How can I set the alignment of the arrows on a QTreeWidgetItem

Question

I want these TreeWidget Arrows to align with the top of the TreeWidgetItem.

I've got a QtWidgets.QTreeWidget(), and have created a custom QtWidgets.QTreeWidgetItem().

I then set a custom Item widget self.tree_widget.setItemWidget(self.tree_widget_item, 0, self.main_widget)

As a result the decorator / arrow positions itself evenly in the center of the geometry, however I want it to be aligned at the top.

I've been looking into setting the alignment for this, but am not 100% sure where to set it, or if I need to set it through a style sheet. If I'm unable to move this I can create a custom widget to replace the decorator, and hide the default ones, but I'd prefer to use what's here if possible. Any ideas? Thanks!

Answer 1

You could reimplement QTreeView.drawBranches and set a smaller height to the QRect used to draw each branch. Simply using the width is a good value if the arrows are symmetrical.

import sys
from PySide2.QtWidgets import *

class Tree(QTreeWidget):

    def drawBranches(self, painter, rect, index):
        rect.setHeight(rect.width())
        super().drawBranches(painter, rect, index)
        

if __name__ == '__main__':
    app = QApplication(sys.argv)
    tree = Tree()
    for i in range(5):
        item = QTreeWidgetItem([f'Item {i}\n\n'])
        item.addChild(QTreeWidgetItem([f'Child {i}']))
        tree.addTopLevelItem(item)
    tree.show()
    sys.exit(app.exec_())

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