabel, QRubberBand
class MyRubberBand(QRubberBand):
def __init__(self, QRubberBand_Shape, QWidget_parent=None):
super(MyRubberBand, self).__init__(QRubberBand_Shape, QWidget_parent)
palette = QPalette()
palette.setBrush(QPalette.WindowText, QBrush(Qt.red))
self.setPalette(palette)
def paintEvent(self, QPaintEvent):
###QRubberBand with black border and transparent background###
painter = QPainter(self)
###Border Color with width set at 6###
pen_color = QColor(0, 0, 0, 255)
painter.setPen(QPen(pen_color, 6))
###Transparent background###
brush_color = QColor(Qt.transparent)
###Or to use solid background color###
# brush_color = QColor(Qt.red)
painter.setBrush(QBrush(brush_color))
painter.drawRect(QPaintEvent.rect())
class QExampleLabel (QLabel):
def __init__(self, parentQWidget = None):
super(QExampleLabel, self).__init__(parentQWidget)
self.initUI()
def initUI (self):
self.setPixmap(QPixmap('images/3.png'))
self.currentQRubberBand = MyRubberBand(QRubberBand.Rectangle, self)
def mousePressEvent (self, eventQMouseEvent):
print('mouse pressed')
self.originQPoint = eventQMouseEvent.pos()
self.currentQRubberBand.setGeometry(QRect(self.originQPoint, QSize()))
self.currentQRubberBand.show()
def mouseMoveEvent (self, eventQMouseEvent):
self.currentQRubberBand.setGeometry(QRect(self.originQPoint, eventQMouseEvent.pos()).normalized())
def mouseReleaseEvent (self, eventQMouseEvent):
print('mouse released')
# self.currentQRubberBand.hide()
currentQRect = self.currentQRubberBand.geometry()
# self.currentQRubberBand.deleteLater()
cropQPixmap = self.pixmap().copy(currentQRect)
cropQPixmap.save('output.png')
if __name__ == '__main__':
myQApplication = QApplication(sys.argv)
myQExampleLabel = QExampleLabel()
myQExampleLabel.resize(800, 600)
myQExampleLabel.show()
sys.exit(myQApplication.exec_())