QTextEdit with different text colors (Qt / C++)

Question

I have a QTextEdit box that displays text, and I'd like to be able to set the text color for different lines of text in the same QTextEdit box. (i.e. line 1 might be red, line 2 might be black, etc.)

Is this possible in a QTextEdit box? If not, what's the easiest way to get this behavior?

Thanks.

Solution 1

Use text formated as HTML, for example:

textEdit->setHtml(text);

where text, is a HTML formated text, contains with colored lines and etc.

Solution 2

Just a quick addition: an alternative to generating the html yourself, if you're populating the text box programatically, is to use textEdit->setTextColor(QColor&). You can create the QColor object yourself, or use one of the predefined colours in the Qt namespace (Qt::black, Qt::red, etc). It will apply the specified colour to any text you add, until it is called again with a different one.

Solution 3

The ONLY thing that worked for me was html.

Code snippet follows.

QString line = "contains some text from somewhere ..."
    :
    :
QTextCursor cursor = ui->messages->textCursor();
QString alertHtml = "<font color=\"DeepPink\">";
QString notifyHtml = "<font color=\"Lime\">";
QString infoHtml = "<font color=\"Aqua\">";
QString endHtml = "</font><br>";

switch(level)
{
    case msg_alert: line = alertHtml % line; break;
    case msg_notify: line = notifyHtml % line; break;
    case msg_info: line = infoHtml % line; break;
    default: line = infoHtml % line; break;
}

line = line % endHtml;
ui->messages->insertHtml(line);
cursor.movePosition(QTextCursor::End);
ui->messages->setTextCursor(cursor);

Solution 4

Link to doc

A few quotes:

QTextEdit is an advanced WYSIWYG viewer/editor supporting rich text formatting using HTML-style tags. It is optimized to handle large documents and to respond quickly to user input.

.

The text edit can load both plain text and HTML files (a subset of HTML 3.2 and 4).

.

QTextEdit can display a large HTML subset, including tables and images.

This means mostly deprecated tags and as such does not include any current CSS, so I turned to this:

// save    
int fw = ui->textEdit->fontWeight();
QColor tc = ui->textEdit->textColor();
// append
ui->textEdit->setFontWeight( QFont::DemiBold );
ui->textEdit->setTextColor( QColor( "red" ) );
ui->textEdit->append( entry );
// restore
ui->textEdit->setFontWeight( fw );
ui->textEdit->setTextColor( tc );

Solution 5

Extending on https://stackoverflow.com/a/13287446/1619432:

QTextEdit::append() inserts a new paragraph with the previously set FontWeight / TextColor. insertHTML() or InsertPlainText() to avoid inserting a new paragraph (e.g. to achieve different formats in a single line) do not respect the font/color settings.

Instead use QTextCursor:

...
// textEdit->moveCursor( QTextCursor::End );
QTextCursor cursor( textEdit->textCursor() );

QTextCharFormat format;
format.setFontWeight( QFont::DemiBold );
format.setForeground( QBrush( QColor( "black" ) ) );
cursor.setCharFormat( format );

cursor.insertText( "Hello world!" );
...

View more solutions

Comments

[SirDarius]

This is by far the simplest solution to do so. Works like a charm for example for logging, where each line is colored according to the message's severity.

[Master Yoda]

but this only colors all the text present , i want to color each color with a diff color , can u please help me with that ?

[Master Yoda]

this answer taught me new things

[earth]

This wound up working for me. One line is one color, and the next line is a different color. In this example, after "Hello World", you would put lines format.setForeground( QBrush( QColor( "white" ) ) ); and cursor.setCharFormat( format ); and cursor.insertText( "This line is white" );.

[e-holder]

If you are using a 'textEdit' object, it will color the text of each 'append' call with a different color.

[Ternvein]

The problem is that original text colour is theme-dependent and may be anything, not only black.

[Owl]

No. This isn't necessary.