What is the meaning of the label in the yellow rectangle? How to remove (hide) it?
I'm working with Qwt 6.0.1 and Qt 4.8.6
I've found, looking deep in the code, that the label is not part of a standard QwtPlot. It's a custom label and it's created using the following method of the QwtText class:
void draw( QPainter *painter, const QRectF &rect ) const;
Pseudo-code:
void MyQwtPlot::drawCustomLabel()
{
QPainter painter(this);
QwtText label(<label-text>);
label.draw(&painter, QRectF(<label-position>));
painter.end();
}
where MyQwtPlot is a class that extends QwtPlot.
I've solved commenting the drawCustomLabel method in my implementation.
Related
I am designing a timer with Qt. With QGraphicsEllipseItem, I drew a circle and now I need to animate the QPen around this circle (change color) every second. I found QGraphicsPathItem, but I need some examples on how to move forward. Can anyone show me an example?
You have two problems:
QGraphicsEllipseItem is not a QObject so QPropertyAnimation can't be used directly on this item
QGraphicsItemAnimation doesn't cover property you want to animate.
What you can do?
IMO best approach is to provide some custom QObject on which you could do this animation. You can inherit QObject or use fake QGraphicsObject (which is a QObject).
class ShapeItemPenAnimator : public QGraphicsObject {
Q_OBJECT
private:
QAbstractGraphicsShapeItem *mParent;
QPropertyAnimation *mAnimation;
public:
QPROPERTY(QColor penColor
READ penColor
WRITE setPenColor)
explicit ShapeItemPenAnimator(QAbstractGraphicsShapeItem * parent)
: QGraphicsObject(parent)
, mParent(parent) {
setFlags(QGraphicsItem::ItemHasNoContents);
mAnimation = new QPropertyAnimation(this, "penColor", this);
}
QColor penColor() const {
return mParent->pen().color();
}
public slots:
void setPenColor(const QColor &color) {
QPen pen(mParent->pen());
pen.setColor(color);
mParent->setPen(pen);
}
public:
void paint(QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget = 0) {
}
QRectF boundingRect() const {
return QRectF();
}
QPropertyAnimation *animation() const {
return mAnimation;
}
}
Now you just attach this object to your QGraphicsEllipseItem and set animation you need.
// yourEllipse
ShapeItemPenAnimator *animator = new ShapeItemPenAnimator(yourEllipse);
animator->animation()->setEndValue(....);
animator->animation()->setStartValue(....);
animator->animation()->setDuration(....);
animator->animation()->setEasingCurve(....);
There are several classes helping with animations of QGraphicsItem in Qt. I suggest looking into QGraphicsItemAnimation and QPropertyAnimation. You can use the second one to animate the color of an item. Here is an example of using QPropertyAnimation:
How to make Qt widgets fade in or fade out?
I currently working on a text editor using Qtextedit and I want to Draw a shapes like triangle, square and ellipse… etc in the editor to Richness the document.
So I was wondering if is it possible to do this with Qtextedit and only Qtextedit.
Actually I am new to Qt so any ideas any tutorial any links would be highly appreciated
Thanks in advance and sorry for my english.
Best regards.
Sure it's possible, if I understand you correctly. All you need is just implement your own TextEdit derived from QTextEdit and reimplement paintEvent()
For example:
QMyTextEdit.h
class QMyTextEdit : public QTextEdit
{
public:
QMyTextEdit(QWidget *parent = 0);
protected:
void paintEvent(QPaintEvent * event);
};
QMyTextEdit.cpp
QMyTextEdit::QMyTextEdit(QWidget *parent) :
QTextEdit(parent)
{
}
void QMyTextEdit::paintEvent(QPaintEvent *event)
{
QTextEdit::paintEvent(event);
QPainter painter(viewport());
QPen pen;
pen.setColor(Qt::blue);
pen.setWidth(2);
painter.setPen(pen);
painter.setRenderHint(QPainter::Antialiasing, true);
QPoint center = viewport()->rect().center();
painter.drawRect(center.x() - 10,center.y() - 10,20,20);
}
I am attempting to spawn a custom QGraphicsItem inside my scene, but am unsure of how exactly to map the point from its origin to the Item. My location comes from a dropEvent in my MainWindow:
void MainWindow::dropEvent(QDropEvent *event)
{
QPointF dropPos = ui->GraphicsView->mapFrom(this, event->pos());
vModule *module = new vModule(dropPos);
ui->GraphicsView->scene->addItem(module);
}
This is my vModule.cpp:
vModule::vModule(QPointF dropPos)
{
QPointF pos = mapFromScene(dropPos);
setX(pos.x());
setY(pos.y());
// ...
}
// Event handler implementation, shouldn't be relevant
And my vModule.h:
class vModule : public QObject, public QGraphicsItem
{
public:
explicit vModule(QPointF dropPos);
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
QRectF boundingRect() const;
protected:
void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
void mousePressEvent(QGraphicsSceneMouseEvent *event);
}
This is the closest to what I logically thought the conversion would be, but it is quite wrong in practice, more wrong than simply passing the position from the event as-is (which is a constant difference in position from the main window?). Can anyone correct my error?
In the constructor of vModule, you're calling mapFromScene before the widget has even been added to the scene.
Add the Widget first then set its position. Also, if you think about it, you're going from global (screen) coordinates to local widget coordinates. This function may be of use, assuming the drop event coordinates are in screen space: -
QPoint QWidget::mapFromGlobal(const QPoint & pos) const
which Qt help defines as: -
Translates the global screen coordinate pos to widget coordinates.
I want to be able to paint on top of my application's window so that I can annotate all the widgets with some extra diagnostic information, similar to the CSS developer tools in Firefox (eg add widget classes, styles, highlight borders etc).
I can walk the widget tree and extract the relevant information, but the question is how can I overlay all the application windows with this information?
One way would be to override my QMainWindow's paint event, but this has to be done for all top level windows. Is there an alternative method where you can paint on the QDesktopWidget for instance? Or any hooks into each QWidget's paint method? Anything that involves subclassing QWidget itself won't work with the standard widgets.
This follows on from my previous question:
Are there any useful tools for diagnosing Qt layout and spacing problems?
cheers
Mandrill
EDIT:
Thanks to Dmitry I've now got a really simple method that is easily extensible:
class DiagnosticStyle : public QWindowsVistaStyle
{
Q_OBJECT
public:
typedef QWindowsVistaStyle BaseStyle;
void drawControl(ControlElement element, const QStyleOption* option, QPainter* painter, const QWidget* widget) const;
};
void DiagnosticStyle::drawControl(ControlElement element, const QStyleOption* option, QPainter* painter, const QWidget* widget) const
{
BaseStyle::drawControl(element, option, painter, widget);
if (widget && painter) {
// draw a border around the widget
painter->setPen(QColor("red"));
painter->drawRect(widget->rect());
// show the classname of the widget
QBrush translucentBrush(QColor(255,246,240, 100));
painter->fillRect(widget->rect(), translucentBrush);
painter->setPen(QColor("darkblue"));
painter->drawText(widget->rect(), Qt::AlignLeft | Qt::AlignVCenter, widget->metaObject()->className());
}
}
qApp->setStyle(new DiagnosticStyle());
You can create own style class based on QMotifStyle or other ... and paint on any widget/control related to him information.
void MyStyle::drawPrimitive(PrimitiveElement element, const QStyleOption *option,QPainter *painter, const QWidget *widget) const
{
QStyle::State flags = option->state;
QRect rect = option->rect;
QPalette pal = option->palette;
QBrush brush;
switch (element)
{
case PE_FrameTabWidget:
{
painter->save();
// for example: draw anything on TabWidget
painter->drawPixmap(rect,centerPm,centerPm.rect());
painter->restore();
}
break;
default:
QMotifStyle::drawPrimitive(element, option, painter, widget);
break;
}
}
Somewhere in Qt5 the styles (GTK, Windows, etc) were made internal. Now you need to use QCommonStyle.
If anyone's wondering how to do this with Qt5+. Here's a self-contained version of #the_mandrill's code above.
class DiagnosticStyle : public QCommonStyle
{
Q_OBJECT
public:
typedef QStyle BaseStyle;
void drawControl(ControlElement element, const QStyleOption* option, QPainter* painter, const QWidget* widget) const
{
QCommonStyle::drawControl(element, option, painter, widget);
if (widget && painter) {
// draw a border around the widget
painter->setPen(QColor("red"));
painter->drawRect(widget->rect());
// show the classname of the widget
QBrush translucentBrush(QColor(255,246,240, 100));
painter->fillRect(widget->rect(), translucentBrush);
painter->setPen(QColor("darkblue"));
painter->drawText(widget->rect(), Qt::AlignLeft | Qt::AlignVCenter, widget->metaObject()->className());
}
};
};
Then, in your main window constructor call
qApp->setStyle(new DiagnosticStyle());
I'm trying to create custom widget inheriting QFrame. All works fine, but I'm unable to draw the focus rectangle around my widget. Below is the sample code I use for drawing:
frame.h
class Frame : public QFrame {
Q_OBJECT
public:
Frame(QWidget *parent = 0);
~Frame();
protected:
void paintEvent(QPaintEvent *event);
private:
Ui::Frame *ui;
};
frame.cpp
Frame::Frame(QWidget *parent) :
QFrame(parent),
ui(new Ui::Frame)
{
ui->setupUi(this);
setFocusPolicy(Qt::ClickFocus);
}
Frame::~Frame()
{
delete ui;
}
void Frame::paintEvent(QPaintEvent *event)
{
QFrame::paintEvent(event);
if (hasFocus()) {
QStylePainter painter(this);
QStyleOptionFocusRect option;
option.initFrom(this);
option.backgroundColor = palette().dark().color();
painter.drawPrimitive(QStyle::PE_FrameFocusRect, option);
}
}
What I mean by 'unable to draw focus frame' is that when you click a standard widget that accepts focus (let's say QLineEdit), it has a blue rectangle drawn around it. When I click my widget there is no such rectangle drawn. Are there any more things I should do besides setting focusPolicy on my widget?
It might have something to do with the style your app is using. When I try your code with the "gtk" and "cleanlooks" style, no focus rectangle is drawn. With "plastique" and "windows" it is. Since I'm on Linux, I cannot test "windowsxp" and "macintosh". Try running with the -style option and see what happens.
try also
setFocusPolicy(Qt::StrongFocus);
setAttribute( Qt::WA_MacShowFocusRect);