QTextEdit and color emulation of bash output
I have escape sequences in text like
char const * text = "\e[1;33m" "some colored text" "\e[0m";
Usually printed in the terminal. But I want to forward this text to QTextEdit .
What's the simplest way to make text like this in QTextEdit colored? How to filter escape sequences, i.e. How do I replace it with correct text formatting?
I think a QSyntaxHighlighter solution is possible , but I don't know what to do with the escape sequences themselves and how to hide them from output.
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2 answers
Finally I found an approach (understandably 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 it is quite functional. This is what I wanted.
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These are ANSI cancellation codes . They are very easy to parse, especially if you only have a small, fixed subset that you manage. There are probably libraries out there that can also help you parse escape codes, and if you see the need to support more codes than just colors then it might make sense to try to find them, but if you just want simple color codes and have full source control lines and then writing yours is probably faster.
So what you need to do is parse those escape codes from strings and replace them with Qt rich textual markup , which is a subset of HTML markup.
Another approach could be the opposite: save your strings with HTML (or some other) markup, and then convert them to ANSI codes for colored console output. With luck, you may even find a library that can convert HTML to text using ANSI escape codes.
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