QTextEdit HTML font issue

wazzdaman · 15 Jan 2023, 13:55

Hello,

I'd like to edit text loaded as HTML into QTextEdit and saved as HTML. I've noticed that font-family holds multiple font names - the last one is added when I change the font but only the first one is taken in account, the rest is ignored.
The output looks kinda weird:

<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0//EN\" \"http://www.w3.org/TR/REC-html40/strict.dtd\">\n
<html>
<head><meta name=\"qrichtext\" content=\"1\" /><style type=\"text/css\">\np, li { white-space: pre-wrap; }\n</style></head>
<body style=\" font-family:'Arial'; font-size:42pt; font-weight:400; font-style:normal;\">\n
<p style=\" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;\">
<span style=\" font-family:'Arial','Modern';\">Text </span>
<span style=\" font-family:'Arial','Bahnschrift Condensed';\">BAR</span></p></body></html>

Everything is shown as Arial text in this case. How can I fix this problem?

Here's my code (minus the UI/dtor part), using Qt5.15.6 on Windows 10:

#include <QColorDialog>
#include <QMenuBar>
#include <QPalette>

#include "texteditordialog.h"

TextEditorDialog::TextEditorDialog(const QString &text, QDialog *parent)
    : QDialog(parent, (QDialog().windowFlags() & ~Qt::WindowContextHelpButtonHint))
{
    createWidgets();
    createLayout();
    createConnections();
    setWindowModality(Qt::ApplicationModal);
    setWindowTitle(tr("Edit text"));
    loadTextDocument(text);
}

void TextEditorDialog::createConnections()
{
    connect(textEdit, &QTextEdit::selectionChanged, this, &TextEditorDialog::setFormatTools);
    connect(textEdit, &QTextEdit::cursorPositionChanged, this, &TextEditorDialog::setFormatTools);
    connect(undoAction, &QAction::triggered, textEdit, &QTextEdit::undo);
    connect(redoAction, &QAction::triggered, textEdit, &QTextEdit::redo);
    connect(cutAction, &QAction::triggered, textEdit, &QTextEdit::cut);
    connect(copyAction, &QAction::triggered, textEdit, &QTextEdit::copy);
    connect(pasteAction, &QAction::triggered, textEdit, &QTextEdit::paste);
    connect(selectAction, &QAction::triggered, textEdit, &QTextEdit::selectAll);
    connect(fontComboBox, &QFontComboBox::currentFontChanged, textEdit, &QTextEdit::setFontFamily);
    connect(fontSizeComboBox, QOverload<int>::of(&QComboBox::currentIndexChanged),
            [=](int index){
        textEdit->setFontPointSize(qreal(4+index));
    });
    connect(boldAction, &QAction::toggled, this,
            [=](bool status){
        textEdit->setFontWeight(status ? QFont::Bold : QFont::Normal);
    });
    connect(italicAction, &QAction::toggled, textEdit, &QTextEdit::setFontItalic);
    connect(underlineAction, &QAction::toggled, textEdit, &QTextEdit::setFontUnderline);
    connect(fontColor, &ColorLabel::clicked, this,
            [=](){
        QColorDialog dialog;
        dialog.adjustSize();
        connect(&dialog, &QColorDialog::colorSelected, this, &TextEditorDialog::slotChangeFontColor);
        dialog.exec();
    });
    connect(backgroundColor, &ColorLabel::clicked, this,
            [=](){
        QColorDialog dialog;
        dialog.adjustSize();
        connect(&dialog, &QColorDialog::colorSelected, this, &TextEditorDialog::slotChangeBackgroundColor);
        dialog.exec();
    });
    connect(alignLAction, &QAction::triggered, this,
            [=](){
        textEdit->setAlignment(Qt::AlignLeft);
    });
    connect(alignCAction, &QAction::triggered, this,
            [=](){
        textEdit->setAlignment(Qt::AlignCenter);
    });
    connect(alignRAction, &QAction::triggered, this,
            [=](){
        textEdit->setAlignment(Qt::AlignRight);
    });
    connect(alignJAction, &QAction::triggered, this,
            [=](){ textEdit->setAlignment(Qt::AlignJustify); });
    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
}

void TextEditorDialog::loadTextDocument(const QString &document)
{
    textEdit->setHtml(document);
    setFormatTools();
}

QString TextEditorDialog::saveTextDocument()
{
    return textEdit->toHtml();
}

void TextEditorDialog::setFormatTools()
{
    blockSignals(true);

    fontComboBox->setCurrentFont(textEdit->currentFont());
    fontSizeComboBox->setCurrentText(QString::number(textEdit->currentFont().pointSize()));
    boldAction->setChecked(textEdit->fontWeight() == QFont::Bold);
    italicAction->setChecked(textEdit->fontItalic());
    underlineAction->setChecked(textEdit->fontUnderline());

    fontColor->setColorSlot(textEdit->textColor());
    backgroundColor->setColorSlot(textEdit->textBackgroundColor());

    alignLAction->setChecked(textEdit->alignment() == Qt::AlignLeft);
    alignCAction->setChecked(textEdit->alignment() == Qt::AlignCenter);
    alignRAction->setChecked(textEdit->alignment() == Qt::AlignRight);
    alignJAction->setChecked(textEdit->alignment() == Qt::AlignJustify);

    blockSignals(false);
}

void TextEditorDialog::blockSignals(bool status)
{
    fontComboBox->blockSignals(status);
    fontSizeComboBox->blockSignals(status);

    boldAction->blockSignals(status);
    italicAction->blockSignals(status);
    underlineAction->blockSignals(status);
}

void TextEditorDialog::slotCursorPositionChange()
{
    setFormatTools();
}

void TextEditorDialog::slotChangeFontColor(const QColor color)
{
    textEdit->setTextColor(color);
    fontColor->setColorSlot(color);
}

void TextEditorDialog::slotChangeBackgroundColor(const QColor color)
{
    textEdit->setTextBackgroundColor(color);
    backgroundColor->setColorSlot(color);
}

Thanks!

JonB · 15 Jan 2023, 19:15

@wazzdaman
Font families are listed in order or preference. The first one it can supply is used. Since you have Arial first in each case that will be used.

wazzdaman · J JonB 15 Jan 2023, 13:55

@JonB Thanks for the fast answer! The order of use is clear to me. My question is why is Arial never replaced after font change?

Soren Juul · 6 Feb 2024, 10:11

I have run into the same problem using Qt 5.15.2.
Setting fontFamily(name) on QTextEdit will not change the font name, but append it as a secondary name, causing QTextEdit to not show the correct font, since it uses the first font name.

This does not happen if QTextEdit is set with a plain text, but setHtml(ht) will cause the problem.
The following code example shows the problem without using UI.

      QTextEdit te;
      // Start by setting a text using Arial
      te.setFontFamily("Arial");
      te.setText("ABC");
      // The html output shows ... font-family:'Arial'
      QString html = te.toHtml();
      qDebug() << "html 1" << html;
      // Then select all text and change font to Calibri
      QTextCursor crs = te.textCursor();
      crs.movePosition(QTextCursor::Start);
      crs.movePosition(QTextCursor::End, QTextCursor::KeepAnchor);
      te.setTextCursor(crs);
      te.setFontFamily("Calibri");
      // The html output is still good with ... font-family:'Calibri'
      html = te.toHtml();
      qDebug() << "html 2" << html;
      // Change the font back to Arial
      te.setFontFamily("Arial");
      // The html output is still good with ... font-family:'Arial'
      html = te.toHtml();
      qDebug() << "html 3" << html;
      // Now set the text using the good html with Arial
      te.setHtml(html);
      // Again select all text and set the font to Calibri
      crs = te.textCursor();
      crs.movePosition(QTextCursor::Start);
      crs.movePosition(QTextCursor::End, QTextCursor::KeepAnchor);
      te.setTextCursor(crs);
      te.setFontFamily("Calibri");
      // Now the html output is bad with ... font-family:'Arial','Calibri'
      html = te.toHtml();
      qDebug() << "html 4" << html;

The output from above code:
html 1 "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">\n<html><head><meta name="qrichtext" content="1" /><style type="text/css">\np, li { white-space: pre-wrap; }\n</style></head><body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">\n<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'Arial';">ABC</span></p></body></html>"

html 2 "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">\n<html><head><meta name="qrichtext" content="1" /><style type="text/css">\np, li { white-space: pre-wrap; }\n</style></head><body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">\n<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'Calibri';">ABC</span></p></body></html>"

html 3 "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">\n<html><head><meta name="qrichtext" content="1" /><style type="text/css">\np, li { white-space: pre-wrap; }\n</style></head><body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">\n<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'Arial';">ABC</span></p></body></html>"

html 4 "<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">\n<html><head><meta name="qrichtext" content="1" /><style type="text/css">\np, li { white-space: pre-wrap; }\n</style></head><body style=" font-family:'MS Shell Dlg 2'; font-size:8.25pt; font-weight:400; font-style:normal;">\n<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'Arial','Calibri';">ABC</span></p></body></html>"

where the last line with font-family:'Arial','Calibri' is not as expected.
It should only say Calibri to work correctly.

Kind regards
Søren

lalula · wrote on 6 Feb 2024, 10:11

@Soren-Juul
I know this post is old, but ...

I had a similar problem changing the font on a QtextCursor in QTextEdit
I solved it by using setFontFamilies instead of setFontFamily

here a snip of my solution:

QTextCursor cursor = ui->textEdit->textCursor();
QTextCharFormat current = cursor.charFormat();
QStringList ffamily;
ffamily.append(font);
current.setFontFamilies(ffamily);
cursor.setCharFormat(current);