+void View::calculate_tick_spacing()
+{
+ const double SpacingIncrement = 32.0f;
+ const double MinValueSpacing = 32.0f;
+
+ double min_width = SpacingIncrement;
+ double label_width, tick_period_width;
+
+ QFontMetrics m(QApplication::font());
+
+ 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));
+
+ tick_prefix_ = (order - pv::util::FirstSIPrefixPower) / 3;
+
+ // Precision is the number of fractional digits required, not
+ // taking the prefix into account (and it must never be negative)
+ tick_precision_ = std::max((int)ceil(log10f(1 / tick_period_)), 0);
+
+ tick_period_width = tick_period_ / scale_;
+
+ const QString label_text =
+ format_time(offset_, tick_prefix_, time_unit_, tick_precision_);
+
+ label_width = m.boundingRect(0, 0, INT_MAX, INT_MAX,
+ Qt::AlignLeft | Qt::AlignTop, label_text).width() +
+ MinValueSpacing;
+
+ min_width += SpacingIncrement;
+
+ } while (tick_period_width < label_width);
+}
+