Disable auto-scrolling in QPlainTextEdit

[lukass]

Hello.
I want append html to the end of document without scroll to the bottom in QPlainTextEdit.

One way I was saving and restoring scrollbar position, but this generate flicker of scrollbar.
How can I disable auto scrolling to the end of document in appendHtml(), when vertical slider is on maximum position?

[high_flyer]

you can set the scroll policy via setVerticalScrollBarPolicy().

[lukass]

you can set the scroll policy via setVerticalScrollBarPolicy().

Thanks, but this not work:

setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
appendHtml(html);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);

setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
appendHtml(html);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);

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This code doesn't disable scrolling of text. Moreover, scrolling to bottom always.

I found(probably good for me) solution for disable scrolling:

...
volatile bool lock = false;
...

...
volatile bool lock = false;
...

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override virtual function scrollContentsBy of QPlainTextEdit:

void my_plaintextedit::scrollContentsBy(int dx, int dy)
{
  if(lock == false)
    QPlainTextEdit::scrollContentsBy(dx, dy);
}

void my_plaintextedit::scrollContentsBy(int dx, int dy)
{
  if(lock == false)
    QPlainTextEdit::scrollContentsBy(dx, dy);
}

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and:

void my_plaintextedit::append_line(const QString & html)
{
  if(mouse_press) //is mouse button pressed in viewport of QPlainTextEdit?
    lock = true;
  appendHtml(html);
  lock = false;
}

void my_plaintextedit::append_line(const QString & html)
{
  if(mouse_press) //is mouse button pressed in viewport of QPlainTextEdit?
    lock = true;
  appendHtml(html);
  lock = false;
}

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