I have a QPainter, and a rectangle.
i'd like to draw a QLineEdit control, empty. Just to draw it, not to have a live control. How do I do that? I have tried QStyle::drawPrimitive to no avail. nothing gets drawn.
QStyleOption option1;
option1.init(contactsView); // contactView is the parent QListView
option1.rect = option.rect; // option.rect is the rectangle to be drawn on.
contactsView->style()->drawPrimitive(QStyle::PE_FrameLineEdit, &option1, painter, contactsView);
Naturally, i'd like the drawn dummy to look native in Windows and OSX.
Your code is pretty close, but you would have to initialize the style from a fake QLineEdit. The following is based on QLineEdit::paintEvent and QLineEdit::initStyleOption.
#include <QtGui>
class FakeLineEditWidget : public QWidget {
public:
explicit FakeLineEditWidget(QWidget *parent = NULL) : QWidget(parent) {}
protected:
void paintEvent(QPaintEvent *) {
QPainter painter(this);
QLineEdit dummy;
QStyleOptionFrameV2 panel;
panel.initFrom(&dummy);
panel.rect = QRect(10, 10, 100, 30); // QFontMetric could provide height.
panel.lineWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth,
&panel,
&dummy);
panel.midLineWidth = 0;
panel.state |= QStyle::State_Sunken;
panel.features = QStyleOptionFrameV2::None;
style()->drawPrimitive(QStyle::PE_PanelLineEdit, &panel, &painter, this);
}
};
int main(int argc, char **argv) {
QApplication app(argc, argv);
FakeLineEditWidget w;
w.setFixedSize(300, 100);
w.show();
return app.exec();
}
Related
I'm going to deploy the qtvirtualkeyboard in my widget-based application like so:
#include <QtWidgets>
int main(int argc, char *argv[]) {
qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
QApplication app(argc, argv);
QMainWindow window;
QLineEdit input(&window);
input.move(250, 250);
window.show();
return app.exec();
}
But the only issue is that the virtual keyboard input panel hides the underlying widgets and cover them!
How should I achieve this?
Is there any document or solution for widgets-based applications?
you just need to add this line in main.cpp
qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
and will work Virtual Keyboard in Qtwidgets))
Finally got the solution!
You just need to call QGuiApplication::inputMethod() to get the application-wide Qt input method and then call QInputMethod::keyboardRectangle() and QInputMethod::isVisible() to get input method properties then remain a calculation based on your widget position and keyboard coordinate, here is a full-working sample to share:
lineedit.h:
class LineEdit :public QLineEdit {
Q_OBJECT
public:
LineEdit(QWidget *parent = nullptr);
LineEdit(const QString&, QWidget *parent = nullptr);
protected:
bool event(QEvent*) override;
private:
bool _moved = false;
int _lastDiff = 0;
};
lineedit.cpp:
LineEdit::LineEdit(QWidget *parent) :QLineEdit(parent) {
setAttribute(Qt::WA_InputMethodEnabled, true);
setInputMethodHints(inputMethodHints() | Qt::InputMethodHint::ImhDigitsOnly);
}
LineEdit::LineEdit(const QString& txt, QWidget *parent) : QLineEdit(txt, parent) {
setAttribute(Qt::WA_InputMethodEnabled, true);
setInputMethodHints(inputMethodHints() | Qt::InputMethodHint::ImhDigitsOnly);
}
bool LineEdit::event(QEvent* e) {
const auto keyboard_rect = QGuiApplication::inputMethod()->keyboardRectangle();
const auto keyboard_visible = QGuiApplication::inputMethod()->isVisible();
const auto global_y = QWidget::mapToGlobal(rect().topLeft()).y() + height();
const auto k_global_y = keyboard_rect.topLeft().y();
const auto diff = k_global_y - global_y;
const auto need_to_move = diff < 0;
/* move main widget */
if (keyboard_visible && !_moved && need_to_move) {
_moved = true;
_lastDiff = diff;
const auto g = parentWidget()->frameGeometry();
parentWidget()->move(g.x(), g.y() - qAbs(_lastDiff));
}
/* roll back */
if (!keyboard_visible && _moved) {
_moved = false;
const auto g = parentWidget()->frameGeometry();
parentWidget()->move(g.x(), g.y() + qAbs(_lastDiff));
}
return QLineEdit::event(e);
}
main.cpp:
#include <QtWidgets>
#define W 1024
#define H 768
int main(int argc, char *argv[]) {
qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
QApplication app(argc, argv);
QMainWindow window(nullptr, Qt::FramelessWindowHint);
LineEdit lineedit1(&window);
lineedit1.move(100, 450);
LineEdit lineedit2(&window);
lineedit2.move(100, 100);
window.resize(W, H);
window.show();
return app.exec();
}
results:
I want to draw a filled ellipse in QT that would not change its size when zooming in and out. For now I have the following:
QPen pen = painter->pen();
pen.setCosmetic(true);
pen.setWidth(5);
painter->setPen(pen);
QBrush brush = painter->brush();
brush.setStyle(Qt::SolidPattern);
painter->setBrush(brush);
painter->drawEllipse(p, 2, 2);
When I zoom out a gap between the boundary and the filling appear. So it looks like 2 concentric circles. And when I zoom in the filling overgrows the boundary and the disk gets bigger and bigger. Any idea how to fix this? Thanks!
I would instead look to the ItemIgnoresTransformations flag, which will make the item itself "cosmetic", rather than just the pen. Here's a working example:
#include <QtGui>
class NonScalingItem : public QGraphicsItem
{
public:
NonScalingItem()
{ setFlag(ItemIgnoresTransformations, true); }
QRectF boundingRect() const
{ return QRectF(-5, -5, 10, 10); }
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
QPen pen = painter->pen();
pen.setCosmetic(true);
pen.setWidth(5);
pen.setColor(QColor(Qt::red));
painter->setPen(pen);
QBrush brush = painter->brush();
brush.setStyle(Qt::SolidPattern);
painter->setBrush(brush);
painter->drawEllipse(QPointF(0, 0), 10, 10);
}
};
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QGraphicsScene *scene = new QGraphicsScene;
QGraphicsView *view = new QGraphicsView;
NonScalingItem *item = new NonScalingItem;
scene->addItem(item);
view->setScene(scene);
/* The item will remain unchanged regardless of whether
or not you comment out the following line: */
view->scale(2000, 2000);
view->show();
return app.exec();
}
I want to make the background of a QDialog transparent so that I can see through the window. I'm asking because I want to use a semi-transparent background image that creates a "rounded corner window" illusion. Using setOpacity is not an option for me because I want all widgets to remain at full opacity.
Is there a way to achieve this without resorting to native OS APIs?
Use QWidget::setAttribute(Qt::WA_TranslucentBackground);. Note that this also requires Qt::FramelessWindowHint to be set.
This example works for me:
#include <QtGui>
class Dialog : public QDialog
{
public:
Dialog() : QDialog(0, Qt::FramelessWindowHint) // hint is required on Windows
{
QPushButton *button = new QPushButton("Some Button", this);
setAttribute(Qt::WA_TranslucentBackground);
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Dialog d;
d.show();
return a.exec();
}
Regarding rounded corners, QWidget::setMask() will help you.
EDIT: In response to another question below in the comments, here is a working example that uses an image in a resources file, and that overrides QWidget::paintEvent():
#include <QtGui>
class Dialog : public QDialog
{
public:
Dialog() : QDialog(0, Qt::FramelessWindowHint) // hint is required on Windows
{
setFixedSize(500, 500); // size of the background image
QPushButton *button = new QPushButton("Some Button", this);
setAttribute(Qt::WA_TranslucentBackground);
}
protected:
void paintEvent(QPaintEvent *event)
{
QPainter painter(this);
painter.drawImage(QRectF(0, 0, 500, 500), QImage(":/resources/image.png"));
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Dialog d;
d.show();
return a.exec();
}
I have a Qt dialog and there is a slider in it, when the dialog is initialized the slider will be set a value. In order to remind the user what is the default value, I want to add a mark to the slider, just draw a line or a triangle above the handle. Here, the slider should be of QSlider type, that means I can't implement a customized control derived from QSlider. Is there any way to realize it ?
I'm not clear why you can't derive a control from QSlider. You can still treat it like a QSlider, just override the paintEvent method. The example below is pretty cheesy, visually speaking, but you could use the methods from QStyle to make it look more natural:
#include <QtGui>
class DefaultValueSlider : public QSlider {
Q_OBJECT
public:
DefaultValueSlider(Qt::Orientation orientation, QWidget *parent = NULL)
: QSlider(orientation, parent),
default_value_(-1) {
connect(this, SIGNAL(valueChanged(int)), SLOT(VerifyDefaultValue(int)));
}
protected:
void paintEvent(QPaintEvent *ev) {
int position = QStyle::sliderPositionFromValue(minimum(),
maximum(),
default_value_,
width());
QPainter painter(this);
painter.drawLine(position, 0, position, height());
QSlider::paintEvent(ev);
}
private slots:
void VerifyDefaultValue(int value){
if (default_value_ == -1) {
default_value_ = value;
update();
}
}
private:
int default_value_;
};
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
DefaultValueSlider *slider = new DefaultValueSlider(Qt::Horizontal);
slider->setValue(30);
QWidget *w = new QWidget;
QVBoxLayout *layout = new QVBoxLayout;
layout->addWidget(slider);
layout->addStretch(1);
w->setLayout(layout);
QMainWindow window;
window.setCentralWidget(w);
window.show();
return app.exec();
}
#include "main.moc"
Easiest way I can think off is:
Add QSlider to QSlider (like you do it with layouts and QFrames). Slider above will be your current slider (clickable one). Slider below will be your "default tick position" value.
#include <QApplication>
#include <QSlider>
#include <QVBoxLayout>
int main(int argc, char * argv[])
{
QApplication app(argc, argv);
QSlider * defaultValueSlider = new QSlider();
QSlider * valueSlider = new QSlider(defaultValueSlider);
QVBoxLayout * lay = new QVBoxLayout(defaultValueSlider);
lay->setContentsMargins(0, 0, 0, 0);
lay->setSpacing(0);
lay->addWidget(valueSlider);
defaultValueSlider->setRange(0, 100);
valueSlider->setRange(0, 100);
defaultValueSlider->setValue(30);
defaultValueSlider->show();
return app.exec();
}
Why do you need to inherit a QSlider to access its public methods?
http://doc.trolltech.com/4.7/qslider.html
You can just call its setTickPosition() in your app.
I'm having a Qt application with a main window that has five buttons aligned in a vertical order.
They all have the same size.
All I want to do is to increase the font size of the button label when the app goes fullscreen.
I would really appreciate a solution that does not need too much code ... was hoping that this was something that could be done in Qt Designer, but I couldn't find a way how to.
Any suggestions?
Best,
guitarflow
I can't think of any way to do it in designer, but it's really not too much code. Here's a quick-and-dirty proof of concept. You'd want to take into account margins (using QStyle::pixelMetrics and the like), but you get the idea.
#include <QtGui>
class FontAdjustingButton : public QPushButton {
public:
explicit FontAdjustingButton(QWidget *parent = NULL) : QPushButton(parent) {
setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
}
protected:
void resizeEvent(QResizeEvent *event) {
int button_margin = style()->pixelMetric(QStyle::PM_ButtonMargin);
QFont f = font();
f.setPixelSize(event->size().height() - button_margin * 2);
setFont(f);
}
};
int main(int argc, char **argv) {
QApplication app(argc, argv);
QWidget w;
QVBoxLayout *layout = new QVBoxLayout;
for (int i = 0; i < 5; ++i) {
FontAdjustingButton *btn = new FontAdjustingButton;
btn->setText(QString("Hello, world %1").arg(i));
layout->addWidget(btn);
}
w.setLayout(layout);
w.show();
return app.exec();
}