QScrollArea with a QLabel isn't auto scrolling



  • It's a bit long so please bear with me.

    I have a QLabel with text that's wider than the window size.
    The QLabel is inside a horizontal QScrollArea:

    scrollArea->setWidget(label);
    scrollArea->setFixedSize(WINDOW_WIDTH , BUTTON_HEIGHT);
    

    I navigate through letters in the QLabel by the keyboard arrow keys, setting selection on each letter by QLabel::setSelection().
    For example say I have the text abcdefghijklmno|pqrstuvwxyz . The pipe (|) indicates the end of the window - it's not really there. So currently only the letters {a...o} are visible. I start by setting selection on the letter a. Then I press the right arrow key and set selection on the letter b, and so on...
    Say I reached letter o :
    abcdefghijklmno**|pqrstuvwxyz**
    I expect the scrollArea to scroll right on the next click. But it doesn't. Namely when the letter p is selected, I need the scrollArea to scroll to make it visible.

    I tried ensureVisible() but it's not working for me - the scrollArea won't scroll whatever I passed to ensureVisible(). For example I tried ensureVisible(WINDOW_SIZE+20 , 0) or ensureVisible(20 , 0) and neither of them worked. I guess ensureVisible() is not what I need.

    Of course I can count letters and when I reach say the 14th letter, I scroll it. But that's not good because say I scroll to letter 20, then go back to 13 - the next right click shouldn't scroll, but it would.

    Anyway, what I'm currently doing is keeping a counter for the font width up until the selected letter. I update it on every right/left click (right click: increment counter by width , left click: decrement counter by width) - and using that I decide when to scroll. It's good but it's not perfect.
    Any other ideas? Preferably something neat and automatic, not a workaround.

    Thanks!


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