I would like to lock my app developed with Qt to landscape orientation, even if the screen display is portrait. I have tried adding to my code the resizeEvent method found here: http://qt-project.org/doc/qt-4.8/widgets-orientation.html, but my app still does not display correctly. Here is my code for resizeEvent:
void MainWindow::resizeEvent(QResizeEvent *event)
{
QSize size = event->size();
qDebug() << size;
bool isLandscape = size.width() > size.height();
if (isLandscape == false){
size.transpose();
}
this->setFixedSize(size);
}
Does anyone know how to do this in Qt 4.8.5? I am trying to display an app for a 320x240 display.
Thanks
You can't really follow that example. It shows two different widgets depending on the orientation. Furthermore the doc warns about modifying size properties inside resizeEvent.
One solution would be to set a fix aspect ratio similar to 320x240 by overloading QWidget::heightForWidth. You wouldn't need to overload resizeEvent.
It will look like
int MainWindow::heightForWidth( int w ) {
return (w * 240 )/320;
}
heightForWidth is discussed in detail in https://stackoverflow.com/a/1160476/1122645.
edit:
sizeHint is used by the layout of the parent to compute the size of children widgets. In general, it make sense to implement it as
QSize MainWindow::sizeHint() const
{
int w = //some width you seem fit
return QSize( w, heightForWidth(w) );
}
but if MainWindow is top level then it will not change anything. You can also alter heightForWidth flag of your current size policy
QSizePolicy currPolicy = this->sizePolicy();
currPolicy->setHeightForWidth(true);
this->SetSizePolicy(currPolicy);
But again, if it is a top level widget I doesnt change much.
Anyway you don't need to call updateGeometry.
Related
I want to draw lines inside column that show possible connections between different signals(Further, I also want to make radiobuttons on them to choose what connections are active).
But now I have trouble that delegates allow me to SetItemDelegate only for all column or all row. So I can't just make different blocks of this lines like vertical line, corner lines, horizontal line and then paint them depending on data in cells. I attached an example image. What should I use to draw something like this?
Something like:
Define a new style, override drawPrimitive method and do custom painting?
Could you show me an example, please?
Lines example
What I have for now
My main code for creating rows with signals(I take them from .txt file for simulation for now):
int IPFilesize = IPfilespl.size();
ui->CompTab->setRowCount(IPFilesize);
for (int i = 0; i<IPFilesize; i++)
{
QWidget *ChBx = new QWidget();
QCheckBox *pCheckBox = new QCheckBox();
QHBoxLayout *pLayout = new QHBoxLayout(ChBx);
pLayout->addWidget(pCheckBox);
pLayout->setAlignment(Qt::AlignCenter);
pLayout->setContentsMargins(0,0,0,0);
ChBx->setLayout(pLayout);
ui->CompTab->setCellWidget(i, 0, ChBx);
//connect(ChBx,SIGNAL(clicked()),this,SLOT(checkboxClicked()));
}
for (int ii = 0; ii<IPFilesize; ii++)
{
ui->CompTab->setItem(ii, 2, new QTableWidgetItem(IPfilespl.at(ii)) );
//connect(ChBx,SIGNAL(clicked()),this,SLOT(checkboxClicked()));
}
ui->CompTab->setItemDelegateForColumn(1, new WireDelegateDown());
Header code
class WireDelegate: public QStyledItemDelegate { protected: void paint(QPainter* painter, const QStyleOptionViewItem& opt, const QModelIndex& index) const {
int x = opt.rect.x();
double y = opt.rect.y();
QPoint c = opt.rect.center();
double centerx = c.x();
double centery = c.y();
double r = opt.rect.right();
double width = opt.rect.width();
double height = opt.rect.height();
QPainterPath path;
path.addRect(centerx, centery-height/2, 5.0, height/2);
path.moveTo(0, 0);
path.addRect(centerx, centery, width/2, 5.0);
path = path.simplified();
painter->drawPath(path);
Your item delegate could be a subclass of QAbstractItemDelegate. Then you can set its type with a property like shapeType (or whatever you name it). Based on the shapeType, you can do internal painting stuff from within the reimplemented paint method.
void MyConnectionDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const
{
if (m_shapeType == ShapeType::horizontalLine) {
//..... Your fancy drawings happens here based on shapetype
} else if (m_shapeType == ShapeType::verticalLine) {
.
.
.
As I see in the picture (your desired result) it's not going to be simple and it can get quite complicated to implement such behavior. You will have to calculate the width, height, position of lines, colors, dots, arrows, nodes, etc for each delegate. When you exactly know which entities should be drawn in each cell, painting them using QPainter is a simple task.
You might consider whether QTableView is getting in the way more than it helps you. The built-in widgets are fantastic, but often, I've found that when I need to venture outside the realm of what they were specifically designed to do, I end up spending more time working around them than I get benefit. I don't know the right solution for what you're doing, but if it were me, I'd explore writing my own view based on QAbstractItemView and then just doing my own custom painting for the whole thing.
The downside of doing that is that QTableView provides a lot of interaction support for you, so if the interaction is a big benefit to you, then you have to write your own as well. So it's a trade-off. It's also a possibility that the built-in interaction for QTableView also gets in the way of what you're trying to do. It can go either way.
I'm developing a Qt Application and I'm trying to find a way to use QTextEdit as a label with long text without the scroll bar. In my ui I have a QScrollArea and inside of it I want to place a couple off QTextEdit widgets and I only want use scrolling inside QScrollArea. Problem is that no matter how I try to resize the QTextEdit it seems it has a maximum height and cuts of text, even if I set the size manually and QTextEdit::size returns the correct value.
I did the same thing with QLabel and it works fine, but in this case I need some methods that are only provided in QTextEdit.
I found this post:
Resizing QT's QTextEdit to Match Text Height: maximumViewportSize()
And the answer given was the following:
I have solved this issue. There were 2 things that I had to do to get
it to work:
Walk up the widget hierarchy and make sure all the size policies made
sense to ensure that if any child widget wanted to be big/small, then
the parent widget would want to be the same thing.
This is the main
source of the fix. It turns out that since the QTextEdit is inside a
QFrame that is the main widget in a QScrollArea, the QScrollArea has a
constraint that it will not resize the internal widget unless the
"widgetResizable" property is true. The documentation for that is
here: http://doc.qt.io/qt-4.8/qscrollarea.html#widgetResizable-prop.
The documentation was not clear to me until I played around with this
setting and got it to work. From the docs, it seems that this property
only deals with times where the main scroll area wants to resize a
widget (i.e. from parent to child). It actually means that if the main
widget in the scroll area wants to ever resize (i.e. child to parent),
then this setting has to be set to true. So, the moral of the story is
that the QTextEdit code was correct in overriding sizeHint, but the
QScrollArea was ignoring the value returned from the main frame's
sizeHint.
The problem is that I have no idea how to access the QTextEdit's QScrollArea to enable widgetResizable. Can anyone explain how I can achieve this or suggest a different way of resizing QTextEdit to perfectly fit it's content?
This will allow the height of the text box to change as required. You can edit the code a little to handle the width as well.
connect( m_textField, SIGNAL( textChanged() ), this, SLOT( onTextChanged() ) );
void MyClass::onTextChanged()
{
QSize size = m_textField->document()->size().toSize();
m_textField->setFixedHeight( size.height() + 3 );
}
Try this one :
QTextEdit textEdit;
textEdit.setHtml("<p>test test test test test test</p><p>|||||||||</p>");
textEdit.show();
textEdit.setFixedWidth(textEdit.document()->idealWidth() +
textEdit.contentsMargins().left() +
textEdit.contentsMargins().right());
Without a concrete example it's difficult to judge, but... it sounds as if you simply want a QTextEdit whose sizeHint depends on the current document size.
class text_edit: public QTextEdit {
using super = QTextEdit;
public:
explicit text_edit (QWidget *parent = nullptr)
: super(parent)
{
setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}
virtual QSize sizeHint () const override
{
QSize s(document()->size().toSize());
/*
* Make sure width and height have `usable' values.
*/
s.rwidth() = std::max(100, s.width());
s.rheight() = std::max(100, s.height());
return(s);
}
protected:
virtual void resizeEvent (QResizeEvent *event) override
{
/*
* If the widget has been resized then the size hint will
* also have changed. Call updateGeometry to make sure
* any layouts are notified of the change.
*/
updateGeometry();
super::resizeEvent(event);
}
};
Then use as...
QScrollArea sa;
sa.setWidgetResizable(true);
text_edit te;
te.setPlainText(...);
sa.setWidget(&te);
sa.show();
It appears to work as expected in the few tests I've done.
In ui i defined QTextEdit *textEdit object. I write it as height scalable-content :
int count = 0;
QString str = "";
// set textEdit text
ui->textEdit->setText("hfdsf\ncsad\nfsc\dajkjkjkjhhkdkca\n925");
str = ui->textEdit->toPlainText();
for(int i = 0;i < str.length();i++)
if(str.at(i).cell() == '\n')
count++;
// resize textEdit (width and height)
ui->textEdit->resize(ui->textEdit->fontMetrics().width("this is the max-length line in qlabel")
, ui->textEdit->fontMetrics().height() * (count + 2));
Notice : this work if you change QTextEdit font face or size! just in height scalable (before every thing set your QTextEdit frameShape to BOX).
if you want do width scalable-content, you should do these steps :
read QTextEdit(textEdit object) text as line to line
calculate every line length
select maximum of line length
use of QTextEdit::fontMetrics().width(QString str) for investigate str size in width
I hope this can help you...
Disclaimer: I am pretty much a beginner with QT.
I've been struggling for some time to rotate a QGraphicsView (no 3D rotation) but, despite what i do, it doesn't work. I have tried:
QTransform transform;
transform.rotate(45);
ui->graphicsView->setTransform(transform);
or more simply:
ui->graphicsView->rotate(45);
These seem like very straightforward ways to do it that should work, but for some reason, whenever i run it, the QGraphicsView doesn't rotate at all. If possible, i'd like some direct and easy to understand code snippets, and/or what i'm doing wrong.
EDIT: This is the code in the widget cpp file i have problems with. It should be a simple timer with an animated hourglass icon. It gets repeated every .5 seconds.
void Widget::timerEvent(QTimerEvent *event)
{
++timeFlag;
++timerFlag;
if (timerFlag < 115){
animateTimer = QString("\":/new/100/timerFrames/timerIconFrame%1.png\"").arg(timerFlag);
QPixmap pix(animateTimer);
pixmapitem.setPixmap(pix);
scene.addItem(&pixmapitem);
ui->graphicsView_2->setScene(&scene);
}
if (timerFlag >= 115 && timerFlag < 119){
//
}
if(timerFlag == 119){
ui->graphicsView_2->setStyleSheet("border-image:url(:/new/100/timerIconPix.PNG);border:0px;}");
}
if(timerFlag == 120){
timerFlag = 0;
}
if (timeFlag==2){
timeFlag = 0;
if(sec>=10){
ui->label_2->setText(QString("%1:%2").arg(min).arg(sec));
} else {
ui->label_2->setText(QString("%1:0%2").arg(min).arg(sec));
}
++sec;
if (sec == 60) {
sec = 0;
++min;
}
}
}
You're merely decorating the QGraphicsView using the style mechanism. You could have used a plain QWidget instead, since you don't use any graphics view functionality. None of the images in the stylesheet are what the view actually displays. The image must be on the scene displayed by the view.
Set the image on a QGraphicsPixmapItem, add that item to a scene, set the scene on the view, and then the transformations will work. You can then keep replacing the pixmap in the timer handler.
Finally, you must also check the timer id in the timerEvent. I assume that you're using a QBasicTimer, say called m_timer, you'd then check as follows:
void Widget::timerEvent(QTimerEvent * ev) {
if (ev->timerId() != m_timer.timerId()) return;
... // rest of the code
}
As you can see, the code that you've not included in the original question was absolutely essential! Without it, the question was wholly off-topic.
You need to implement a QGraphicsView, a QGraphicsScene and then add something that inherits from QGraphicsItem to that scene to rotate.
Here is an example that rotates a QWidget in a QGraphicsView:
QGraphicsView* view = new QGraphicsView(parent);
QGraphicsScene* scene = new QGraphicsScene(view);
view->setScene(scene);
// Widget to rotate - important to not parent it
QWidget* widget = new QWidget();
QProxyWidget proxy_widget = scene_->addWidget(widget);
QPropertyAnimation* animation = new QPropertyAnimation(proxy_widget, "rotation");
animation->setDuration(5000);
animation->setStartValue(0);
animation->setEndValue(360);
animation->setEasingCurve(QEasingCurve::Linear);
animation->start(QAbstractAnimation::DeleteWhenStopped);
I need to get the color of pixel under mouse, inside mouseMoveEvent of a QWidget (Breadboard). Currently I have this code->
void Breadboard::mouseMoveEvent(QMouseEvent *e)
{
QPixmap pixmap = QPixmap::grabWindow(winId());
QRgb color = pixmap.toImage().pixel(e->x(), e->y());
if (QColor(color) == terminalColor)
QMessageBox::information(this, "Ter", "minal");
}
Take a look at (scaled down) screenshot below-
When user moves his mouse on breadboard, the hole should get highlighted with some different color (like in red circle). And when the mouse exits, the previous color (grey) should be restored. So I need to do following steps-
Get color under mouse
According to color, floodfill the hole. (Different holes are distinguished using color)
On mouse out, restore the color. There would be wires going over holes, so I can't update the small rectangle (hole) only.
What is the fastest way of doing this? My attempt to extract color is not working i.e the Message box in my above code never displays. Moreover I doubt if my existing code is fast enough for my purpose. Remember, how fast you will be moving your mouse on breadboard.
Note - I was able to do this using wxWidgets framework. But due to some issues that project got stalled. And I am rewriting it using Qt now.
You are invited to look at code https://github.com/vinayak-garg/dic-sim
The "idiomatic" way of doing this in Qt is completely different from what you're describing. You'd use the Graphics View Framework for this type of thing.
Graphics View provides a surface for managing and interacting with a large number of custom-made 2D graphical items, and a view widget for visualizing the items, with support for zooming and rotation.
You'd define your own QGraphicsItem type for the "cells" in the breadboard that would react to hover enter/leave events by changing their color. The connections between the cells (wires, resistors, whatever) would also have their own graphics item types with the features you need for those.
Here's a quick and dirty example for you. It produces a 50x50 grid of green cells that become red when the mouse is over them.
#include <QtGui>
class MyRect: public QGraphicsRectItem
{
public:
MyRect(qreal x, qreal y, qreal w, qreal h)
: QGraphicsRectItem(x,y,w,h) {
setAcceptHoverEvents(true);
setBrush(Qt::green);
}
protected:
void hoverEnterEvent(QGraphicsSceneHoverEvent *) {
setBrush(Qt::red);
update();
}
void hoverLeaveEvent(QGraphicsSceneHoverEvent *) {
setBrush(Qt::green);
update();
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QGraphicsScene scene;
for (int i=0; i<50; i++)
for (int j=0; j<50; j++)
scene.addItem(new MyRect(10*i, 10*j, 8, 8));
QGraphicsView view(&scene);
view.show();
return app.exec();
}
You could modify the hover event handlers to talk to your "main window" or "controller" indicating what's currently under the mouse so you can update your caption, legend box or tool palette.
For best speed, render only the portion of the widget you're interested in into a QPaintDevice (like a QPixmap). Try something like this:
void Breadboard::mouseMoveEvent(QMouseEvent *e)
{
// Just 1 pixel.
QPixmap pixmap(1, 1);
// Target coordinates inside the pixmap where drawing should start.
QPoint targetPos(0, 0);
// Source area inside the widget that should be rendered.
QRegion sourceArea( /* use appropriate coordinates from the mouse event */ );
// Render it.
this->render(&pixmap, targetPos, sourceArea, /* look into what flags you need */);
// Do whatever else you need to extract the color from the 1 pixel pixmap.
}
Mat's answer is better if you're willing to refactor your application to use the graphics view API.
What I am trying to do is render a qwidget onto a different window (manually using a QPainter)
I have a QWidget (w) with a layout and a bunch of child controls. w is hidden. Until w is shown, there is no layout calculations happening, which is expected.
When I call w->render(painter, w->mapToGlobal(QPoint(0,0)), I get a bunch of controls all overlapping each other.
w->layout()->activate();w->layout()->update() doesn't seem to do anything.
Is there a way to force the layout to happen without showing w?
Forcing a layout calculation on a widget without showing it on the screen:
widget->setAttribute(Qt::WA_DontShowOnScreen);
widget->show();
The show() call will force the layout calculation, and Qt::WA_DontShowOnScreen ensures that the widget is not explicitly shown.
The layout calculation of a widget can be forced by calling invalidate() followed by activate() on its layout, even if the widget is hidden. This also causes the widget's size() and sizeHint() functions to return correct and updated values, even if show() has not yet been called on that widget.
It is however necessary to care about all child widgets and layouts recursively, as a layout recalculation request doesn't automatically propagate to the childs.
The following code shows how to do this.
/**
* Forces the given widget to update, even if it's hidden.
*/
void forceUpdate(QWidget *widget) {
// Update all child widgets.
for (int i = 0; i < widget->children().size(); i++) {
QObject *child = widget->children()[i];
if (child->isWidgetType()) {
forceUpdate((QWidget *)child);
}
}
// Invalidate the layout of the widget.
if (widget->layout()) {
invalidateLayout(widget->layout());
}
}
/**
* Helper function for forceUpdate(). Not self-sufficient!
*/
void invalidateLayout(QLayout *layout) {
// Recompute the given layout and all its child layouts.
for (int i = 0; i < layout->count(); i++) {
QLayoutItem *item = layout->itemAt(i);
if (item->layout()) {
invalidateLayout(item->layout());
} else {
item->invalidate();
}
}
layout->invalidate();
layout->activate();
}
Try with the QWidget::sizeHint() method, which is supposed to return the size of the widget once laid out.
I had some succes in a similar problem by first calling w->layout()->update() before w->layout()->activate(). That seems to force the activate() to actually do something rather than think it is fine because the window isn't being shown anyway.
When going through QWidget::grab() I noticed this part:
if (r.width() < 0 || r.height() < 0) {
// For grabbing widgets that haven't been shown yet,
// we trigger the layouting mechanism to determine the widget's size.
r = d->prepareToRender(QRegion(), renderFlags).boundingRect();
r.setTopLeft(rectangle.topLeft());
}
QWidget::grab() has been introduced in Qt 5.0, and this test function with a QDialog containing a layout seems to work on Qt 5.5.1
int layoutTest_2(QApplication& a)
{
CLayoutTestDlg dlg; // initial dlg size can also be set in the constructor
// https://stackoverflow.com/questions/21635427
QPixmap pixmap = dlg.grab(); // must be called with default/negative-size QRect
bool savedOK = pixmap.save("E:/temp/dlg_img.png");
// saving is not necessary, but by now the layout should be done
dlg.show();
return a.exec();
}
This worked for me when using the sizeHint() plus translating the painter, however I do this inside the paint() method.
void ParentWidget::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
painter->save();
painter->translate(option.rect.topLeft());
w->render(painter);
painter->restore();
}
In this case, option.rect.topLeft() gives me the correct placement. You should try a more sensible coordinate instead of w->mapToGlobal(QPoint(0,0).