Incorrect Bounding Rect?

[CJha]

Hi, I have a code to generate a label for axis:

void npi::PlotWidget::createLabelForAxis(Axis* axis)
{  
    // labelSize is QSize, labelFont.font is "Courier", labelFont.metrics is QFontMetrics for labelFont.font, axis->label is QString, colors.text is Qt::black
    if(axis != nullptr) {
        axis->labelSize.setHeight(labelFont.metrics.height());
        axis->labelSize.setWidth(labelFont.metrics.boundingRect(axis->label).width());
        axis->labelPix = QPixmap{axis->labelSize};
        axis->labelPix.fill(QColor{255, 0, 0, 50});
	QPainter painter(&axis->labelPix);
	painter.setPen(QPen{colors.text});
	painter.setFont(labelFont.font);
	painter.drawText(0, 0, axis->labelSize.width(), axis->labelSize.height(), Qt::AlignCenter, axis->label);
	painter.drawRect(labelFont.metrics.boundingRect(axis->label));
	qDebug() << axis->label << labelFont.metrics.boundingRect(axis->label);
    }
}

When it is run it draws:

and outputs: "Time [s]" QRect(0,-14 75x18)

Why is it giving me -14 as the y position of the bounding rect? Also, the left side T in the drawn label is truncated, why is that? Since I am making the labelPix the width of the boundingRect of label string and using Qt::AlignCenter the entire text should fit inside the labelPix.

[Pl45m4]

@CJha

It seems, that you are painting on PlotWidget using QPainter outside of its paintEvent. This can lead to unwanted bahavior and shouldn't be done.

In your case, your text won't update() (is redrawn) together with the rest of the widget, for example, when resizing.

[CJha]

@Pl45m4 In this function I am painting on axis->labelPix which is a QPixmap. The axis->labelPix is then put in its correct position using QPainter in the paintEvent() of PlotWidget.