How shall I get a QTreeWidgetItem LeftTop position (in pixel) after I get this item with the itemAt?
Is there a simple way?
If you have a QTreeWidgetItem * pitem you can use QTreeWidget::visualitemRect...
QRect viewport_relative_rect = pitem->treeWidget()->visualItemRect(pitem);
Related
I would like to "activate" the scrollbar when the lineedit text is too long to display on the window. I have already done it.
I want to move the cursor with the scrollbar. I also want to modify the scroll bar slider length with the increment/decrement of the text length.
.h
private:
Ui::MainWindow *ui;
QLineEdit* LineEdit;
QScrollBar* hScrollBar;
void HDScrollBar();
constructor:
resize(400,100);
LineEdit = new QLineEdit(this);
LineEdit->resize(400,100);
LineEdit->setFont(QFont("Times",20));
hScrollBar = new QScrollBar(Qt::Horizontal, LineEdit);
hScrollBar->resize(400,20);
hScrollBar->move(0,80);
hScrollBar->hide();
connect(LineEdit, &QLineEdit::textChanged, this, &MainWindow::HDScrollBar);
hide/display scrollbar
void MainWindow::HDScrollBar() {
QFont myFont(QFont("Times",20));;
QString str = LineEdit->text();
QFontMetrics fm(myFont);
int width = fm.horizontalAdvance(str);
(width >= 400) ? hScrollBar->show() : hScrollBar->hide();
}
As for the first part, you use can scrollbar's valueChanged signal, e.g. this way:
connect(ui->horizontalScrollBar, &QScrollBar::valueChanged, ui->lineEdit, [&](int v) {
auto scrollbarAt = static_cast<double>(v) / ui->horizontalScrollBar->maximum();
auto cursorTo = std::round(ui->lineEdit->text().length() * scrollbarAt);
ui->lineEdit->setCursorPosition(cursorTo);
});
EDIT:
as for the latter part:
you can either alter the PageStep of the scrollbar, or you can set it to 1 and alter its maximum value, then also the first part should simplify:
ui->horizontalScrollBar->setPageStep(1);
ui->horizontalScrollBar->setMaximum(ui->lineEdit.text().length());
connect(ui->horizontalScrollBar, &QScrollBar::valueChanged,
ui->lineEdit, &QLineEdit::setCursorPosition);
//this can also ben done on textChanged, however for the price
//of more frequent execution...
connect(ui->lineEdit, &QLineEdit::cursorPositionChanged,
ui->horizontalScrollBar, [&](int, int n) {
ui->horizontalScrollBar->setMaximum(ui->lineEdit->text().length());
//...one gets the easy way to track the cursor
//with the slider
ui->horizontalScrollBar->setValue(n);
});
my qgraphicsscene is having qgraphicswidget which constantly adding qgraphicsLayoutItem. in graphicsView i need to get the qgraphicswidget geometry in scene coordinated.
i tried
QList items = scene()->items();
and check its with type
foreach (QGraphicsItem *item, items) {
if(item->type() == ItemType)
{
}
but how to convert item to qgraphicswidget and change its gemoetry to scene coordinates.
normal item.boundingRect returns constantly 0,0, 10x10
The bounding rect of the item is in item coordinates. To map it to scene coordinates, use QGraphicsItem::mapToScene():
const QRectF mapped = item->mapToScene(item->boundingRect());
To cast a QGraphicsItem, you can simply use dynamic_cast or static_cast, or the special qgraphicsitem_cast:
auto widget = qgraphicsitem_cast<QGraphicsWidget*>(item);
To map the coordinates, casting shouldn’t be necessary though.
I am using QGraphicsTextItem to paint the text on the scene. Text is painted along the path (QGraphicsPathItem), wich is parent of my QGraphicsTextItem - so the text rotation is changed to be along the path element and is sticked to it while zooming the view. But the font size of QGraphicsTextItem is also changing while zooming the view - this is what I am trying to avoid. Of I set QGraphicsItem::ItemIgnoresTransformations flag to the QGraphicsTextItem it stops rotating while it's parent (QGraphicsPathItem) does.
I do understand that I have to re-implement QGraphicsTextItem::paint function, but I am stuck with the coordination system. Here is the code (Label class inherits public QGraphicsTextItem):
void Label::paint( QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget )
{
// Store current position and rotation
QPointF position = pos();
qreal angle = rotation();
// Store current transformation matrix
QTransform transform = painter->worldTransform();
// Reset painter transformation
painter->setTransform( QTransform() );
// Rotate painter to the stored angle
painter->rotate( angle );
// Draw the text
painter->drawText( mapToScene( position ), toPlainText() );
// Restore transformation matrix
painter->setTransform( transform );
}
The position (and rotation) of my text on the screen is unpredictable :(
What am I doing wrong? Thank you very much in advance.
I solved a problem this way - for drawing a line/circle/rectangle/path, which I want to be transformed, I use an appropriate QGraphicsLine/Ellipse/Rect/PathItem. For drawing the text (which I do NOT want to be transformed) I use QGraphicsSimpleTextItem. I set text's flag to ignore transormations and set it's parent to Line/Ellipse/Rect/Path item. The Line/Ellipse/Rect/Path item transforms, but text does not - this is what I wanted. I can also rotate text and set it's position.
Thank you very much for answers.
The following solution worked perfectly for me:
void MyDerivedQGraphicsItem::paint(QPainter *painter, const StyleOptionGraphicsItem *option, QWidget *widget)
{
double scaleValue = scale()/painter->transform().m11();
painter->save();
painter->scale(scaleValue, scaleValue);
painter->drawText(...);
painter->restore();
...
}
We can also multiply the scaleValue by other mesures we want to keep its size constant outside the save/restore environment.
QPointF ref(500, 500);
QPointF vector = scaleValue * QPointF(100, 100);
painter->drawLine(ref+vector, ref-vector);
I had this issue once. Instead of ignoring transformations, you need to scale down the items you don't want to be zoomed in in your zoom-in function.
When you zoom in, if you change the scale by ds for example, scale the items by 1.0 / ds
You might need to change their positions though.
I hope this helps.
Edit: I hope I understood the question right.
This is related to Qt: QListWidget separator line between items?
But this above answer adds separator line after each items, I would like to know a way to add the separator line after particular items.
Create a QListWidgetItem representing the separator. Such item would need to have defined the setSizeHint(), so its height is small, and also the setFlags() should define Qt::NoItemFlags, so the item is not selectable, etc. Then, after adding the item to the QListWidget, place a QFrame, with its shape set to QFrame::HLine, as the item's widget (using QListWidget::setItemWidget()).
As for your additional question from the comment, which is:
I want to add some gap on each sides of this separator line/frame. How can I achieve this?
The only solution that comes to my mind right now is to embed the QFrame inside of another QWidget and put the QWidget as item's widget (remember that you need to add a layout manager to the QWidget in order to embed anything in it). Then set proper margins on the widget: QWidget::setContentsMargins(int left, int top, int right, int bottom)
I found another possibility and tested it this time :p
You could create a new class inheriting QStyledItemDelegate that look like this :
void MyStyledItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QStyledItemDelegate::paint(painter, option, index);
// I have decided to use Qt::UserRole + 1 to store my boolean
// but it could be any other role while it's value is bigger than Qt::UserRole
QVariant isSeparator = index.data(Qt::UserRole + 1);
if (isSeparator.isValid() && isSeparator.toBool())
{
QRect rct = option.rect;
rct.setY(rct.bottom() - 1);
painter->fillRect(rct, QColor::fromRgb(qRgb(0, 0, 0)));
}
}
And the for each QListWidgetItem you can do the following :
// Qt::UserRole + 1 => Must match the role set in the delegate
item->setData(Qt::UserRole + 1, true);
Install the custom in your QListWidget like this
listWidget->setItemDelegate(new MyStyledItemDelegate());
It will draw a black line under the text of the item if the Qt::UserRole + 1 is set to true.
You can try using the same trick with dynamic properties.
myListWidget->setStyleSheet( "QListWidget::item[separator="true"] { border-bottom: 1px solid black; }" );
And on the widget you want the line to be drawn :
myWidget->setProperty("separator", true);
However be carefull the documentation says :
Warning: If the value of the Qt property changes after the style sheet has been set, it might be necessary to force a style sheet recomputation. One way to achieve this is to unset the style sheet and set it again.
I have a QGraphicsScene and a QGraphicsView that displays it. I need to add a QGraphicsItem to the scene and keep it at the same position even when I scroll the view. I tried overriding view's scrollContentsBy() method as follows but it didn't do the trick.
void FETimelineView::scrollContentsBy( int dx, int dy )
{
QGraphicsView::scrollContentsBy(dx, dy);
QRectF oRect = p_CatBar->rect();
p_CatBar->setPos( oRect.x() + dx, oRect.y() + dy );
}
Btw, FETimelineView is my QGraphicsView and p_CatBar is of type QGraphicsItem. Please help, thanks in advance.
Rather than moving it by the scrolled amount, You can get the position that you want it to be relative to the view and then set it directly according to that. So it would be something like this: -
// Assuming that the Graphics Item top left needs to be at 50,50
// and has a width and height of 30,20
void FETimelineView::scrollContentsBy( int dx, int dy )
{
QGraphicsView::scrollContentsBy(dx, dy);
// get the item's view position in scene coordinates
QRect scenePos = mapToScene(QRect(50, 50, 30, 20));
p_CatBar->setPos(scenePos);
}
I think the easier way it's actually the inverse of what you ask: try setting the flag ItemIgnoresTransformations in QGraphicsItem::GraphicsItemFlags.
There are other flags that could help you, see the docs.