水平排列QGraphicsView中QTextEdit鼠标选中文本异常问题

问题表现 #

同一布局内共放置3个QGraphicsView控件：

• 当控件为垂直排列（orientation参数设为0）时，鼠标拖动选中QTextEdit内文本的功能无任何异常
• 当控件为水平排列（orientation参数设为1）时，文本选择功能失效：即便视图是水平排布的，用户仍然需要垂直拖动鼠标才能选中文本，水平拖动无法触发符合直觉的选区更新

已排查到的逻辑 #

鼠标按下事件触发时，初始坐标以QTextEdit自身坐标系为基准判定；鼠标移动事件触发时，会以鼠标按下的位置作为锚点计算当前鼠标点位更新选区；鼠标释放事件的坐标判定逻辑与上述逻辑一致。

待解决疑问 #

是否有方法实现水平排布场景下自然流畅的鼠标选中文本效果？还是Qt本身仅支持垂直方向拖动的鼠标文本选择逻辑？

复现代码 #

from PySide6.QtWidgets import QApplication, QGraphicsView, QGraphicsScene, QGraphicsProxyWidget, QTextEdit
from PySide6.QtGui import QTextDocument, QPageSize, QPainter, QBrush, QTextCharFormat, QTextOption
from PySide6.QtCore import Qt, Signal, QRect, QRectF, QEvent, QSize, QSizeF, QPointF


class MainGraphicsView(QGraphicsView):
    def __init__(self, parent=None):
        super(MainGraphicsView, self).__init__(parent)
        self._mainscene = MainGraphicsScene(1)
        self._mainscene._mainview = self
        self.setScene(self._mainscene)          


class MainGraphicsScene(QGraphicsScene):  
    def __init__(self, orientation = 1, parent=None):
        super(MainGraphicsScene, self).__init__(parent)
        
        if orientation == 0:
            self.rootView = TextGraphicsView()        
            self.rootView.main_scene = self
            self.root_proxywidget = self.addWidget(self.rootView)
            self.rootView.setSceneRect(0, 0, self.document()._pageWidth, self.document()._pageHeight)

            self.secondaryView = SecondaryTextGraphicsView(2, self.rootView.scene())
            self.secondaryView.setSceneRect(0, self.document()._pageHeight, self.document()._pageWidth, self.document()._pageHeight)
            self.secondary_proxywidget = self.addWidget(self.secondaryView)
            self.secondary_proxywidget.setPos(0, self.document()._pageHeight)

            self.thirdView = SecondaryTextGraphicsView(3, self.rootView.scene())
            self.thirdView.setSceneRect(0, self.document()._pageHeight*2, self.document()._pageWidth, self.document()._pageHeight)
            self.third_proxywidget = self.addWidget(self.thirdView)
            self.third_proxywidget.setPos(0, self.document()._pageHeight*2)
            
        if orientation == 1:
            self.rootView = TextGraphicsView()        
            self.rootView.main_scene = self
            self.root_proxywidget = self.addWidget(self.rootView)
            self.rootView.setSceneRect(0, 0, self.document()._pageWidth, self.document()._pageHeight)

            self.secondaryView = SecondaryTextGraphicsView(2, self.rootView.scene())
            self.secondaryView.setSceneRect(0, self.document()._pageHeight, self.document()._pageWidth, self.document()._pageHeight)
            self.secondary_proxywidget = self.addWidget(self.secondaryView)
            self.secondary_proxywidget.setPos(self.document()._pageWidth, 0)

            self.thirdView = SecondaryTextGraphicsView(3, self.rootView.scene())
            self.thirdView.setSceneRect(0, self.document()._pageHeight*2, self.document()._pageWidth, self.document()._pageHeight)
            self.third_proxywidget = self.addWidget(self.thirdView)
            self.third_proxywidget.setPos(self.document()._pageWidth*2, 0)

        self.setBackgroundBrush(QBrush(Qt.gray))      
   
    def view(self):
        return self._mainview

    def textedit(self):
        return self.document().parent()

    def document(self):
        return self.rootView.document()
    
    
class TextGraphicsView(QGraphicsView):
    def __init__(self,  parent=None):
        super().__init__(parent)
        self.page = 1
        self.initScene()

    def mousePressEvent(self, event):
        SecondaryTextGraphicsView.selectedPage = self.page
        return QGraphicsView.mousePressEvent(self, event)

    def initScene(self):
        self.common_scene = TextGraphicsScene()
        self.common_scene.root_view = self
        self.setScene(self.common_scene)
        self.setSceneRect(0, self.document()._pageHeight*(self.page -1), self.document()._pageWidth, self.document()._pageHeight)
        self.resize(int(self.document()._pageWidth), int(self.document()._pageHeight))
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)

    def view(self):
        return self.main_scene._mainview
    
    def textedit(self):
        return self.common_scene.textedit
    
    def document(self):
        return self.common_scene.textedit.document()       


class SecondaryTextGraphicsView(QGraphicsView):
    def __init__(self, page, scene, parent=None):
        super().__init__(scene, parent)
        self.page = page
        self.initScene()
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)    

    def initScene(self):
        self.setSceneRect(0, self.document()._pageHeight*(self.page-1), self.document()._pageWidth, self.document()._pageHeight)
        self.resize(int(self.document()._pageWidth), int(self.document()._pageHeight))

    def view(self):
        return self.scene().root_view.view()

    def textedit(self):
        return self.scene().textedit()
    
    def document(self):
        return self.scene().textedit.document()


class TextGraphicsScene(QGraphicsScene):
    def __init__(self, parent=None):
        super().__init__(parent)        
        self.textedit = TextEdit(scene=self)        
        self.addWidget(self.textedit)

    def view(self):
        return self.root_view

    def document(self):
        return self.textedit.document()     
    

class TextEdit(QTextEdit):
    def __init__(self,  scene, parent=None):
        super().__init__(parent)
        self.setAttribute(Qt.WA_InputMethodEnabled, True)
        self.setMouseTracking(False)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)       
        self.scene = scene
        self.setDocument(TextDocument(parent=self))
        self.setWordWrapMode(QTextOption.WrapAtWordBoundaryOrAnywhere)
        self.setLineWrapMode(self.LineWrapMode.FixedPixelWidth)
        self.setLineWrapColumnOrWidth(self.document()._pageWidth)
        self.setAttribute(Qt.WA_InputMethodEnabled, True)
        self.setInputMethodHints(Qt.ImhMultiLine)
        self.resize(self.document()._pageSize.toSize().width(), self.document()._pageSize.toSize().height()*3)
        self.setPlainText("Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        \Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
                        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. \
                        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. \
                        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. \
                        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.")

    def mouseMoveEvent(self, event):
        print(event.position())
        return QTextEdit.mouseMoveEvent(self, event)
    
    def view(self):
        return self.scene.root_view
    
    def pageSize(self):
        return self.document()._pageSize    
        

class TextDocument(QTextDocument):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._pageSize = QPageSize.size(QPageSize.A4, QPageSize.Point)       
        self._pageHeight = self._pageSize.height()
        self._pageWidth  = self._pageSize.width()
        self.setDocumentMargin(30.5) 


def main():
    import sys
    app = QApplication([]) if QApplication.instance() is None else QApplication.instance()
    m = MainGraphicsView()
    m.show()
    sys.exit(app.exec())


if __name__ == "__main__":
    main()

内容的提问来源于stack exchange，提问作者Haru