CODEWITHSUNDEEP
c++qt
KelvinS
KelvinS

Reputation: 3061

How to create a QWidget with a triangle shape?

How can I create a QWidget with a triangle shape?

It needs to be a QWidget because it will be included inside another widget, must be clickable and will perform some animations (but at this first time I just need to create the triangle shape).

Something like this:

enter image description here

I'm using Qt 5.3

Upvotes: 3

Views: 854

Answers (1)

StPiere
StPiere

Reputation: 4243

Here one example. hope it helps.

widget.h:

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPainterPath>
#include <QPoint>
#include <QVector>

class Widget : public QWidget
{
  Q_OBJECT

public:
  Widget(QWidget *parent = 0);
  ~Widget();

protected:
  void paintEvent(QPaintEvent *event) override;

private:
  QPainterPath getPath() const;
  QRegion getRegion() const;

private:
  int width = 100;
  int height = 100;
  QVector<QPoint> points;
};

#endif // WIDGET_H

widget.cpp:

#include "widget.h"
#include <QPainter>
#include <QPoint>
#include <QPainterPath>
#include <QBrush>
#include <QPolygon>
#include <QVector>

Widget::Widget(QWidget *parent)
  : QWidget(parent),
    points(3)
{
    points[0] = QPoint(20, 20);
    points[1] = QPoint(80, 20);
    points[2] = QPoint(50, 80);

    setFixedSize(width, height);   
    setMask(getRegion());
}

Widget::~Widget()
{

}

QPainterPath Widget::getPath() const
{
    QPainterPath path;
    path.moveTo(points[0]);
    path.lineTo(points[1]);
    path.lineTo(points[2]);
    path.lineTo(points[0]);

    return path;
}

QRegion Widget::getRegion() const
{
  return QRegion(QPolygon(points));
}

void Widget::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);

    QPainterPath path = getPath();

    QPainter painter(this);
    painter.setPen(Qt::NoPen);
    painter.fillPath(path, QBrush(Qt::black));
}

Upvotes: 3

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