I have an escape sequences in a text, like
char const * text = "\e[1;33m" "some colored text" "\e[0m";
Which usually printed in terminal. But I want to forward this text in QTextEdit.
What is the simpliest way to make such text in QTextEdit colored? How to perform a filtering of escape sequences, i.e. how replace its with proper text formatting?
I think there is QSyntaxHighlighter-aided solution possible, but I don't know what to do with escape sequences itself and how to hide they from the output.
UPDATE: There is relevant code in qt-creator repo
Finally, I found the approach (it is understood, that QTextEdit::setReadOnly(true)):
// based on information: http://en.m.wikipedia.org/wiki/ANSI_escape_code http://misc.flogisoft.com/bash/tip_colors_and_formatting http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
void MainWindow::parseEscapeSequence(int attribute, QListIterator< QString > & i, QTextCharFormat & textCharFormat, QTextCharFormat const & defaultTextCharFormat)
{
switch (attribute) {
case 0 : { // Normal/Default (reset all attributes)
textCharFormat = defaultTextCharFormat;
break;
}
case 1 : { // Bold/Bright (bold or increased intensity)
textCharFormat.setFontWeight(QFont::Bold);
break;
}
case 2 : { // Dim/Faint (decreased intensity)
textCharFormat.setFontWeight(QFont::Light);
break;
}
case 3 : { // Italicized (italic on)
textCharFormat.setFontItalic(true);
break;
}
case 4 : { // Underscore (single underlined)
textCharFormat.setUnderlineStyle(QTextCharFormat::SingleUnderline);
textCharFormat.setFontUnderline(true);
break;
}
case 5 : { // Blink (slow, appears as Bold)
textCharFormat.setFontWeight(QFont::Bold);
break;
}
case 6 : { // Blink (rapid, appears as very Bold)
textCharFormat.setFontWeight(QFont::Black);
break;
}
case 7 : { // Reverse/Inverse (swap foreground and background)
QBrush foregroundBrush = textCharFormat.foreground();
textCharFormat.setForeground(textCharFormat.background());
textCharFormat.setBackground(foregroundBrush);
break;
}
case 8 : { // Concealed/Hidden/Invisible (usefull for passwords)
textCharFormat.setForeground(textCharFormat.background());
break;
}
case 9 : { // Crossed-out characters
textCharFormat.setFontStrikeOut(true);
break;
}
case 10 : { // Primary (default) font
textCharFormat.setFont(defaultTextCharFormat.font());
break;
}
case 11 ... 19 : {
QFontDatabase fontDatabase;
QString fontFamily = textCharFormat.fontFamily();
QStringList fontStyles = fontDatabase.styles(fontFamily);
int fontStyleIndex = attribute - 11;
if (fontStyleIndex < fontStyles.length()) {
textCharFormat.setFont(fontDatabase.font(fontFamily, fontStyles.at(fontStyleIndex), textCharFormat.font().pointSize()));
}
break;
}
case 20 : { // Fraktur (unsupported)
break;
}
case 21 : { // Set Bold off
textCharFormat.setFontWeight(QFont::Normal);
break;
}
case 22 : { // Set Dim off
textCharFormat.setFontWeight(QFont::Normal);
break;
}
case 23 : { // Unset italic and unset fraktur
textCharFormat.setFontItalic(false);
break;
}
case 24 : { // Unset underlining
textCharFormat.setUnderlineStyle(QTextCharFormat::NoUnderline);
textCharFormat.setFontUnderline(false);
break;
}
case 25 : { // Unset Blink/Bold
textCharFormat.setFontWeight(QFont::Normal);
break;
}
case 26 : { // Reserved
break;
}
case 27 : { // Positive (non-inverted)
QBrush backgroundBrush = textCharFormat.background();
textCharFormat.setBackground(textCharFormat.foreground());
textCharFormat.setForeground(backgroundBrush);
break;
}
case 28 : {
textCharFormat.setForeground(defaultTextCharFormat.foreground());
textCharFormat.setBackground(defaultTextCharFormat.background());
break;
}
case 29 : {
textCharFormat.setUnderlineStyle(QTextCharFormat::NoUnderline);
textCharFormat.setFontUnderline(false);
break;
}
case 30 ... 37 : {
int colorIndex = attribute - 30;
QColor color;
if (QFont::Normal < textCharFormat.fontWeight()) {
switch (colorIndex) {
case 0 : {
color = Qt::darkGray;
break;
}
case 1 : {
color = Qt::red;
break;
}
case 2 : {
color = Qt::green;
break;
}
case 3 : {
color = Qt::yellow;
break;
}
case 4 : {
color = Qt::blue;
break;
}
case 5 : {
color = Qt::magenta;
break;
}
case 6 : {
color = Qt::cyan;
break;
}
case 7 : {
color = Qt::white;
break;
}
default : {
Q_ASSERT(false);
}
}
} else {
switch (colorIndex) {
case 0 : {
color = Qt::black;
break;
}
case 1 : {
color = Qt::darkRed;
break;
}
case 2 : {
color = Qt::darkGreen;
break;
}
case 3 : {
color = Qt::darkYellow;
break;
}
case 4 : {
color = Qt::darkBlue;
break;
}
case 5 : {
color = Qt::darkMagenta;
break;
}
case 6 : {
color = Qt::darkCyan;
break;
}
case 7 : {
color = Qt::lightGray;
break;
}
default : {
Q_ASSERT(false);
}
}
}
textCharFormat.setForeground(color);
break;
}
case 38 : {
if (i.hasNext()) {
bool ok = false;
int selector = i.next().toInt(&ok);
Q_ASSERT(ok);
QColor color;
switch (selector) {
case 2 : {
if (!i.hasNext()) {
break;
}
int red = i.next().toInt(&ok);
Q_ASSERT(ok);
if (!i.hasNext()) {
break;
}
int green = i.next().toInt(&ok);
Q_ASSERT(ok);
if (!i.hasNext()) {
break;
}
int blue = i.next().toInt(&ok);
Q_ASSERT(ok);
color.setRgb(red, green, blue);
break;
}
case 5 : {
if (!i.hasNext()) {
break;
}
int index = i.next().toInt(&ok);
Q_ASSERT(ok);
switch (index) {
case 0x00 ... 0x07 : { // 0x00-0x07: standard colors (as in ESC [ 30..37 m)
return parseEscapeSequence(index - 0x00 + 30, i, textCharFormat, defaultTextCharFormat);
}
case 0x08 ... 0x0F : { // 0x08-0x0F: high intensity colors (as in ESC [ 90..97 m)
return parseEscapeSequence(index - 0x08 + 90, i, textCharFormat, defaultTextCharFormat);
}
case 0x10 ... 0xE7 : { // 0x10-0xE7: 6*6*6=216 colors: 16 + 36*r + 6*g + b (0≤r,g,b≤5)
index -= 0x10;
int red = index % 6;
index /= 6;
int green = index % 6;
index /= 6;
int blue = index % 6;
index /= 6;
Q_ASSERT(index == 0);
color.setRgb(red, green, blue);
break;
}
case 0xE8 ... 0xFF : { // 0xE8-0xFF: grayscale from black to white in 24 steps
qreal intensity = qreal(index - 0xE8) / (0xFF - 0xE8);
color.setRgbF(intensity, intensity, intensity);
break;
}
}
textCharFormat.setForeground(color);
break;
}
default : {
break;
}
}
}
break;
}
case 39 : {
textCharFormat.setForeground(defaultTextCharFormat.foreground());
break;
}
case 40 ... 47 : {
int colorIndex = attribute - 40;
QColor color;
switch (colorIndex) {
case 0 : {
color = Qt::darkGray;
break;
}
case 1 : {
color = Qt::red;
break;
}
case 2 : {
color = Qt::green;
break;
}
case 3 : {
color = Qt::yellow;
break;
}
case 4 : {
color = Qt::blue;
break;
}
case 5 : {
color = Qt::magenta;
break;
}
case 6 : {
color = Qt::cyan;
break;
}
case 7 : {
color = Qt::white;
break;
}
default : {
Q_ASSERT(false);
}
}
textCharFormat.setBackground(color);
break;
}
case 48 : {
if (i.hasNext()) {
bool ok = false;
int selector = i.next().toInt(&ok);
Q_ASSERT(ok);
QColor color;
switch (selector) {
case 2 : {
if (!i.hasNext()) {
break;
}
int red = i.next().toInt(&ok);
Q_ASSERT(ok);
if (!i.hasNext()) {
break;
}
int green = i.next().toInt(&ok);
Q_ASSERT(ok);
if (!i.hasNext()) {
break;
}
int blue = i.next().toInt(&ok);
Q_ASSERT(ok);
color.setRgb(red, green, blue);
break;
}
case 5 : {
if (!i.hasNext()) {
break;
}
int index = i.next().toInt(&ok);
Q_ASSERT(ok);
switch (index) {
case 0x00 ... 0x07 : { // 0x00-0x07: standard colors (as in ESC [ 40..47 m)
return parseEscapeSequence(index - 0x00 + 40, i, textCharFormat, defaultTextCharFormat);
}
case 0x08 ... 0x0F : { // 0x08-0x0F: high intensity colors (as in ESC [ 100..107 m)
return parseEscapeSequence(index - 0x08 + 100, i, textCharFormat, defaultTextCharFormat);
}
case 0x10 ... 0xE7 : { // 0x10-0xE7: 6*6*6=216 colors: 16 + 36*r + 6*g + b (0≤r,g,b≤5)
index -= 0x10;
int red = index % 6;
index /= 6;
int green = index % 6;
index /= 6;
int blue = index % 6;
index /= 6;
Q_ASSERT(index == 0);
color.setRgb(red, green, blue);
break;
}
case 0xE8 ... 0xFF : { // 0xE8-0xFF: grayscale from black to white in 24 steps
qreal intensity = qreal(index - 0xE8) / (0xFF - 0xE8);
color.setRgbF(intensity, intensity, intensity);
break;
}
}
textCharFormat.setBackground(color);
break;
}
default : {
break;
}
}
}
break;
}
case 49 : {
textCharFormat.setBackground(defaultTextCharFormat.background());
break;
}
case 90 ... 97 : {
int colorIndex = attribute - 90;
QColor color;
switch (colorIndex) {
case 0 : {
color = Qt::darkGray;
break;
}
case 1 : {
color = Qt::red;
break;
}
case 2 : {
color = Qt::green;
break;
}
case 3 : {
color = Qt::yellow;
break;
}
case 4 : {
color = Qt::blue;
break;
}
case 5 : {
color = Qt::magenta;
break;
}
case 6 : {
color = Qt::cyan;
break;
}
case 7 : {
color = Qt::white;
break;
}
default : {
Q_ASSERT(false);
}
}
color.setRedF(color.redF() * 0.8);
color.setGreenF(color.greenF() * 0.8);
color.setBlueF(color.blueF() * 0.8);
textCharFormat.setForeground(color);
break;
}
case 100 ... 107 : {
int colorIndex = attribute - 100;
QColor color;
switch (colorIndex) {
case 0 : {
color = Qt::darkGray;
break;
}
case 1 : {
color = Qt::red;
break;
}
case 2 : {
color = Qt::green;
break;
}
case 3 : {
color = Qt::yellow;
break;
}
case 4 : {
color = Qt::blue;
break;
}
case 5 : {
color = Qt::magenta;
break;
}
case 6 : {
color = Qt::cyan;
break;
}
case 7 : {
color = Qt::white;
break;
}
default : {
Q_ASSERT(false);
}
}
color.setRedF(color.redF() * 0.8);
color.setGreenF(color.greenF() * 0.8);
color.setBlueF(color.blueF() * 0.8);
textCharFormat.setBackground(color);
break;
}
default : {
break;
}
}
}
void MainWindow::setTextTermFormatting(QTextEdit * textEdit, QString const & text)
{
QTextDocument * document = textEdit->document();
QRegExp const escapeSequenceExpression(R"(\x1B\[([\d;]+)m)");
QTextCursor cursor(document);
QTextCharFormat const defaultTextCharFormat = cursor.charFormat();
cursor.beginEditBlock();
int offset = escapeSequenceExpression.indexIn(text);
cursor.insertText(text.mid(0, offset));
QTextCharFormat textCharFormat = defaultTextCharFormat;
while (!(offset < 0)) {
int previousOffset = offset + escapeSequenceExpression.matchedLength();
QStringList capturedTexts = escapeSequenceExpression.capturedTexts().back().split(';');
QListIterator< QString > i(capturedTexts);
while (i.hasNext()) {
bool ok = false;
int attribute = i.next().toInt(&ok);
Q_ASSERT(ok);
parseEscapeSequence(attribute, i, textCharFormat, defaultTextCharFormat);
}
offset = escapeSequenceExpression.indexIn(text, previousOffset);
if (offset < 0) {
cursor.insertText(text.mid(previousOffset), textCharFormat);
} else {
cursor.insertText(text.mid(previousOffset, offset - previousOffset), textCharFormat);
}
}
cursor.setCharFormat(defaultTextCharFormat);
cursor.endEditBlock();
//cursor.movePosition(QTextCursor::Start);
textEdit->setTextCursor(cursor);
}
It is not fully tested at the moment, but quite workable. It is exact what I wanted.