[SOLVED] How to change the background color of selected text in QGraphicsTextItem?

Sam

Hi conny,
One solution can be to override the mousePressEvent() and mouseReleaseEvent() of yourGraphicsTextItem, then create a QRect from the event->pos() and fill the rectangle with the color.

Note: This is just an idea not yet tested!!!!
Regards
Soumitra

Wilk

Hello
Did you try "QGraphicsTextItem::setTextInteractionFlags":http://qt-project.org/doc/qt-4.8/qgraphicstextitem.html#setTextInteractionFlags with "Qt::TextSelectableByMouse":http://qt-project.org/doc/qt-4.8/qt.html#TextInteractionFlag-enum as an argument?
Or did I misunderstand what do you want?

Sam

Hi Wilk,

The attached image specifies his requirement.

[quote author="conny" date="1335769034"]Sure, I've uploaded an image here: "Image":http://twitpic.com/9fisl6/full

In words: I want to change the highlight/selection color that a word get marked with if I select it for copy&paste. Well, I think the image makes it clearer :)
[/quote]

conny

Hi Wilk,

I've set those flags and the text is selectable. Only the selection color is always blue and I need to change that color.

[quote author="Wilk" date="1336346790"]Hello
Did you try "QGraphicsTextItem::setTextInteractionFlags":http://qt-project.org/doc/qt-4.8/qgraphicstextitem.html#setTextInteractionFlags with "Qt::TextSelectableByMouse":http://qt-project.org/doc/qt-4.8/qt.html#TextInteractionFlag-enum as an argument?
Or did I misunderstand what do you want?[/quote]

conny

Hi Soumitra,

that might be an option and I'll try it. However I fear that painting that rectangle myself will interfere with the painting of the original text selection.

[quote author="Soumitra" date="1336294039"]Hi conny,
One solution can be to override the mousePressEvent() and mouseReleaseEvent() of yourGraphicsTextItem, then create a QRect from the event->pos() and fill the rectangle with the color.

Note: This is just an idea not yet tested!!!!
Regards
Soumitra[/quote]

Wilk

Hello again.
If you don't like blue background color, then look into Qt sources.
You will find out, that background color is selected automaticaly at qt_graphicsItem_highlightSelected method of QGraphicsItem, which is called from paint method of QGraphicsTextItem.
So one of the possible solutions is:

Create class, derived from QGraphicsTextItem.

Override paint method with something like @

class YourTextItem : public QGraphicsTextItem {
//...
QColor bgcolor;
//...
}

void YourTextItem::paint(QPainter *painter,
const QStyleOptionGraphicsItem *option,
QWidget *widget) {
Q_UNUSED(widget);
bool is_selected = option->state & (QStyle::State_Selected | QStyle::State_HasFocus);

if (is_selected) {
option->state &= ~QStyle::State_Selected;
}
QGraphicsTextItem::paint(painter,
option,
widget);
highlight (painter,
is_selected);
}

void YourTextItem::highlight (QPainter *painter,
bool is_selected) {
if (is_selected) {
const qreal itemPenWidth = 1.0;
const qreal pad = itemPenWidth / 2;

const qreal penWidth = 0; // cosmetic pen

const QColor fgcolor = option->palette.windowText().color();

painter->setPen(QPen(bgcolor, penWidth, Qt::SolidLine));
painter->setBrush(Qt::NoBrush);
painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));

painter->setPen(QPen(option->palette.windowText(), 0, Qt::DashLine));
painter->setBrush(Qt::NoBrush);
painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));

}
}
@
Try this out, but I didn't test it.

conny

Thank you very much for that code. I'll try it and report back here.

conny

Hi Wilk,

I found time to look at your code now. Sorry for the delay. Unfortunately all it does is changing the style of the text item itself. It does not change the text selection inside the text item.

However, I've followed your advice and read the Qt code until I found out where the styling actually happens. If anyone is interested have a look at:

QTextDocumentLayout::draw() and
QTextControl::getPaintContext()

To make a long story short, I finally found a way that works. The solution is way easier than I thought and you don't even have to override anything. Here is the code:

@
QPalette p;
p.setBrush(QPalette::Active, QPalette::Highlight, QBrush(QColor("pink")));
p.setBrush(QPalette::Inactive, QPalette::Highlight, QBrush(QColor("pink")));
p.setBrush(QPalette::Active, QPalette::HighlightedText, QBrush(QColor("green")));
p.setBrush(QPalette::Inactive, QPalette::HighlightedText, QBrush(QColor("green")));
QApplication::setPalette(p, "QTextControl");
@

Thanks everyone for the help :)

Sam

Hi Conny,
Good that you got the solution, and thanks for sharing the code so that we can also use the same. You can edit your first post and add [SOLVED] to the title.

Happy Coding :)

conny

Already done. Thanks!

Wilk

Hello
Thanks for a proper solution.

conny

The only disadvantage of this solution is, that it does not really work during runtime. Setting the value during application start-up works, but changing it later has no effect.

For me this is currently not a problem, but I thought I should still mention it.