Ruler: Moved calculate_tick_spacing into View

[pulseview.git] / pv / view / view.cpp

diff --git a/pv/view/view.cpp b/pv/view/view.cpp
index c96063536c0e917bc86336bbf2d7cb071a63b3c6..fce5b18c2fc487b52a3cb365b47e2d4a9f76c65c 100644 (file)
--- a/pv/view/view.cpp
+++ b/pv/view/view.cpp
@@ -22,13 +22,17 @@
 #include <libsigrokdecode/libsigrokdecode.h>
 #endif
 
+#include <extdef.h>
+
 #include <cassert>
 #include <climits>
 #include <cmath>
 #include <mutex>
 #include <unordered_set>
 
+#include <QApplication>
 #include <QEvent>
+#include <QFontMetrics>
 #include <QMouseEvent>
 #include <QScrollBar>
 
@@ -44,13 +48,17 @@
 #include "view.hpp"
 #include "viewport.hpp"
 
-#include "pv/sigsession.hpp"
+#include "pv/session.hpp"
 #include "pv/data/logic.hpp"
 #include "pv/data/logicsnapshot.hpp"
+#include "pv/util.hpp"
 
 using boost::shared_lock;
 using boost::shared_mutex;
+
 using pv::data::SignalData;
+using pv::util::format_time;
+
 using std::back_inserter;
 using std::deque;
 using std::dynamic_pointer_cast;
@@ -75,6 +83,8 @@ const double View::MinScale = 1e-15;
 
 const int View::MaxScrollValue = INT_MAX / 2;
 
+const int View::ScaleUnits[3] = {1, 2, 5};
+
 const QColor View::CursorAreaColour(220, 231, 243);
 
 const QSizeF View::LabelPadding(4, 0);
@@ -90,6 +100,8 @@ View::View(Session &session, QWidget *parent) :
        offset_(0),
        v_offset_(0),
        updating_scroll_(false),
+       tick_period_(0.0),
+       tick_prefix_(0),
        show_cursors_(false),
        cursors_(*this),
        hover_point_(-1, -1)
@@ -147,6 +159,9 @@ View::View(Session &session, QWidget *parent) :
        // make sure the transparent widgets are on the top
        cursorheader_->raise();
        header_->raise();
+
+       // Update the zoom state
+       calculate_tick_spacing();
 }
 
 Session& View::session()
@@ -199,6 +214,16 @@ unsigned int View::depth() const
        return 0;
 }
 
+unsigned int View::tick_prefix() const
+{
+       return tick_prefix_;
+}
+
+double View::tick_period() const
+{
+       return tick_period_;
+}
+
 void View::zoom(double steps)
 {
        zoom(steps, viewport_->width() / 2);
@@ -256,6 +281,8 @@ void View::set_scale_offset(double scale, double offset)
        scale_ = scale;
        offset_ = offset;
 
+       calculate_tick_spacing();
+
        update_scroll();
        ruler_->update();
        cursorheader_->update();
@@ -379,6 +406,40 @@ void View::set_zoom(double scale, int offset)
        set_scale_offset(new_scale, new_offset);
 }
 
+void View::calculate_tick_spacing()
+{
+       const double SpacingIncrement = 32.0f;
+       const double MinValueSpacing = 32.0f;
+
+       double min_width = SpacingIncrement, typical_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;
+
+               typical_width = m.boundingRect(0, 0, INT_MAX, INT_MAX,
+                       Qt::AlignLeft | Qt::AlignTop,
+                       format_time(offset_, tick_prefix_)).width() +
+                               MinValueSpacing;
+
+               min_width += SpacingIncrement;
+
+       } while(typical_width > tick_period_ / scale_);
+}
+
 void View::update_scroll()
 {
        assert(viewport_);