How to draw rectangle with all corners rounded ?

JoeCFD

Something like this.

void myRect::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rect = QRectF(widget->rect());
    QPainterPath path;
    path->drawRoundedRect(rect, 10, 10); /* path not painter */
    auto copied_option = *option;
    copied_option.state &= ~QStyle::State_Selected;
    auto selected = option->state & QStyle::State_Selected;
    //QGraphicsRectItem::paint(painter, &copied_option, widget);  /* you do not call this one  */
    painter->save();
    if (selected) {
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(option->palette.windowText(), 0, Qt::SolidLine));
   }
   else {
       set pen color;
   }       
   painter->drawPath(path); 
   painter->restore();
}

tushu

@JoeCFD

I have used

painter.drawRoundedRect(rect, 10, 10);

because QPainterPath does not have drawRoundedRect()

current output

Below lines creating difference.

//QGraphicsRectItem::paint(painter, &copied_option, widget);  /* you do not call this one  */

JoeCFD

@tushu

void myRect::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rect = QRectF(widget->rect());
    QPainterPath path;
    path->addRoundedRect(rect, 10, 10); /* add not draw sorry */
    auto copied_option = *option;
    copied_option.state &= ~QStyle::State_Selected;
    auto selected = option->state & QStyle::State_Selected;
    //QGraphicsRectItem::paint(painter, &copied_option, widget);  /* drawing is finished here and no need to call parent->paint()  */
    painter->save();
    if (selected) {
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(option->palette.windowText(), 0, Qt::SolidLine));
   }
   else {
       set pen color;
   }       
   painter->drawPath(path); 
   painter->restore();
}

JoeCFD

@tushu You also need to try the example first

void myRect::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
painter->setRenderHint(QPainter::Antialiasing);
QPainterPath path;
path.addRoundedRect(QRectF(10, 10, 100, 50), 10, 10);
QPen pen(Qt::black, 10);
painter->setPen(pen);
painter->fillPath(path, Qt::red);
painter->drawPath(path);
}

tushu

@JoeCFD
For this , getting the same above output.
(i.e. No border of any rectangle)

JoeCFD

@tushu did you try the example?

tushu

@JoeCFD

Example's output

I have just removed

//painter->fillPath(path, Qt::red);

tushu

@JoeCFD
Is the below line correct ?

QRectF rect = QRectF(widget->rect());

because of the above line , it is creating bigger rectangle ?
But bigger rectangle ( outermost ) has curved corner.

JoeCFD

@tushu you know the size of your rects, right? I do not know.

tushu

@JoeCFD
Your rectangle size suggestion worked.
Current output.

Now I want to round corner of middle 5 rectangle only ( i.e. sw1,sw2,PD_blue, PD_green,PD_yellow)
But left side rectangle ( small ) also got changed and looking like circle.

I think, I will need to set some flag and will have to decide, which rectangle's corner should be rounded.

But now main concern is PD_blue, PD_green,PD_yellow rectangles color is not visible.

I set their color, after creating rectangle using setBrush(). I do not set their color in paint(). After creating rectangle, if they are full filling some criteria, then I set color on them.

Why that color is not visible ?

Here is my paint()

void guiSchematicRect::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(option);
    Q_UNUSED(widget);
    QRectF rect = QRectF(_polyRect);
    QPainterPath path;
    path.addRoundedRect(rect, 4, 4);
   auto copied_option = *option;
    copied_option.state &= ~QStyle::State_Selected;
    auto selected = option->state & 
   QStyle::State_Selected;
    painter->save();
    if (selected) {
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(option->palette.windowText(), 1, Qt::SolidLine));
   }
   else {
       painter->setPen(Qt::blue);
   }
   painter->drawPath(path);
   painter->restore();
}

mpergand

@tushu said in How to draw rectangle with all corners rounded ?:

if they are full filling some criteria, then I set color on them.
Why that color is not visible ?

fill your form first:
painter->fillPath(path, yourColor);

tushu

@JoeCFD
If I add below line in paint() , then I get my 3 rectangle ( PD_blue, PD_green, PD_yellow) with thier respective color.

QGraphicsRectItem::paint(painter, &copied_option, widget);

BUt output I get like this :

Can you see the corners ? There is a round shape but it is getting overlapped.

What is the issue with this line ?

QGraphicsRectItem::paint(painter, &copied_option, widget);

With this I get color of remaining rectangle but could not see round shape at edge.

JoeCFD

@tushu QGraphicsRectItem::paint(painter, &copied_option, widget); is to call the parent to paint the rect without round corners. Look at the example and this call is not needed.

tushu

@JoeCFD
You are correct.
But now problem is, after creating rectangle, for some of the rectangle, I am setting some colour with

SetBrush()

And the color applied with above method, is not visible to the rectangle. They are appearing colorless.

Can we use paint() parameter in this case ?

paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

Or is there any other way to solve this issue ?

JoeCFD

@tushu can you show your full code of this func?

tushu

@JoeCFD

myRect.h

class myRect : public QGraphicsRectItem 
{
      explicit myRect(QRectF &rectPoints, QGraphicsScene *_scene, QGraphicsItem *parent = nullptr) : QGraphicsRectItem(rectPoints, parent),  _scene(_scene)
    {}
}

myRect.cpp

void myRect::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(widget);
    QRectF rect = QRectF(_polyRect);
    QPainterPath path;
    path.addRoundedRect(rect, 4, 4);

    auto copied_option = *option;
    copied_option.state &= ~QStyle::State_Selected;
    auto selected = option->state & QStyle::State_Selected;
    painter->save();
    if (selected) {
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(option->palette.windowText(), 0, Qt::SolidLine));
    }
    else
         painter->setPen(Qt::blue);
    painter->drawPath(path);
    painter->restore();
}

void myRect::CreateRect(QRectF rect)
{
    this->_polyRect = rect;
    QPen mPen;
    mPen.setWidth(1);
    mPen.setBrush(Qt::blue);
    this->setPen(mPen);
    this->setFlag(QGraphicsItem::ItemIsSelectable);
}

mySymbol.cpp

DrawSymbol()
{
   QRectF Rect( co-ordinates );
    myRect* rect = new myRect(Rect, _scene);
     rect->CreateRect(Rect);
    if( if it is power domain ) 
      CreatePD(rect);
}

CreatePD(myRect* rect)
{
    QColor pdColor{some color };
    rect->setBrush(pdColor);
}

Note : If I add following line in paint()

QGraphicsRectItem::paint(painter, &copied_option, widget);

then I can see my rectangle with color. But gets problem with rounded corner.

JoeCFD

@tushu Check the example and @mpergand's reply. You do not have
painter->fillPath(path, yourColor);
Try to set yourColor = Qt::green to see what you get.

tushu

@JoeCFD
Your suggestion worked.
Thanks for help !

tushu

@mpergand
Your solution worked.
Thanks for help !

tushu

@JoeCFD @mpergand
I am facing another small issue in paint()

When I left click on any rectangular object, it's paint() runs. And it highlights that object perfectly.

But when I right click on object ( I have few Right mouse button options ) , paint() method runs, but it does not highlight that object.

Her is my paint()

void myRect::paint(QPainter *painter, QPainterPath path,
                                            const QStyleOptionGraphicsItem *option)
{
    auto copied_option = *option;
    copied_option.state &= ~QStyle::State_Selected;
    auto selected = option->state & QStyle::State_Selected;
    if(selected)
        qDebug()<<"TRUE ";
    else
        qDebug()<<"FALSE ";
    painter->save();
    if (selected) {
        qDebug()<<"In selected ";
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(option->palette.windowText(), 1, Qt::SolidLine));
        qDebug()<<"Selected completing  ";
    } else
    {
        painter->setPen(Qt::blue);
        qDebug()<<"NOT Selected";
    }
    painter->drawPath(path);
    painter->restore();
}

I checked through qDebug statements, and I found that,

auto selected

variable has value false on Right click.( i.e. selected = false)

On left click, It works perfectly ( i.e. selected = true )