Want to implement rectangle movements similar to in microsoft power point in my QGraphicsView

Devopia53

If you want another way, do the following:

[...]
#include <QGraphicsRectItem>

class MyRectItem : public QGraphicsRectItem
{
public:
    explicit MyRectItem(QGraphicsItem *parent = 0);

    // QGraphicsItem interface
protected:
    virtual void keyPressEvent(QKeyEvent *event) override;
};

[...]

void MyRectItem::keyPressEvent(QKeyEvent *event)
{
    if (!flags().testFlag(QGraphicsItem::ItemIsMovable))
        return;

    if (!isSelected())
        return;

    switch (event->key()) {
        case Qt::Key_Left:  moveBy(-1, 0);  break;
        case Qt::Key_Right: moveBy(1, 0);   break;
        case Qt::Key_Up:    moveBy(0, -1);  break;
        case Qt::Key_Down:  moveBy(0, 1);   break;
    }
}

[...]
auto    item = new MyRectItem;
item->setRect(QRectF(-100, -100, 100, 100));
item->setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable | QGraphicsItem::ItemIsFocusable);
graphicsView->scene()->addItem(item);
[...]

Qt Enthusiast

In this I am not sure how to edit the locaation of existing rectangle. are you saying you are removing the previous rectangle

Qt Enthusiast

@Devopia53 In this I am not sure how to edit the locaation of existing rectangle. are you saying you are removing the previous rectangle

reply

J.Hilk

@Qt-Enthusiast
@Devopia53 pretty much wrote it out for you. Instead of the default QGraphicsItem you use the custom class MyRectItem he defined for you.

the last section between the 2 [...] even show you how to add a MyRectItem to your graphicsView.

Not much else can be done here

Qt Enthusiast

One more question If I have pressed Shift + Up key what should be value of event->key()

J.Hilk

@Qt-Enthusiast

Key Press event don't come simultaneously, so reimplement KeyReleaseEvent as well, to check if a shift key was pressed and relesed or is still pressed and adjust your KeyPress event accordingly

Qt Enthusiast

A small code will be helpful again

J.Hilk

@Qt-Enthusiast

//MyRectItem .h
private:
bool bShiftPressed = false;

protected:
    virtual void keyReleaseEvent(QKeyEvent *event) override;

//MyRectItem .cpp

void MyRectItem::keyPressEvent(QKeyEvent *event)
{
    if (!flags().testFlag(QGraphicsItem::ItemIsMovable))
        return;

    if (!isSelected())
        return;

if(!bShiftPressed)
    switch (event->key()) {
        case Qt::Key_Left:  moveBy(-1, 0);  break;
        case Qt::Key_Right: moveBy(1, 0);   break;
        case Qt::Key_Up:    moveBy(0, -1);  break;
        case Qt::Key_Down:  moveBy(0, 1);   break;
        case Qt::Key_Shift: bShiftPressed = true;
    }
else
    switch (event->key()) {
        case Qt::Key_Left:  moveBy(-10, 0);  break;
        case Qt::Key_Right: moveBy(10, 0);   break;
        case Qt::Key_Up:    moveBy(0, -10);  break;
        case Qt::Key_Down:  moveBy(0, 10);   break;
    }
}

void MyRectItem::keyReleaseEvent(QKeyEvent *event){
   if(event->key() == Qt::Key_Shift)
       bShiftPressed =false;
}

Qt Enthusiast

I this case up and down arrow key are associated with scrollbar movment . If there is scrollbar movement , then these macros does =move but scrollbar is still moveBy works

Any suggestions on how to avoid this issue

jsulm

@Qt-Enthusiast said in Want to implement rectangle movements similar to in microsoft power point in my QGraphicsView:

I this case up and down arrow key are associated with scrollbar movment . If there is scrollbar movement , then these macros does =move but scrollbar is still moveBy works

Could you please rephrase this? I really cannot understand what you mean.

Qt Enthusiast

In my case the UP key moves the scrollbar up ,

but with Shift+Up key with the code you suggested the Shift+key moves the scroll bar up not the object

in this action on Up takes precedence on action on other key . COuld you let me know what should be done

Qt Enthusiast

To have only one action on Shift+UP key I have put return in Key_UP case in the following code https://paste.ofcode.org/9kgHwu2FBRiWvQsQpryu3f. As I i undesstand the Shift+Up will override on the key press event binding . Is that OK ?

Do you see problem in the following code

https://paste.ofcode.org/9kgHwu2FBRiWvQsQpryu3f

J.Hilk

@Qt-Enthusiast

From my brief overview, it looks good.

Just one thing, try not to use qt's foreach makro, it will be deprecated soon in Qt 5.9 or later.

Better to adjust now than revisit all your code when you updated :)