Details
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Bug
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Resolution: Unresolved
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P3: Somewhat important
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None
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5.8.0
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None
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Windows 10 Qt 5.6.0 ~ 5.0.2
MacOS 10.13 High Sierra xCode 9.0 on a Retina iMac
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macOS
Description
Hello,
I'm working on a nodal system in a QGraphicsView that I can zoom in/out.
When I paint 1px lines (fully opaque) on my nodes, it's nicely displayed but if I start zooming out, The opacity level looks like it's changing since I can see through some lines and see lines below.
Here is the link to the topic on the forum :
https://forum.qt.io/topic/84154/painter-drawline-overlapping-opacity-problems-with-100-opaque-pen/26
Here is some code to re-create the problem :
from PySide2 import QtGui, QtCore, QtWidgets class TestView(QtWidgets.QGraphicsView): def __init__(self, parent=None): super(TestView, self).__init__(parent) self.setOptimizationFlag(QtWidgets.QGraphicsView.DontAdjustForAntialiasing) self.setRenderHint(QtGui.QPainter.Antialiasing, False) self.setRenderHint(QtGui.QPainter.HighQualityAntialiasing, False) self.setRenderHint(QtGui.QPainter.NonCosmeticDefaultPen, False) self.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate) self.setTransformationAnchor(QtWidgets.QGraphicsView.AnchorUnderMouse) self.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff) self.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff) def wheelEvent(self, event): self.setTransformationAnchor(QtWidgets.QGraphicsView.AnchorUnderMouse) inFactor = 1.15 outFactor = 1 / inFactor if event.delta() > 0: zoomFactor = inFactor else: zoomFactor = outFactor self.scale(zoomFactor, zoomFactor) class TestItem(QtWidgets.QGraphicsItem): def __init__(self): super(TestItem, self).__init__() def boundingRect(self): return QtCore.QRect(0, 0, 200, 400) def shape(self): path = QtGui.QPainterPath() path.addRect(self.boundingRect()) return path def paint(self, painter, option, widget): brush = QtGui.QBrush(QtGui.QColor(70, 70, 70, 255)) painter.setBrush(brush) painter.drawRoundedRect(0, 0, 200, 400, 20, 20) pen = QtGui.QPen(QtGui.QColor(200, 200, 200, 255)) pen.setWidth(1) painter.setPen(pen) painter.drawLine(50, 50, 50, 300) painter.drawLine(50, 80, 50, 200) painter.drawLine(50, 80, 150, 80) view = TestView() scene = QtWidgets.QGraphicsScene() view.setScene(scene) item = TestItem() scene.addItem(item) view.show()
thx
