Visual bug when using show() on a widget above a QPushButton

[SoftEngi]

Hey everyone, I've been trying to solve this for hours now... Here is what I'm trying to do:

My main window has a QPushButton, when you click on it an hidden widget appears above all the other widgets. The newly shown widget contains a single QWidget displaying an image. The problem is, the QPushButton seems to interfer with the QWidget display. Here is the result:

!http://oi57.tinypic.com/111qo84.jpg(Visual bug - before resize)!

Something interesting to note, after resize, the display corrects itself:

!http://oi57.tinypic.com/125t98j.jpg(Display corrected - after resize)!

Here is my code (window.cpp and imagelabel.cpp are probably the only important files, but I've put all others if you want to compile it yourself):

main.cpp

@#include <QApplication>
#include <QtWidgets>
#include "window.h"

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

Window w;
w.show();

return app.exec();

}@

window.h
@#ifndef WINDOW
#define WINDOW

#include <QtWidgets>
#include <string>
#include <QVBoxLayout>
#include <QFrame>
#include <QDebug>

#include "imagelabel.h"

class Window : public QMainWindow
{
Q_OBJECT

public:
Window();

void resizeEvent(QResizeEvent *event);
void moveEvent(QMoveEvent *event);

private:
QWidget *centralWidget;
QVBoxLayout *mainLayout;
QVBoxLayout *overlayLayout;
QWidget *cardPicker;

};

#endif // WINDOW@

imagelabel.h
@#ifndef IMAGELABEL
#define IMAGELABEL

#include <QWidget>
#include <QPainter>
#include <QPaintEvent>
#include <QDebug>

class ImageLabel : public QWidget
{
Q_OBJECT

public:
explicit ImageLabel(QWidget parent = 0);
const QPixmap pixmap() const;

public slots:
void setPixmap(const QPixmap&);

protected:
void paintEvent(QPaintEvent *);

private:
QPixmap pix;
};

#endif // IMAGELABEL@

imagelabel.cpp
@#include "imagelabel.h"

ImageLabel::ImageLabel(QWidget *parent) :
QWidget(parent)
{
}

void ImageLabel::paintEvent(QPaintEvent *event)
{
QWidget::paintEvent(event);

if (pix.isNull())
    return;

QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);

QSize pixSize = pix.size();
pixSize.scale(event->rect().size(), Qt::KeepAspectRatio);

QPixmap scaledPix = pix.scaled(pixSize,
                               Qt::KeepAspectRatio,
                               Qt::SmoothTransformation
                               );

painter.drawPixmap(QPoint(), scaledPix);

}

const QPixmap* ImageLabel::pixmap() const
{
return &pix;
}

void ImageLabel::setPixmap (const QPixmap &pixmap)
{
pix = pixmap;
}
@

window.cpp
@#include "window.h"

Window::Window()
{
setMinimumSize(475, 325);

centralWidget = new QWidget;
setCentralWidget(centralWidget);

// Default central widget
mainLayout = new QVBoxLayout(centralWidget);

// Main application buttons
QPushButton *openCPButton = new QPushButton("Open CardPicker");
QPushButton *quitButton = new QPushButton("Quit");
QObject::connect(quitButton, SIGNAL(clicked()), qApp, SLOT(quit()));

mainLayout->addWidget(openCPButton);
mainLayout->addWidget(quitButton);


// The pop up widget that appears when "openCPButton" is clicked
cardPicker = new QWidget(centralWidget);
cardPicker->hide();

QObject::connect(openCPButton, SIGNAL(clicked()), cardPicker, SLOT(show()));

overlayLayout = new QVBoxLayout(cardPicker);
QWidget *m_cpFrame = new QLabel();
m_cpFrame->setStyleSheet(" QLabel { background-color : white;"
               "color : blue; border: 2px solid black;}");

overlayLayout->addWidget(m_cpFrame);

QVBoxLayout *cardsLayout = new QVBoxLayout(m_cpFrame);
ImageLabel *card = new ImageLabel();
card->setPixmap(QPixmap("Images/cards/2c.png"));

cardsLayout->addWidget(card);

QPushButton *closeCPButton = new QPushButton("Close");
QObject::connect(closeCPButton, SIGNAL(clicked()), cardPicker, SLOT(hide()));
cardsLayout->addWidget(closeCPButton);

}

void Window::resizeEvent(QResizeEvent *event)
{
cardPicker->resize(this->width()*0.9, this->height()*0.6);
event->accept();
}

void Window::moveEvent(QMoveEvent *)
{
cardPicker->move(width()*0.05, height()*0.2);
}
@

I've tried this code on multiples compilers and it's always the same. I'm on Windows 8.1, Qt5.4.0. Thanks for your help!

[SGaist]

Hi,

Maybe a silly question but why don't you use QLabel ?

[SoftEngi]

I needed to resize my image and keep its aspect ratio. When I googled that I ended up finding this stackoverflow question and answer:

"How do I make an image resize to scale in Qt?":http://stackoverflow.com/questions/14107144/how-do-i-make-an-image-resize-to-scale-in-qt

The code seemed to make sense, and while the display bug probably comes from there, I'm not sure what I should change nor why is it not working?

[SGaist]

Does it also happen if you run your card picker solo ?