line spaceing in QTextDocument

[tuli]

Following my previous post, i`d need custom line spacing in a QTextDocument.

No proper solution was found here:
http://www.qtcentre.org/threads/19297-QTextDocument-line-spacing

But after the post, an addition was supposedly made to Qt in 4.8.0:
https://bugreports.qt-project.org/browse/QTBUG-14470


Status: Closed Closed
Priority: P2: Important P2: Important
Resolution: Done
Affects Version/s: 4.7.0
Fix Version/s: 4.8.0

However, the thread fails to mention what exactly was added/changed, and i am unable to find anything in Qt 4.8.1. :/

I figured i am supposed to layout every single paragraph in the document by subclassing this:
http://doc.qt.nokia.com/4.7-snapshot/qabstracttextdocumentlayout.html

but i still wouldnt know how to change the line space...


Funny, Qt offers so much awesomeness, and then it`s these little things that you are left spending time on...:eek:

[Lykurg]

Hi,

you can iterate through the blocks of QTextDocument and set the line spacing with QTextBlock::blockFormat() + QTextBlockFormat::setLineHeight().

[tuli]

thanks!

It wont work though...
I decided to go bruteforce onthis:



testform::testform(QWidget *parent, Qt::WFlags flags)
: QMainWindow(parent, flags)
{
ui.setupUi(this);


ui.textEdit->setText("asdfasdfasdf\r\nbbbbbbbbbbbbbbbbbbbb\r\ncccccccccc ccccccc\r\nddddddddddddddddddf");

for(int i=0; i<ui.textEdit->document()->blockCount(); i++)
{
ui.textEdit->document()->findBlockByNumber(i).blockFormat().setLineHeight(1 2, QTextBlockFormat::LineDistanceHeight);
}
}

But it doesnt work. :(

[Lykurg]

Of course it does not work. You have to set the modified format back to the document! blockFormat() simply returns a copy of the format, no pointer nor reference!
QTextEdit te;
te.setText("asdfasdfasdf\nbbbbbbbbbbbbbbbbbbbb\ncccccccccccccc ccc\nddddddddddddddddddf");
QTextCursor c(te.document());
c.movePosition(QTextCursor::Start);
do {
QTextBlockFormat f = c.blockFormat();
f.setLineHeight(12, QTextBlockFormat::LineDistanceHeight);
c.setBlockFormat(f);
} while (c.movePosition(QTextCursor::NextBlock));
te.show();

[tuli]

ouch...yeah, that was it. That makes a great second post, doesnt it...:(

So now i have this code to render a document to the screen:


painter->translate(x, y);
document()->setTextWidth(w);
document()->setDefaultFont(painter->font());


QTextCursor c(document());
c.movePosition(QTextCursor::Start);
do {
QTextBlockFormat f = c.blockFormat();
f.setLineHeight(h, QTextBlockFormat::LineDistanceHeight);
c.setBlockFormat(f);
} while (c.movePosition(QTextCursor::NextBlock));


document()->drawContents(painter, QRect(0,0,w,h));

This works perfectly for single-line strings, but not when strings with linebreaks in it have been assigned:


document().setPlainText("aaaaa\nbbbbbbb\ncccccc");

any idea?:)

[Lykurg]

any idea?:)Yes. The second parameter of drawContents clips the painting. So you have to alter "h" when you have more lines than one or just leave it empty.

[tuli]

h provide sufficient space, and


document()->drawContents(painter);

provides same result... :/

[Lykurg]

Then please make a minimal compile able example which illustrate your problem.