QTextEdit::append should have a QColor or QTextCharFormat parameter

[Megamouse]

Hi,

I stumbled upon a use case where i would like to add text in a new color at the end of my document without losing or repainting my selection or scrolling in case of isBottom.

This is basically what append does. But if i wanna change my new textcolor with setTextColor I repaint my selection.

What is the best way of doing this? Or is it simply unimplemented?

thx Megamouse

[Megamouse]

To be precise...
It would be necessary to add the color part here (see the comments):

void QTextEdit::append(const QString &text) // add param: const QColor& color
{
    Q_D(QTextEdit);
    const bool atBottom = isReadOnly() ?  d->verticalOffset() >= d->vbar->maximum() :
            d->control->textCursor().atEnd();
    d->control->append(text); // add color
    if (atBottom)
        d->vbar->setValue(d->vbar->maximum());
}

void QWidgetTextControlPrivate::append(const QString &text, Qt::TextFormat format)
{
    QTextCursor tmp(doc);
    tmp.beginEditBlock();
    tmp.movePosition(QTextCursor::End);
	
    // Old code:
    //if (!doc->isEmpty())
    //    tmp.insertBlock(cursor.blockFormat(), cursor.charFormat());
    //else
    //    tmp.setCharFormat(cursor.charFormat());
	
    // New code:
    QTextCharFormat newCharFormat = cursor.charFormat();
    if (color.isValid())
        newCharFormat.setForeground(color);
    if (!doc->isEmpty())
        tmp.insertBlock(cursor.blockFormat(), newCharFormat);
    else
        tmp.setCharFormat(newCharFormat);
	
    // preserve the char format
    QTextCharFormat oldCharFormat = cursor.charFormat();
#ifndef QT_NO_TEXTHTMLPARSER
    if (format == Qt::RichText || (format == Qt::AutoText && Qt::mightBeRichText(text))) {
        tmp.insertHtml(text);
    } else {
        tmp.insertText(text);
    }
#else
    Q_UNUSED(format);
    tmp.insertText(text);
#endif // QT_NO_TEXTHTMLPARSER
    if (!cursor.hasSelection())
        cursor.setCharFormat(oldCharFormat);
    tmp.endEditBlock();
}

[Megamouse]

On another note: The append function should get a flag that skips the insertBlock

[SGaist]

Hi,

Can you explain what your use case is ?

[Megamouse]

@SGaist a log that has different colors depending on error types etc.

[SGaist]

Looks rather like a job for QSyntaxHighlighter.

[Megamouse]

I am not sure but I get the feeling the Syntaxhighlighter is too slow for a log

[mrjj]

@Megamouse
Hi
Just as note. I found QTextEdit with append too slow with huge logs
files and switch to a listView with a delegate.

[SGaist]

@Megamouse said in QTextEdit::append should have a QColor or QTextCharFormat parameter:

I am not sure but I get the feeling the Syntaxhighlighter is too slow for a log

That's one crucial detail you forgot to say in your problem description. @mrjj is right here, to show logs like that, the model/view architecture will work better.

[VRonin]

It you stick with QTextEdit the QTextCursor interface is public so you can use QTextEdit::cursor() and do exactly what QWidgetTextControlPrivate::append does changing what you need