yLeft axis constant width

I made an array (vertically ) of qwtplot that xBottom axis are synchronized ( just like the plot matrix). Now my problem is that yLeft axis values are changing , so the number of digits will shrink and expand in effect this will misallign my xBottom axis.

My idea of a solution would be to have a constant width on QwtScaleWidget by setting minimumWidth() to something like the width of 6 digits numbers. but this is kinda hacky. Is there an elegant solution to my woes uwe?

By the way i tried setting QwtScaleWidget's minimumWidth and found that the canvas won't respect QwtScaleWidget.

scalewidget was overdrawn by the canvas

baray98

More debugging showed me that by adjusting scaleDraw to the max width of all yLeft axis will do the trick.. but changes ( or redraw) is not visible until I will resize the widget. I have tried both replot and repaint on each plot and nothing happens.

Uwe how will i trigger a redraw after changing scaleDraw's minimumExtent ?

baray98

What about QwtPlot::updateLayout() ?

You can call updateLayout() manually, but it is also called internally for each LayoutRequest event. AFAIR this event is posted by QWidget::updateGeometry(), so I guess you could also do plot->updateGeometry(). Using LayoutRequest events might be preferable as several LayoutRequest can be collected by Qt to a single one.

Uwe

updateLayout will do the trick but not updateGeometry();

solved

baray98

I am working on the same problem. Why doesn't the canvas respect the axis widget's minimumWidth()? Is this a bug?

Also, QwtPlot::updateLayout is not a slot, so I can't just do:

Code:

---

connect(m_ui->qwtPlot->axisWidget(QwtPlot::yLeft), SIGNAL(scaleDivChanged()),
			m_ui->qwtPlot, SLOT(updateLayout()));

---

to work around this.

---

Added after 1 6 minutes:

This seems to do the trick:

Code:

---

m_ui->qwtPlot->axisWidget(QwtPlot::xBottom)->setMinBorderDist(90, 20);
m_ui->qwtPlot->plotLayout()->setAlignCanvasToScales(true);

---

This has some side effects I don't really like (the canvas doesn't stretch to the edge on the top and right) but it helps with a lot of the flickering when axis labels change.