How to draw over QLabel in Qt - qt

Question

I have to create one screen in Qt in which I have to show a remote having lots of buttons in it and when user clicks some button on actual remote, corresponding button in the image get highlighted. So what I have done is, I have used QLabel and set the remote image as background image and then I have put small rectangular label for each button and filled them with semi transparent color and when user click button in actual remote label color changes, but by using this method lot of labels are getting used making code looking inefficient, so I was thinking of drawing on QLabel (which has a remote as background image) over buttons.
Can anybody suggest me, which API of Qt should I use, and how to follow up on this?

Answer 1

I believe QGraphics is the correct route for a completely custom graphical interface, but if you want to try something that doesn't require you to change too much of your existing approach, you can do a widget with a custom paint event:
This is written in PyQt but you can easily translate to Qt
from PyQt4 import QtCore, QtGui
class LabelButton(QtGui.QWidget):
clicked = QtCore.pyqtSignal()
def __init__(self, labelStr, pixStr, parent=None):
super(LabelButton, self).__init__(parent)
self.label = labelStr
self.pix = QtGui.QPixmap(pixStr)
def paintEvent(self, event):
super(LabelButton, self).paintEvent(event)
rect = event.rect()
painter = QtGui.QPainter(self)
painter.drawPixmap(rect, self.pix)
pos = (rect.bottomLeft()+rect.bottomRight()) / 2
pos.setY(pos.y()-10)
painter.drawText(pos, self.label)
painter.end()
def mousePressEvent(self, event):
event.accept()
self.clicked.emit()
def handleClick():
print "CLICK"
if __name__ == "__main__":
app = QtGui.QApplication([])
widget = LabelButton("A Text Label", "myImage.png")
widget.resize(600,400)
widget.show()
widget.raise_()
widget.clicked.connect(handleClick)
app.exec_()
This is a rough example. You can get more fine tuned with the drawing of the text. This widget takes a label string, and a picture path, and will paint the picture as the background, and the text as a label. You can do any number of things with this custom widget in both the paint event, and with custom signals and events.

Answer 2

I have used this code to Draw over Image in Label:
Image is loaded in Ui and the Code is as follows In paintevent
void ColorTab::paintEvent(QPaintEvent *e){
ui->lbl_capture_img->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
ui->Lbl_color_tab_WG->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
Cap_Image = QImage(ui->lbl_capture_img->pixmap()->toImage());
Lbl_Image = QImage(ui->Lbl_color_tab_WG->pixmap()->toImage());
QPainter painter_Lbl(&Lbl_Image);
QPainter painter_Cap(&Cap_Image);
QPen pen(Qt::white, 5, Qt::DotLine, Qt::RoundCap, Qt::RoundJoin);
painter_Lbl.setPen(pen);
painter_Cap.setPen(pen);
painter_Lbl.drawPolygon(blinkRect_Lbl);
painter_Cap.drawPolygon(blinkRect_Cap);
ui->lbl_capture_img->setPixmap(QPixmap::fromImage(Cap_Image));
ui->Lbl_color_tab_WG->setPixmap(QPixmap::fromImage(Lbl_Image));
painter_Cap.end();
painter_Lbl.end();
}