如何在委托中为粗体文本重新实现sizeHint？ （QT）

Question

Short Version

Running resizeColumnsToContents works fine for regular text, but when I change text to bold, the columns are too narrow. How can I fix sizeHint in my custom delegate to take into account that my text is bold?

Details

I am using a custom delegate to make the text in a column bold. To do this, in the paint method of the delegate, in the column of interest I just run option.font.setWeight(QtGui.QFont.Bold) .

When resizing columns to contents, however, the column with bolded text is too narrow. I tried to reimplement sizeHint in the delegate as follows, but it yields columns that are the exact same size as the default implementation:

def sizeHint(self, option, index):
    fontMetrics = option.fontMetrics  
    if index.column() == 0:
        text = index.model().data(index)
        document = QtGui.QTextDocument(text)
        document.setDefaultFont(option.font)
        return QtCore.QSize(document.idealWidth(), fontMetrics.height())
    return QtGui.QStyledItemDelegate.sizeHint(self, option, index)         

So, how can I get the sizeHint to correctly identify the width of my emboldened font? It seems I am simply sending in plain text here.

Related Questions

QLabel sizehint is too small

Answer 1

Based on the comment by Pie_Jesu, I inserted option.font.setWeight(QtGui.QFont.Bold) before calculating the width. So sizeHint ends up as follows:

def sizeHint(self, option, index):
    fontMetrics = option.fontMetrics  
    if index.column() == 0:
        text = index.model().data(index)
        document = QtGui.QTextDocument(text)
        option.font.setWeight(QtGui.QFont.Bold) #new line
        document.setDefaultFont(option.font)
        return QtCore.QSize(document.idealWidth(), fontMetrics.height())
    return QtGui.QStyledItemDelegate.sizeHint(self, option, index)    

So, basically, whatever properties you set with the text in your paint function, one way to match that width within sizeHint would be to explicitly build in those same properties.

It works, but it seems like suspicious code reduplication to set the text properties twice, once in paint and then again in sizeHint . There should be a more modular way. That is, a way for sizeHint to directly read the formatting from the item being displayed.

Edit added later: that's pretty much how these things work. On the plus size, by using QTextDocument , you are only setting up a document, not attaching it to a QTextEdit for display, so there is actually not much overhead here.