How to change font weight at various locations within a QTextEdit

mulfycrowh

Hi,

Everything is in the title.
I have a text in a QTextEdit.
I would like, for example, to highlight titles with a bigger font.
Many thanks.

mrjj

Hi
The text is blocks/paragraphs and you use
QTextCursor and QTextBlockFormat to format it.

http://stackoverflow.com/questions/27716625/qtextedit-change-font-of-individual-paragraph-block

mulfycrowh

Thank you I'll take a look

mulfycrowh

Is it the only way ? I find it a little bit tricky, just to write a line (title) with a bigger font weight ...

mrjj

@mulfycrowh
well for a title you can also insert HTML
http://doc.qt.io/qt-5/qtextedit.html#html-prop

To "cheat" u can use the html editor ( right click the textedit in Designer)
and get the complete syntax and simply do some +text+ operation to set your title.

mulfycrowh

What do you think about the following thread :

http://www.qtcentre.org/threads/24331-How-to-set-text-and-font-in-qTextEdit

mrjj

well it shows a slightly smarter way to use html and
a cursor. so yes could also be used even u are then very close to the normal textformat way.

mulfycrowh

Here is what I wrote:

// convert a number into a QString made of 2 characters
QString Tools::toHexString(int value)
{
	QString sHex = QString::number(value, 16).toUpper();
	if (sHex.length() == 1)
		sHex.prepend('0');
	return sHex;
}


// highlight the text in QTextEdit edit at location for charcount characters
// (red, green, blue) is the color
// fontsize is the size of the font
// string may be highlighted with bold and underlined styles
void Tools::toHtml(QTextEdit* edit, int location, int charcount, int red, int green, int blue, int fontsize, bool bold, bool underlined)
{
	QTextCursor cursor(edit->document());
	QString highlight;
	QString sfont_beg = "<FONT ";
	QString sfont_end = "</FONT>";
	QString scolor = "color=#" + toHexString(red) + toHexString(green) + toHexString(blue) + " ";
	QString sbold = "span style=font-weight:bold ";
	QString sunderlined = "span style=text-decoration:underline ";
	QString ssize = "size=" + QString::number(fontsize) + ">";
	QString sHtml;

	cursor.setPosition(location, QTextCursor::MoveAnchor);
	cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, charcount);
	highlight = cursor.selectedText();
	sHtml = sfont_beg + scolor.toUpper();
	if (bold)
		sHtml = sHtml.append(sbold);
	if (underlined)
		sHtml = sHtml.append(sunderlined);
	sHtml = sHtml + ssize + highlight + sfont_end;
	cursor.insertHtml(sHtml);

}

It runs pretty well.
The trouble comes when I add several times (title + text) to the QTextEdit.
Each title has a length of 26 characters.
The length of each text is different.
I computed the location for each title as follows:

0 for the first one
26 + text0.length()
26 + text0.length() + 26 + text1.length()
...

If I apply this algorithm when I have appended all the texts to the QTextEdit, the fist title is well highlighted but there is a shift for the following ones.
I don't understand why.

mrjj

hi
nothing pop out in the code but i wonder if all (test) Titles are same color.
as you say
if (sHex.length() == 1)
sHex.prepend('0');

so maybe other color can alter the 26 offset ?

mulfycrowh

Yep. All titles are the same color.
Here is the code to highlight the titles:

	for (int Index = 0; Index < m_process.size(); ++Index)
		m_tools->toHtml(ui.Command_Edit, referenceLocation[Index], 17 + msg_description.length(), 0, 133, 255, 25, false, false);

But the trouble is that I encounter a shift about the highlighting. The first title is OK (obviously because 0), the following highlightings are false, I mean the location.
I don't see any problem.

mulfycrowh

I think I found the trouble : we have to substract the count of CR (or LF).
But I have to add 2, I don't understand why. It would mean that there are 2 extra characters that are not text.
So, for the algorithm of computing the location (vector referenceLocation - first element equals to 0), if I write:

			if (Index != 0) {
				referenceLocation.append(referenceLocation[Index - 1]);
				referenceLocation[Index] += m_command->getCommandFileContent(UNCOMPRESSED, UNCODED).size();
				referenceLocation[Index] += 17 + msg_description.length();
				referenceLocation[Index] -= m_command->getCommandFileContent(UNCOMPRESSED, UNCODED).count('\n');
				referenceLocation[Index] += 2;

information : title is made of 17 characters and description,

it runs perfectly !

mrjj

good found.
well a newline is \n\r on windows.
so maybe thats why with 2.

mulfycrowh

Hi folks !

I open this topic again because I get a weird thing.
Here is what I wrote:

void Tools::toHtml(QPlainTextEdit* edit, int location, int charcount, int red, int green, int blue, int fontsize, bool bold, bool underlined)
{
	QTextCursor cursor(edit->document());
	QString highlight;
	QString sfont_beg = "<FONT ";
	QString sfont_end = "</FONT>";
	QString scolor = "color=#" + toHexString(red) + toHexString(green) + toHexString(blue) + " ";
	QString sbold = "span style=font-weight:bold ";
	QString sunderlined = "span style=text-decoration:underline ";
	QString ssize = "size=" + QString::number(fontsize) + ">";
	QString sHtml;

	cursor.setPosition(location, QTextCursor::MoveAnchor);
	cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, charcount);
	highlight = cursor.selectedText();
	sHtml = sfont_beg + scolor.toUpper();
	if (bold)
		sHtml = sHtml.append(sbold);
	if (underlined)
		sHtml = sHtml.append(sunderlined);
	sHtml = sHtml + ssize + highlight + sfont_end;
	cursor.insertHtml(sHtml);

}

I call the function here:

m_tools->toHtml(m_descriptionPlainTextEdit, 0, 17 + msg_description.length(), 0, 133, 255, 25, false, false);

The title that has to be highlighted in blue has a length equal to 17 + msg_description.length().
Everything perfectly runs the first time, not the following ones : all the text in the text edit is highlighted in blue.
I don't see any trouble.

PS: the text edit is cleared each time.

Many thanks for help !

mrjj

Hi
ïf you put edit->clear();
in top, it really should do the same each time.

mulfycrowh

@mrjj Hi ! What do you mean in top ? In toHtml ? It would delete all the content.

mrjj

@mulfycrowh
Well you said
"PS: the text edit is cleared each time."
So I assumed you meant pr call to the function.

If all becomes blue it sounds like all is one paragraph.

You might need to use <p > </p> if the end result is something like

mulfycrowh

@mrjj The idea sounds interesting. I'll test it.
But why everything OK the first time and all the text blue with big size font the other ones ?
It acts as the QTextEdit keeps backup of something.
Thanks again !

mrjj

@mulfycrowh

But why everything OK the first time and all the text blue with big size font the other ones ?

I have not check output of the code but I assume it becomes
one big paragraph and therefore it is all blue.

But only way to tell is to see the generated HTML. step by step.

mulfycrowh

I added the following lines to toHtml ant it runs !

cursor.setPosition(charcount, QTextCursor::MoveAnchor);
cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, edit->document()->characterCount());
highlight = cursor.selectedText();
sHtml = "<FONT face=\"Arial\" font-weight=\"normal\" COLOR=#000000 size=\"3\">" + highlight + "</FONT>";
cursor.insertHtml(sHtml);

mulfycrowh

Nevertheless, I do not understand size=3 because, in the constructor I wrote:

	font.setPointSize(10);

Why 3 instead 10 ?

3 gives the same size.