QPushButton from PNG with alpha overlayed on QGraphicsPixmapItem

marshaul

I am trying to draw a translucent button on top of a QGraphicsPixmapItem. My setup looks like this:

QIcon* playButtonIcon = new QIcon("/path/to/buttonImage.png");
QPushButton* m_playButton = new QPushButton;
m_playButton->setIcon(*m_playIcon);

QString frontPath = "/path/to/pixmap";
m_frontPixmap = new QPixmap(frontPath);
m_frontItem = new QGraphicsPixmapItem(*m_frontPixmap);

m_scene = new QGraphicsScene(-300,0,600,600, this);
this->setScene(m_scene);
m_scene->addItem(m_frontItem);
QGraphicsProxyWidget* gpw = m_scene->addWidget(m_playButton);

This renders the button on top of the pixmap, but instead of a transparent blackground I get a black box. So, either the alpha channel is being rendered as black or there is a black layer somewhere behind the QPushButton (but still in front of the pixmap).

I've tried applying transparency everywhere I can think to:

m_playButton->setStyleSheet("QPushButton{background-color: transparent;}"); // And a few other variants of this

QPalette button_palette(m_playButton->palette());
button_palette.setColor(QPalette::Button, Qt::color0);
m_playButton->setPalette(button_palette);

...to give a couple examples. Needless to say, none of these change (or resolve) the issue.

Does anybody know what's going on here? How to get what I want?

mrjj

Hi
Did you try
m_playButton ->setAttribute(Qt::WA_TranslucentBackground);

marshaul

@mrjj said in QPushButton from PNG with alpha overlayed on QGraphicsPixmapItem:

m_playButton ->setAttribute(Qt::WA_TranslucentBackground);

Yes, but no change. :(

SGaist

Hi,

Did you also try m_playButton->setStyleSheet("background: transparent; border: none") ?

In any case, depending on the look and feel you are wanting, you should consider implementing the controls also using QGraphicsItem.

marshaul

I have observed that

@SGaist said in QPushButton from PNG with alpha overlayed on QGraphicsPixmapItem:

Hi,

Did you also try m_playButton->setStyleSheet("background: transparent; border: none") ?

In any case, depending on the look and feel you are wanting, you should consider implementing the controls also using QGraphicsItem.

Yes, I basically came to the same conclusion. QPushButton is a convenience, except that in this case it isn't at all. I can draw the button and capture mouse click events any number of ways. I noticed that QLabel's transparency works here, but then I still need a QGraphicsProxyWidget. Why not cut out the middleman altogether?

Thanks.