X-Git-Url: http://sigrok.org/gitweb/?a=blobdiff_plain;f=pv%2Fview%2Fview.cpp;h=fdb9354b9315cefe4c4a06d23b00a879db7bab82;hb=818f617924d2ed393cadd362fdafbd9d4288848f;hp=032546dba034eda4cea63cc3f60489127cd28d9d;hpb=d40f4db76fc8120fcd54ace8c6fce63387e025ca;p=pulseview.git

diff --git a/pv/view/view.cpp b/pv/view/view.cpp
index 032546db..fdb9354b 100644
--- a/pv/view/view.cpp
+++ b/pv/view/view.cpp
@@ -84,7 +84,7 @@ namespace pv {
 namespace view {
 
 const double View::MaxScale = 1e9;
-const double View::MinScale = 1e-15;
+const double View::MinScale = 1e-12;
 
 const int View::MaxScrollValue = INT_MAX / 2;
 const int View::MaxViewAutoUpdateRate = 25; // No more than 25 Hz with sticky scrolling
@@ -493,8 +493,13 @@ void View::set_zoom(double scale, int offset)
 
 void View::calculate_tick_spacing()
 {
-	const double SpacingIncrement = 32.0f;
-	const double MinValueSpacing = 32.0f;
+	const double SpacingIncrement = 10.0f;
+	const double MinValueSpacing = 25.0f;
+
+	// Figure out the highest numeric value visible on a label
+	const QSize areaSize = viewport_->size();
+	const double max_time = max(fabs(offset_),
+		fabs(offset_ + scale_ * areaSize.width()));
 
 	double min_width = SpacingIncrement;
 	double label_width, tick_period_width;
@@ -507,13 +512,19 @@ void View::calculate_tick_spacing()
 		const int order = (int)floorf(log10f(min_period));
 		const double order_decimal = pow(10.0, order);
 
+		// Allow for a margin of error so that a scale unit of 1 can be used.
+		// Otherwise, for a SU of 1 the tick period will almost always be below
+		// the min_period by a small amount - and thus skipped in favor of 2.
+		// Note: margin assumes that SU[0] and SU[1] contain the smallest values
+		double tp_margin = (ScaleUnits[0] + ScaleUnits[1]) / 2.0;
+		double tp_with_margin;
 		unsigned int unit = 0;
 
 		do {
-			tick_period_ = order_decimal * ScaleUnits[unit++];
-		} while (tick_period_ < min_period &&
-			unit < countof(ScaleUnits));
+			tp_with_margin = order_decimal * (ScaleUnits[unit++] + tp_margin);
+		} while (tp_with_margin < min_period && unit < countof(ScaleUnits));
 
+		tick_period_ = order_decimal * ScaleUnits[unit - 1];
 		tick_prefix_ = (order - pv::util::FirstSIPrefixPower) / 3;
 
 		// Precision is the number of fractional digits required, not
@@ -523,7 +534,7 @@ void View::calculate_tick_spacing()
 		tick_period_width = tick_period_ / scale_;
 
 		const QString label_text =
-			format_time(offset_, tick_prefix_, time_unit_, tick_precision_);
+			format_time(max_time, tick_prefix_, time_unit_, tick_precision_);
 
 		label_width = m.boundingRect(0, 0, INT_MAX, INT_MAX,
 			Qt::AlignLeft | Qt::AlignTop, label_text).width() +