bmsapp: comparison src/RangedSlider.cpp

-:053c0578cf58
+:d11a3e713e3b
 _prefRangePen(Qt::NoPen),
 _markerBrush(QColor(255,255,255)),
 _markerTextIsValue(false),
 indicatorTextFont("Arial", 10, QFont::Normal) // Previously we just did the indicator text in 'default' font
 {
-// Ensure this->heightInPixels is properly initialised
+// Fixed minimum size.
-//    this->recalculateHeightInPixels();
+this->setMinimumSize(60, 20);
+this->setSizePolicy( QSizePolicy::MinimumExpanding, QSizePolicy::Fixed );
-// In principle we want to set our min/max sizes etc here.  However, if, say, a maximumSize property has been set
-// for this object in a Designer UI File (eg ui/mainWindow.ui) then that setting will override this one, because it
+// There no particular reason to limit our horizontal size, so, in principle, this call asks that there be no such
-// will be applied later (in fact pretty much straight after this constructor returns).  So we also make this call
+// (practical) limit.
-// inside setValue(), which will be invoked _after_ the setter calls that were auto-generated from the Designer UI
+this->setMaximumWidth(QWIDGETSIZE_MAX);
-// File.
-this->setSizes();
+// Generate mouse move events whenever mouse movers over widget.
+this->setMouseTracking(true);
-// Generate mouse move events whenever mouse movers over widget.
-this->setMouseTracking(true);
+this->repaint();
+}
-this->repaint();
-}
 /**
 * @brief Set the normal limits in the _prexXxx values and calculate
 *        the real drawing limits so that we can see if a value is slightly
 *        out of range.
 	_markerText = QString("%1").arg(value, 0, 'f', _prec);
 	qDebug() << _markerText;
 }
 update();
-// See comment in constructor for why we call this here
-//this->setSizes();
 return;
 }
 void RangedSlider::setPrecision(int precision)
 {
 _markerTextIsValue = val;
 update();
 }
-void RangedSlider::recalculateHeightInPixels() const {
-//
-// We need to be able to tell Qt about our minimum and preferred size in pixels.  This is something that's going
-// to depend on the dots-per-inch (DPI) resolution of the monitor we're being displayed on.  Advice at
-// https://doc.qt.io/qt-5/highdpi.html is that, for best High DPI display support, we should replace hard-coded
-// sizes in layouts and drawing code with values calculated from font metrics or screen size.  For this widget, we
-// use font sizes (as described in more detail later in this comment) as it seems simpler and the height of the
-// widget really is determined by the size of the text it contains.
-//
-// In theory, someone might be running the app on a system with multiple screens with different DPI resolutions,
-// so, in principle we ought to do redo size calculations every time the widget is moved, in case it moves from one
-// screen to another and the resolution changes.  In practice, I'm not sure how big a requirement this is.  So, for
-// now, have just tried to organise things so that it would, in principle, be possible to implement such behaviour
-// in future.
-//
-// We want height to be fixed, as the slider does not get more readable if you make it taller.  So minimum and
-// preferred height are the same.
-//
-// For width, We are OK for them to expand and contract horizontally, within reason, as the size of the main window
-// changes.  Minimum and preferred widths are a bit of a rule-of-thumb, but 2× and 4× height are a sensible stab.
-//
-// Firstly we have to determine what the fixed height is.  We could query the DPI resolution and size of the current
-// screen, but the simplest thing is to use font sizes.  The slider is basically two lines of characters high.  Top
-// line is the "indicator" text that sits above the slider visual in the middle of the "preferred range".  Bottom
-// line is the slider visual and the "value" text that sits to the right of the slider visual.  The fonts for both
-// bits of text are set in device-independent points in the constructor, and we can just query their height etc in
-// pixels.
-//
-// Secondly, the way we tell Qt about minimum and preferred sizes is slightly different:
-//  • setMinimumSize() tells Qt not to make us smaller than the specified size when resizing windows etc, HOWEVER
-//    it does not determine what size we are initially drawn
-//  • instead, Qt calls sizeHint() when doing initial layout, and we must override this to supply our desired
-//    initial dimensions.  NB: Although it makes no sense, there is nothing to stop this method returning dimensions
-//    below the minimums already set via setMinimumSize().  (AIUI, sizeHint() is also called on resize events to
-//    find our preferred dimensions.)
-//
-// The final wrinkle is that the height of the font sort of depends what you mean.  Strictly, using the inter-line
-// spacing (= height plus leading, though the latter is often 0) gives you enough space to show any character of the
-// font.  It is helpful for the indicator text to have a bit of space below it before we draw the graphical bit, and
-// it's not a large font in any case.  However, for large value text font we don't necessarily need all this space
-// because we currently only show digits and decimal points, which don't require space below the baseline.  However,
-// assumptions about space below the baseline are locale-specific, so, say, using ascent() instead of lineSpacing()
-// could end up painting us into a corner.
-//
-//QFontMetrics indicatorTextFontMetrics(this->indicatorTextFont);
-//   this->heightInPixels = this->height();
-return;
-}
-void RangedSlider::setSizes() {
-// Fixed minimum size.
-this->setMinimumSize(60, 20);
-this->setSizePolicy( QSizePolicy::MinimumExpanding, QSizePolicy::Fixed );
-// There no particular reason to limit our horizontal size, so, in principle, this call asks that there be no such
-// (practical) limit.
-this->setMaximumWidth(QWIDGETSIZE_MAX);
-return;
-}
-//QSize RangedSlider::sizeHint() const
-//{
-//   this->recalculateHeightInPixels();
-//   return QSize(4 * this->heightInPixels, this->heightInPixels);
-//}
 void RangedSlider::mouseMoveEvent(QMouseEvent* event)
 {
 event->accept();
 return;
 }
-void RangedSlider::moveEvent(QMoveEvent *event) {
+void RangedSlider::moveEvent(QMoveEvent *event)
-// If we've moved, we might be on a new screen with a different DPI resolution...
+{
-// .:TBD:. This almost certainly needs further work and further testing.  It's far from clear whether our font size
+QWidget::moveEvent(event);
-//         querying will give different answers just because the app has been moved from one screen to another.
+return;
-this->recalculateHeightInPixels();
+}
-QWidget::moveEvent(event);
-return;
-}

Mercurial > bmsapp / file comparison

comparison: src/RangedSlider.cpp

src/RangedSlider.cpp