In QML (QtQuick 2.0), FontMetrics provides every info about a font's size except its cap height. I really need to find out the cap height of a font for a program (it even provides xHeight but not the cap height!!). Is there a mathematical relation between the x height and cap height? If not, is there any other way of finding the cap height of a font?
Please help! I actually tried searching for all possible solutions but couldn't find anything!
The QFontMetricsF has capHeight method.
https://doc.qt.io/qt-5/qfontmetricsf.html#capHeight
May be you can expose from C++ as said below. If that works, QFontMetricsF has much better interface which you can use.
The below code is hand written (syntax or compiler errors will be there). But gives you an idea.
//EXPOSE THE INFORMATION FROM C++
class fontDetails : public QObject
{
Q_OBJECT
Q_PROPERTY(qreal capHeight READ GetCapHeight CONSTANT)
public:
qreal GetCapHeight() const {
return QFontMetricsF(<<YOUR FONT>>).capHeight();
}
};
//SET THE CONTEXT
int main(int argc, char *argv[]) {
QGuiApplication app(argc, argv);
QQuickView view;
fontDetails fontdetails;
view.engine()->rootContext()->setContextProperty("fontdetails", &fontdetails);
view.setSource(QUrl::fromLocalFile("<<YOUR QML>>.qml"));
view.show();
return app.exec();
}
And then consume in QML
Label {
text: fontdetails.GetCapHeight()
}
Related
I was trying to understand if there is a way to build a particular customized QPushButton?
What I am trying to achieve is the following layout and appearance:
The button is shown below, notice the red line (which meas that the button is not clicked). I am not sure how to achieve the red line. I think it could be widget? or a QProgressbar, that when is clicked goes/loads up to green..I am not sure because I don't have enough experience and have been trying to build it. However this seems to be a bit tough:
And below how it should look like right after the click happened (note the green line):
Despite my efforts, I found some useful sources that I could use to get me started: for example this source was great to understand how to start. I studied the fact that in order to achieve that, the button need to be subclassed, and that is great because it lays some sort of route.
Below the code I used:
custombutton.h
#ifndef CUSTOMBUTTON_H
#define CUSTOMBUTTON_H
#include <QPushButton>
class CustomButton : public QPushButton
{
public:
CustomButton( const QString& text, QWidget* parent = 0 );
void writeText();
};
#endif // CUSTOMBUTTON_H
custombutton.cpp
#include "CustomButton.h"
#include "algorithm"
CustomButton::CustomButton( const QString& text, QWidget* parent )
: QPushButton( text, parent )
{
}
void CustomButton::writeText()
{
QString buttonText = text();
setText( buttonText );
}
main
#include <QApplication>
#include "CustomButton.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
CustomButton w( "MyButton" );
w.show();
w.writeText();
a.exec();
return 0;
}
Another useful source I found is this one which also was useful.
The official documentation points to use the styles, but I am trying not to do that because I would like to solve the problem understanding what is the potential of subclassing with Qt.
Unless going in the style direction is the only possible way to solve this problem?
I would like to thank anyone in advance for sharing or pointing to a potential solution on how to do that.
You can set your button as checkable and then set a different icon for the 2 states.
In your case you'd have to set the red icon for the Normal mode and the green one for the Selected mode
Here's an example:
https://www.dropbox.com/s/x40byuyu2ph8m1y/CheckableButton.zip?dl=0
Here someone asked the same thing:
https://forum.qt.io/topic/72363/change-icon-of-pushbutton
Here you can read abouth the modes:
https://doc.qt.io/qt-5/qicon.html#Mode-enum
PS: Of course overriding QAbstractButton::paintEvent(QPaintEvent *event) is a viable option too
I am struggling to get a QGraphicsTextItem to work as a user friendly object.
Since it is very hard to move while being editable, I start it as not editable, and make it editable on double-click. Then turn editing off on losing focus.
My problem is, the caret does not show up on first edit.
I have tried getting the position based on mouse position (as in this question that was trying to solve a different problem), or calling the QGraphicsTextItem::mouseDoubleClickEvent(event);
No matter what I try, the caret is invisible on first action - until I start typing (or if I focus out and back in) - even though it is at the correct location.
After typing, or unselecting and reselecting , the caret shows up in normal location every time.
I have tried to call the QTextCursor in the item constructor, setting its position at 0, made no difference.
What made a difference : one of the 2 situations (neither of which I can do though):
a) start item with Qt::TextEditorInteraction in constructor
b) start item with no moving/focus/selectable flags
I can't do either - because my default state of item must be movable, and that interferes with text editing (as explained at start).
I have tried to disable those flags during editing though... with no effect.
Here is a simple code to demonstrate the problem, I hope somebody can have an idea.
mytextitem.h
#ifndef TEXTITEM_H
#define TEXTITEM_H
#include <QGraphicsTextItem>
class MyTextItem : public QGraphicsTextItem
{
Q_OBJECT
public:
MyTextItem();
protected:
virtual void focusOutEvent (QFocusEvent * event);
virtual void mouseDoubleClickEvent(QGraphicsSceneMouseEvent * event);
};
#endif // TEXTITEM_H
mytextitem.cpp
#include "mytextitem.h"
#include <QTextCursor>
#include <QAbstractTextDocumentLayout>
#include <QGraphicsSceneMouseEvent>
#include <QFont>
MyTextItem::MyTextItem()
{
setHtml("ABCD");
setFont(QFont("Arial", 50));
setTextInteractionFlags(Qt::NoTextInteraction);
setFlags(QGraphicsItem::ItemIsSelectable | QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsFocusable);
}
void MyTextItem::focusOutEvent(QFocusEvent *event)
{
Q_UNUSED(event);
setTextInteractionFlags(Qt::NoTextInteraction);
QTextCursor _cursor = textCursor();
_cursor.clearSelection();
setTextCursor(_cursor);
}
void MyTextItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
setTextInteractionFlags(Qt::TextEditorInteraction);
QGraphicsTextItem::mouseDoubleClickEvent(event); // or the version in linked question
}
main.cpp
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QGraphicsScene s;
QGraphicsView view(&s);
s.setSceneRect(-20, -100, 800, 600);
view.show();
MyTextItem* t = new MyTextItem();
s.addItem(t);
return app.exec();
}
I have also considered editing text - not sure if that would work but I think it would affect the undo stack which I will have to deal with soon....
How can I get my caret to show up on first double-click action on the text item ?
(As a user, not seeing a caret would make me uncertain if I can type... even though it works... I would not have confidence in the object if I do not have feedback of my action. That's why I care about this problem.)
I can't explain it... after trying EVERYTHING to get the caret to show, the solution was so simple:
I had to change the order of flags being set, in constructor.
The QGraphicsTextItem flag must be set AFTER setting the QGraphicsItem flags.
setFlags(QGraphicsItem::ItemIsSelectable | QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsFocusable);
setTextInteractionFlags(Qt::NoTextInteraction);
Although Qt's docs indicate that these two functions are different (the first doesn't include the frame) no matter what widget I choose - including the main window of my application - someWidget->frameGeometry().height() always returns the same value as someWidget->geometry.height().
What am I missing here?
I think, you don't give enough time to widget to be painted. There is little example:
#include <QApplication>
#include <QMainWindow>
#include <QDebug>
class MainWindow : public QMainWindow
{
public:
MainWindow() {
startTimer(500);
}
void timerEvent(QTimerEvent *e) {
// Here values are different
qDebug() << geometry().height() << frameGeometry().height();
}
};
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MainWindow mainWin;
mainWin.show();
// Here values are equals
qDebug() << mainWin.geometry().height() << mainWin.frameGeometry().height();
return app.exec();
}
First debug output will produce the same values for geometry and frameGeometry, but the second (in timerEvent) will produce different.
The QWidget class cannot have a frame. For example, QWidget doesn't have a frame, but QFrame has a frame.
if QWidget is toplevel window then you can see borders and title bar around it. We call it frame or decoration frame and frameGeometry() returns exactly that: window size and position which includes OS decorations.On the other side geometry() returs QWidget inner rect which is available for other child controls or painting.See http://doc.qt.io/qt-4.8/application-windows.html#window-geometry for more details.Toplevel geometry() / frameGeometry() differs if our window is not frameless or fullscreen ... or we are talking about some frameless window manager under x11.
this is an old post, but that could help those searching for the same problem.
Just call
adjustSize();
before prompting for some geometry attributes
As user fasked notes, frameGeometry() may not include the frame margins early in the window creation lifecycle. I have found that the following code works in some situations where calling frameGeometry() does not.
QMargins frameMargins;
QWindow *window = widget->windowHandle();
if (window) {
window->create();
frameMargins = window->frameMargins();
}
QRect myFrameGeometry = widget->geometry().adjusted(
-frameMargins.left(), -frameMargins.top(),
frameMargins.right(), frameMargins.bottom());
I am creating A Sortable List in Qt. The Code works perfectly well for Downward Scroll but when i having some issues getting the draggable item after i scroll the list down. I have added some test case screenshot for better understanding
Well this is the test case code
#include <QtGui>
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QListWidget *listWidget = new QListWidget;
for(int i=0;i<100;++i){
listWidget->addItem("SongOne");
listWidget->addItem("SongTwo");
listWidget->addItem("SongThree");
listWidget->addItem("SongFour");
listWidget->addItem("SongFive");
}
listWidget->setDragDropMode(QAbstractItemView::InternalMove);
listWidget->setDragEnabled(true);
listWidget->setAcceptDrops(true);
listWidget->setDropIndicatorShown(true);
listWidget->viewport()->setAcceptDrops(true);
listWidget->setSelectionMode(QAbstractItemView::SingleSelection);
listWidget->show();
app.exec();
delete listWidget;
return 0;
}
Thankz for taking the time in reading my post. Do help me if you have any hint on what i am missing out.I think i am missing setting some property. In the main Program(not the test code), i tried rewriting the dragMoveEvent and few more method, but no use.
the problem here is not the drag and drop but the QRect that is created while doing Drag and Drop. In Figure Two the Qrect is Created but not in Figure Four
Try to remove the lines:
listWidget->setDragEnabled(true);
listWidget->setAcceptDrops(true);
listWidget->setDropIndicatorShown(true);
listWidget->viewport()->setAcceptDrops(true);
They may interfer with the "real" Drag'n'Drop system. Reordering is typically handled in an optimized way.
Another solution could be that you subclass QListWidget and get the element's index in the drag event and the other's element's index in the drop event. So you know what to reorder and where it should be placed (before or after the second element's index). The rest should be easy, just takeItem() and insertItem().
Hope I helped you with these two ways ;)
In win7, i was not able to reproduce the same behavior. It just works(even size hint is tweaked to meet your screen shot requirement. :) )
My test code was...
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QListWidget *listWidget = new QListWidget;
const char* titles[] = {
"SongOne%1",
"SongTwo%1",
"SongThree%1",
"SongFour%1",
"SongFive%1",
};
for(int i=0;i<100;++i){
QString title = QString(titles[i%5]).arg(i);
QListWidgetItem* item = new QListWidgetItem(title);
item->setData(Qt::SizeHintRole, QSize(50,100));
listWidget->addItem(item);
}
listWidget->setDragDropMode(QAbstractItemView::InternalMove);
listWidget->setDragEnabled(true);
listWidget->setAcceptDrops(true);
listWidget->setDropIndicatorShown(true);
listWidget->viewport()->setAcceptDrops(true);
listWidget->setSelectionMode(QAbstractItemView::SingleSelection);
listWidget->show();
app.exec();
delete listWidget;
return 0;
}
I would like to execute a QMenu object at the position of text cursor in a QPlainTextEdit. My problem is that QTextCursor is only define by its position in the Text (index of the character).
How can I find global position of the QTextCursor? Should I use an other object than QTextCursor in order to find the position of the text cursor where I want to open my QMenu?
Thank you by advance.
I've never tried myself, but doesn't QPlainTextEdit::cursorRect() work? It should give you position of the cursor in viewport coordinates. You can then get the viewport using viewport() and map the local position to global using viewport()->mapToGlobal().
I have found similar query to your in some online forum and here's someone suggested the output as
Note: Reference from http://www.unix.com/unix-linux-applications/81388-read-position-mouse-cursor.html, Author of below posting is daggilli, registered user of UNIX online forums. Credit of below posting in its complete form goes to daggilli.
This is the complete code for a Qt application I threw together in about ten minutes (called crosshair) which displays the current mouse coordinates in a window. You might be able to pull enough out of it to be useful. This is Qt 3.1, but Qt 4 is not a great deal different. You will need the Qt development libraries, not just the runtimes. The code comprises two files, crosshair.h and crosshair.cpp.
crosshair.h:
Code:
#ifndef CROSSHAIR_H
#define CROSSHAIR_H
#include <qwidget.h>
#include <qstring.h>
#include <qlabel.h>
#include <qevent.h>
class Crosshair : public QLabel
{
Q_OBJECT
public:
Crosshair(QWidget *parent=0);
protected:
void mousePressEvent(QMouseEvent *);
private:
QTimer *timer;
private slots:
void timerfire();
};
#endif
crosshair.cpp:
Code:
#include <qapplication.h>
#include <qpushbutton.h>
#include <qtimer.h>
#include <qcursor.h>
#include <iostream>
#include "crosshair.h"
using namespace std;
int main(int argc,char **argv)
{
QApplication a(argc,argv);
Crosshair mousepos;
a.setMainWidget(&mousepos);
mousepos.show();
return a.exec();
}
Crosshair::Crosshair(QWidget *parent) : QLabel(parent)
{
setIndent(20);
resize(100,30);
move(1200,200);
setText("0,0");
timer=new QTimer(this);
connect(timer,SIGNAL(timeout()),this,SLOT(timerfire()));
timer->start(50,false);
}
void Crosshair::mousePressEvent(QMouseEvent *)
{
qApp->quit();
}
void Crosshair::timerfire()
{
QPoint p=QCursor::pos();
this->setText(QString().sprintf("%d,%d",p.x(),p.y()));
}
To build this, put both files in a directory called crosshair. cd to that directory and type
Code:
qmake -project
qmake
make
This does nothing more complex than inherit from a QLabel, set a timer to run 20x a second, grab the current cursor coordinates and write them into the label's text. Clicking in the window closes it. I use it for fixing up alignment bugs in JavaScript when I'm laying out objects.
You could open a file in the Crosshair class's constructor to store your data, and use gettimeofday(2) to get a timestamp. Nothing says Qt has to run in GUI mode (you can tell it explicitly not to in the QApplication constructor).
Qt from Trolltech: http://doc.trolltech.com