void Ruler::paintEvent(QPaintEvent*)
{
- const double SpacingIncrement = 32.0f;
- const double MinValueSpacing = 32.0f;
const int ValueMargin = 3;
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);
- double min_width = SpacingIncrement, typical_width;
- double tick_period;
- unsigned int prefix;
-
- // Find tick spacing, and number formatting that does not cause
- // value to collide.
- do
- {
- const double min_period = _view.scale() * min_width;
-
- const int order = (int)floorf(log10f(min_period));
- const double order_decimal = pow(10.0, order);
-
- unsigned int unit = 0;
-
- do
- {
- tick_period = order_decimal * ScaleUnits[unit++];
- } while (tick_period < min_period && unit < countof(ScaleUnits));
-
- prefix = (order - pv::util::FirstSIPrefixPower) / 3;
+ std::pair<double, unsigned int> spacing =
+ calculate_tick_spacing(p, _view.scale(), _view.offset());
- typical_width = p.boundingRect(0, 0, INT_MAX, INT_MAX,
- AlignLeft | AlignTop, pv::util::format_time(_view.offset(),
- prefix)).width() + MinValueSpacing;
-
- min_width += SpacingIncrement;
-
- } while(typical_width > tick_period / _view.scale());
+ double tick_period = spacing.first;
+ unsigned int prefix = spacing.second;
const int text_height = p.boundingRect(0, 0, INT_MAX, INT_MAX,
AlignLeft | AlignTop, "8").height();
update();
}
+std::pair<double, unsigned int> Ruler::calculate_tick_spacing(
+ QPainter& p, double scale, double offset)
+{
+ const double SpacingIncrement = 32.0f;
+ const double MinValueSpacing = 32.0f;
+
+ double min_width = SpacingIncrement, typical_width;
+
+ double tick_period;
+ unsigned int prefix;
+
+ do {
+ const double min_period = scale * min_width;
+
+ const int order = (int)floorf(log10f(min_period));
+ const double order_decimal = pow(10.0, order);
+
+ unsigned int unit = 0;
+
+ do {
+ tick_period = order_decimal * ScaleUnits[unit++];
+ } while (tick_period < min_period && unit < countof(ScaleUnits));
+
+ prefix = (order - pv::util::FirstSIPrefixPower) / 3;
+
+ typical_width = p.boundingRect(0, 0, INT_MAX, INT_MAX,
+ AlignLeft | AlignTop, pv::util::format_time(offset,
+ prefix)).width() + MinValueSpacing;
+
+ min_width += SpacingIncrement;
+
+ } while(typical_width > tick_period / scale);
+
+ return std::make_pair(tick_period, prefix);
+}
+
} // namespace view
} // namespace pv
public:
Ruler(View &parent);
+ /**
+ * Find a tick spacing and number formatting that does not cause
+ * the values to collide.
+ * @param p A QPainter used to determine the needed space for the values.
+ * @param scale A pv::view::View's scale.
+ * @param offset A pv::view::View's offset.
+ *
+ * @return The tick period to use in 'first' and the prefix in 'second'.
+ */
+ static std::pair<double, unsigned int> calculate_tick_spacing(
+ QPainter& p, double scale, double offset);
+
public:
QSize sizeHint() const;