Don't use deprecated headers.

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

/*
 * This file is part of the PulseView project.
 *
 * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#ifdef ENABLE_DECODE
#include <libsigrokdecode/libsigrokdecode.h>
#endif

#include <extdef.h>

#include <algorithm>
#include <cassert>
#include <climits>
#include <cmath>
#include <iostream>
#include <iterator>
#include <mutex>
#include <unordered_set>

#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/serialization/serialization.hpp>
#include <boost/thread/locks.hpp>

#include <QApplication>
#include <QHBoxLayout>
#include <QEvent>
#include <QFontMetrics>
#include <QMouseEvent>
#include <QScrollBar>

#include <libsigrokcxx/libsigrokcxx.hpp>

#include "analogsignal.hpp"
#include "header.hpp"
#include "logicsignal.hpp"
#include "ruler.hpp"
#include "signal.hpp"
#include "tracegroup.hpp"
#include "triggermarker.hpp"
#include "view.hpp"
#include "viewport.hpp"

#include "pv/session.hpp"
#include "pv/globalsettings.hpp"
#include "pv/devices/device.hpp"
#include "pv/data/logic.hpp"
#include "pv/data/logicsegment.hpp"
#include "pv/util.hpp"

#ifdef ENABLE_DECODE
#include "decodetrace.hpp"
#endif

using boost::shared_lock;
using boost::shared_mutex;

using pv::data::SignalData;
using pv::data::Segment;
using pv::util::TimeUnit;
using pv::util::Timestamp;

using std::back_inserter;
using std::copy_if;
using std::deque;
using std::dynamic_pointer_cast;
using std::inserter;
using std::list;
using std::lock_guard;
using std::max;
using std::make_pair;
using std::make_shared;
using std::min;
using std::pair;
using std::set;
using std::set_difference;
using std::shared_ptr;
using std::unordered_map;
using std::unordered_set;
using std::vector;
using std::weak_ptr;

namespace pv {
namespace views {
namespace TraceView {

const Timestamp View::MaxScale("1e9");
const Timestamp View::MinScale("1e-12");

const int View::MaxScrollValue = INT_MAX / 2;
const int View::MaxViewAutoUpdateRate = 25; // No more than 25 Hz with sticky scrolling

const int View::ScaleUnits[3] = {1, 2, 5};


CustomAbstractScrollArea::CustomAbstractScrollArea(QWidget *parent) :
        QAbstractScrollArea(parent)
{
}

void CustomAbstractScrollArea::setViewportMargins(int left, int top, int right, int bottom)
{
        QAbstractScrollArea::setViewportMargins(left, top, right, bottom);
}

bool CustomAbstractScrollArea::viewportEvent(QEvent *event)
{
        switch (event->type()) {
        case QEvent::Paint:
        case QEvent::MouseButtonPress:
        case QEvent::MouseButtonRelease:
        case QEvent::MouseButtonDblClick:
        case QEvent::MouseMove:
        case QEvent::Wheel:
        case QEvent::TouchBegin:
        case QEvent::TouchUpdate:
        case QEvent::TouchEnd:
                return false;
        default:
                return QAbstractScrollArea::viewportEvent(event);
        }
}

View::View(Session &session, bool is_main_view, QWidget *parent) :
        ViewBase(session, is_main_view, parent),
        viewport_(new Viewport(*this)),
        ruler_(new Ruler(*this)),
        header_(new Header(*this)),
        scrollarea_(this),
        scale_(1e-3),
        offset_(0),
        updating_scroll_(false),
        sticky_scrolling_(false), // Default setting is set in MainWindow::setup_ui()
        always_zoom_to_fit_(false),
        tick_period_(0),
        tick_prefix_(pv::util::SIPrefix::yocto),
        tick_precision_(0),
        time_unit_(util::TimeUnit::Time),
        show_cursors_(false),
        cursors_(new CursorPair(*this)),
        next_flag_text_('A'),
        trigger_markers_(),
        hover_point_(-1, -1),
        scroll_needs_defaults_(false),
        saved_v_offset_(0),
        size_finalized_(false)
{
        GlobalSettings settings;
        coloured_bg_ = settings.value(GlobalSettings::Key_View_ColouredBG).toBool();

        connect(scrollarea_.horizontalScrollBar(), SIGNAL(valueChanged(int)),
                this, SLOT(h_scroll_value_changed(int)));
        connect(scrollarea_.verticalScrollBar(), SIGNAL(valueChanged(int)),
                this, SLOT(v_scroll_value_changed()));

        connect(header_, SIGNAL(selection_changed()),
                ruler_, SLOT(clear_selection()));
        connect(ruler_, SIGNAL(selection_changed()),
                header_, SLOT(clear_selection()));

        connect(header_, SIGNAL(selection_changed()),
                this, SIGNAL(selection_changed()));
        connect(ruler_, SIGNAL(selection_changed()),
                this, SIGNAL(selection_changed()));

        connect(this, SIGNAL(hover_point_changed()),
                this, SLOT(on_hover_point_changed()));

        connect(&lazy_event_handler_, SIGNAL(timeout()),
                this, SLOT(process_sticky_events()));
        lazy_event_handler_.setSingleShot(true);

        connect(&delayed_view_updater_, SIGNAL(timeout()),
                this, SLOT(perform_delayed_view_update()));
        delayed_view_updater_.setSingleShot(true);
        delayed_view_updater_.setInterval(1000 / MaxViewAutoUpdateRate);

        /* To let the scroll area fill up the parent QWidget (this), we need a layout */
        QHBoxLayout *layout = new QHBoxLayout(this);
        setLayout(layout);
        layout->setContentsMargins(0, 0, 0, 0);
        layout->addWidget(&scrollarea_);

        scrollarea_.setViewport(viewport_);

        viewport_->installEventFilter(this);
        ruler_->installEventFilter(this);
        header_->installEventFilter(this);

        // Trigger the initial event manually. The default device has signals
        // which were created before this object came into being
        signals_changed();

        // make sure the transparent widgets are on the top
        ruler_->raise();
        header_->raise();

        // Update the zoom state
        calculate_tick_spacing();
}

Session& View::session()
{
        return session_;
}

const Session& View::session() const
{
        return session_;
}

std::unordered_set< std::shared_ptr<Signal> > View::signals() const
{
        return signals_;
}

void View::clear_signals()
{
        signals_.clear();
}

void View::add_signal(const shared_ptr<Signal> signal)
{
        signals_.insert(signal);
}

#ifdef ENABLE_DECODE
void View::clear_decode_signals()
{
        decode_traces_.clear();
}

void View::add_decode_signal(shared_ptr<data::SignalBase> signalbase)
{
        shared_ptr<DecodeTrace> d(
                new DecodeTrace(session_, signalbase, decode_traces_.size()));
        decode_traces_.push_back(d);
}

void View::remove_decode_signal(shared_ptr<data::SignalBase> signalbase)
{
        for (auto i = decode_traces_.begin(); i != decode_traces_.end(); i++)
                if ((*i)->base() == signalbase) {
                        decode_traces_.erase(i);
                        signals_changed();
                        return;
                }
}
#endif

View* View::view()
{
        return this;
}

const View* View::view() const
{
        return this;
}

Viewport* View::viewport()
{
        return viewport_;
}

const Viewport* View::viewport() const
{
        return viewport_;
}

void View::save_settings(QSettings &settings) const
{
        settings.setValue("scale", scale_);
        settings.setValue("v_offset",
                scrollarea_.verticalScrollBar()->sliderPosition());

        std::stringstream ss;
        boost::archive::text_oarchive oa(ss);
        oa << boost::serialization::make_nvp("offset", offset_);
        settings.setValue("offset", QString::fromStdString(ss.str()));

        for (shared_ptr<Signal> signal : signals_) {
                settings.beginGroup(signal->base()->internal_name());
                signal->save_settings(settings);
                settings.endGroup();
        }
}

void View::restore_settings(QSettings &settings)
{
        // Note: It is assumed that this function is only called once,
        // immediately after restoring a previous session.

        if (settings.contains("scale"))
                set_scale(settings.value("scale").toDouble());

        if (settings.contains("offset")) {
                util::Timestamp offset;
                std::stringstream ss;
                ss << settings.value("offset").toString().toStdString();

                boost::archive::text_iarchive ia(ss);
                ia >> boost::serialization::make_nvp("offset", offset);

                set_offset(offset);
        }

        for (shared_ptr<Signal> signal : signals_) {
                settings.beginGroup(signal->base()->internal_name());
                signal->restore_settings(settings);
                settings.endGroup();
        }

        if (settings.contains("v_offset")) {
                saved_v_offset_ = settings.value("v_offset").toInt();
                set_v_offset(saved_v_offset_);
                scroll_needs_defaults_ = false;
                // Note: see resizeEvent() for additional information
        }
}

vector< shared_ptr<TimeItem> > View::time_items() const
{
        const vector<shared_ptr<Flag>> f(flags());
        vector<shared_ptr<TimeItem>> items(f.begin(), f.end());
        items.push_back(cursors_);
        items.push_back(cursors_->first());
        items.push_back(cursors_->second());

        for (auto trigger_marker : trigger_markers_)
                items.push_back(trigger_marker);

        return items;
}

double View::scale() const
{
        return scale_;
}

void View::set_scale(double scale)
{
        if (scale_ != scale) {
                scale_ = scale;
                Q_EMIT scale_changed();
        }
}

const Timestamp& View::offset() const
{
        return offset_;
}

void View::set_offset(const pv::util::Timestamp& offset)
{
        if (offset_ != offset) {
                offset_ = offset;
                Q_EMIT offset_changed();
        }
}

int View::owner_visual_v_offset() const
{
        return -scrollarea_.verticalScrollBar()->sliderPosition();
}

void View::set_v_offset(int offset)
{
        scrollarea_.verticalScrollBar()->setSliderPosition(offset);
        header_->update();
        viewport_->update();
}

unsigned int View::depth() const
{
        return 0;
}

pv::util::SIPrefix View::tick_prefix() const
{
        return tick_prefix_;
}

void View::set_tick_prefix(pv::util::SIPrefix tick_prefix)
{
        if (tick_prefix_ != tick_prefix) {
                tick_prefix_ = tick_prefix;
                Q_EMIT tick_prefix_changed();
        }
}

unsigned int View::tick_precision() const
{
        return tick_precision_;
}

void View::set_tick_precision(unsigned tick_precision)
{
        if (tick_precision_ != tick_precision) {
                tick_precision_ = tick_precision;
                Q_EMIT tick_precision_changed();
        }
}

const pv::util::Timestamp& View::tick_period() const
{
        return tick_period_;
}

void View::set_tick_period(const pv::util::Timestamp& tick_period)
{
        if (tick_period_ != tick_period) {
                tick_period_ = tick_period;
                Q_EMIT tick_period_changed();
        }
}

TimeUnit View::time_unit() const
{
        return time_unit_;
}

void View::set_time_unit(pv::util::TimeUnit time_unit)
{
        if (time_unit_ != time_unit) {
                time_unit_ = time_unit;
                Q_EMIT time_unit_changed();
        }
}

void View::zoom(double steps)
{
        zoom(steps, viewport_->width() / 2);
}

void View::zoom(double steps, int offset)
{
        set_zoom(scale_ * pow(3.0/2.0, -steps), offset);
}

void View::zoom_fit(bool gui_state)
{
        // Act as one-shot when stopped, toggle along with the GUI otherwise
        if (session_.get_capture_state() == Session::Stopped) {
                always_zoom_to_fit_ = false;
                always_zoom_to_fit_changed(false);
        } else {
                always_zoom_to_fit_ = gui_state;
                always_zoom_to_fit_changed(gui_state);
        }

        const pair<Timestamp, Timestamp> extents = get_time_extents();
        const Timestamp delta = extents.second - extents.first;
        if (delta < Timestamp("1e-12"))
                return;

        assert(viewport_);
        const int w = viewport_->width();
        if (w <= 0)
                return;

        const Timestamp scale = max(min(delta / w, MaxScale), MinScale);
        set_scale_offset(scale.convert_to<double>(), extents.first);
}

void View::zoom_one_to_one()
{
        using pv::data::SignalData;

        // Make a set of all the visible data objects
        set< shared_ptr<SignalData> > visible_data = get_visible_data();
        if (visible_data.empty())
                return;

        assert(viewport_);
        const int w = viewport_->width();
        if (w <= 0)
                return;

        set_zoom(1.0 / session_.get_samplerate(), w / 2);
}

void View::set_scale_offset(double scale, const Timestamp& offset)
{
        // Disable sticky scrolling / always zoom to fit when acquisition runs
        // and user drags the viewport
        if ((scale_ == scale) && (offset_ != offset) &&
                        (session_.get_capture_state() == Session::Running)) {

                if (sticky_scrolling_) {
                        sticky_scrolling_ = false;
                        sticky_scrolling_changed(false);
                }

                if (always_zoom_to_fit_) {
                        always_zoom_to_fit_ = false;
                        always_zoom_to_fit_changed(false);
                }
        }

        set_scale(scale);
        set_offset(offset);

        calculate_tick_spacing();

        update_scroll();
        ruler_->update();
        viewport_->update();
}

set< shared_ptr<SignalData> > View::get_visible_data() const
{
        // Make a set of all the visible data objects
        set< shared_ptr<SignalData> > visible_data;
        for (const shared_ptr<Signal> sig : signals_)
                if (sig->enabled())
                        visible_data.insert(sig->data());

        return visible_data;
}

pair<Timestamp, Timestamp> View::get_time_extents() const
{
        boost::optional<Timestamp> left_time, right_time;
        const set< shared_ptr<SignalData> > visible_data = get_visible_data();
        for (const shared_ptr<SignalData> d : visible_data) {
                const vector< shared_ptr<Segment> > segments =
                        d->segments();
                for (const shared_ptr<Segment> &s : segments) {
                        double samplerate = s->samplerate();
                        samplerate = (samplerate <= 0.0) ? 1.0 : samplerate;

                        const Timestamp start_time = s->start_time();
                        left_time = left_time ?
                                min(*left_time, start_time) :
                                                start_time;
                        right_time = right_time ?
                                max(*right_time, start_time + d->max_sample_count() / samplerate) :
                                                 start_time + d->max_sample_count() / samplerate;
                }
        }

        if (!left_time || !right_time)
                return make_pair(0, 0);

        assert(*left_time < *right_time);
        return make_pair(*left_time, *right_time);
}

void View::enable_sticky_scrolling(bool state)
{
        sticky_scrolling_ = state;
}

void View::toggle_sticky_scrolling(void)
{
        sticky_scrolling_ = !sticky_scrolling_;
}

void View::enable_coloured_bg(bool state)
{
        const vector<shared_ptr<TraceTreeItem>> items(
                list_by_type<TraceTreeItem>());

        for (shared_ptr<TraceTreeItem> i : items) {
                // Can't cast to Trace because it's abstract, so we need to
                // check for any derived classes individually

                shared_ptr<AnalogSignal> a = dynamic_pointer_cast<AnalogSignal>(i);
                if (a)
                        a->set_coloured_bg(state);

                shared_ptr<LogicSignal> l = dynamic_pointer_cast<LogicSignal>(i);
                if (l)
                        l->set_coloured_bg(state);

#ifdef ENABLE_DECODE
                shared_ptr<DecodeTrace> d = dynamic_pointer_cast<DecodeTrace>(i);
                if (d)
                        d->set_coloured_bg(state);
#endif
        }

        viewport_->update();
}

bool View::cursors_shown() const
{
        return show_cursors_;
}

void View::show_cursors(bool show)
{
        show_cursors_ = show;
        ruler_->update();
        viewport_->update();
}

void View::centre_cursors()
{
        const double time_width = scale_ * viewport_->width();
        cursors_->first()->set_time(offset_ + time_width * 0.4);
        cursors_->second()->set_time(offset_ + time_width * 0.6);
        ruler_->update();
        viewport_->update();
}

std::shared_ptr<CursorPair> View::cursors() const
{
        return cursors_;
}

void View::add_flag(const Timestamp& time)
{
        flags_.push_back(shared_ptr<Flag>(new Flag(*this, time,
                QString("%1").arg(next_flag_text_))));

        next_flag_text_ = (next_flag_text_ >= 'Z') ? 'A' :
                (next_flag_text_ + 1);

        time_item_appearance_changed(true, true);
}

void View::remove_flag(std::shared_ptr<Flag> flag)
{
        flags_.remove(flag);
        time_item_appearance_changed(true, true);
}

vector< std::shared_ptr<Flag> > View::flags() const
{
        vector< std::shared_ptr<Flag> > flags(flags_.begin(), flags_.end());
        stable_sort(flags.begin(), flags.end(),
                [](const shared_ptr<Flag> &a, const shared_ptr<Flag> &b) {
                        return a->time() < b->time();
                });

        return flags;
}

const QPoint& View::hover_point() const
{
        return hover_point_;
}

void View::restack_all_trace_tree_items()
{
        // Make a list of owners that is sorted from deepest first
        const vector<shared_ptr<TraceTreeItem>> items(
                list_by_type<TraceTreeItem>());
        set< TraceTreeItemOwner* > owners;
        for (const auto &r : items)
                owners.insert(r->owner());
        vector< TraceTreeItemOwner* > sorted_owners(owners.begin(), owners.end());
        sort(sorted_owners.begin(), sorted_owners.end(),
                [](const TraceTreeItemOwner* a, const TraceTreeItemOwner *b) {
                        return a->depth() > b->depth(); });

        // Restack the items recursively
        for (auto &o : sorted_owners)
                o->restack_items();

        // Re-assign background colors
        bool next_bgcolour_state = 0;

        for (auto &o : sorted_owners)
                next_bgcolour_state = o->reassign_bgcolour_states(next_bgcolour_state);

        // Animate the items to their destination
        for (const auto &i : items)
                i->animate_to_layout_v_offset();
}

void View::trigger_event(util::Timestamp location)
{
        trigger_markers_.push_back(shared_ptr<TriggerMarker>(
                new TriggerMarker(*this, location)));
}

void View::get_scroll_layout(double &length, Timestamp &offset) const
{
        const pair<Timestamp, Timestamp> extents = get_time_extents();
        length = ((extents.second - extents.first) / scale_).convert_to<double>();
        offset = offset_ / scale_;
}

void View::set_zoom(double scale, int offset)
{
        // Reset the "always zoom to fit" feature as the user changed the zoom
        always_zoom_to_fit_ = false;
        always_zoom_to_fit_changed(false);

        const Timestamp cursor_offset = offset_ + scale_ * offset;
        const Timestamp new_scale = max(min(Timestamp(scale), MaxScale), MinScale);
        const Timestamp new_offset = cursor_offset - new_scale * offset;
        set_scale_offset(new_scale.convert_to<double>(), new_offset);
}

void View::calculate_tick_spacing()
{
        const double SpacingIncrement = 10.0f;
        const double MinValueSpacing = 40.0f;

        // Figure out the highest numeric value visible on a label
        const QSize areaSize = viewport_->size();
        const Timestamp max_time = max(fabs(offset_),
                fabs(offset_ + scale_ * areaSize.width()));

        double min_width = SpacingIncrement;
        double label_width, tick_period_width;

        QFontMetrics m(QApplication::font());

        // Copies of the member variables with the same name, used in the calculation
        // and written back afterwards, so that we don't emit signals all the time
        // during the calculation.
        pv::util::Timestamp tick_period = tick_period_;
        pv::util::SIPrefix tick_prefix = tick_prefix_;
        unsigned tick_precision = tick_precision_;

        do {
                const double min_period = scale_ * min_width;

                const int order = (int)floorf(log10f(min_period));
                const pv::util::Timestamp order_decimal =
                        pow(pv::util::Timestamp(10), 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 {
                        tp_with_margin = order_decimal.convert_to<double>() *
                                (ScaleUnits[unit++] + tp_margin);
                } while (tp_with_margin < min_period && unit < countof(ScaleUnits));

                tick_period = order_decimal * ScaleUnits[unit - 1];
                tick_prefix = static_cast<pv::util::SIPrefix>(
                        (order - pv::util::exponent(pv::util::SIPrefix::yocto)) / 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(ceil(log10(1 / tick_period)).convert_to<int>(), 0);

                tick_period_width = (tick_period / scale_).convert_to<double>();

                const QString label_text = Ruler::format_time_with_distance(
                        tick_period, 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() +
                                MinValueSpacing;

                min_width += SpacingIncrement;
        } while (tick_period_width < label_width);

        set_tick_period(tick_period);
        set_tick_prefix(tick_prefix);
        set_tick_precision(tick_precision);
}

void View::update_scroll()
{
        assert(viewport_);
        QScrollBar *hscrollbar = scrollarea_.horizontalScrollBar();
        QScrollBar *vscrollbar = scrollarea_.verticalScrollBar();

        const QSize areaSize = viewport_->size();

        // Set the horizontal scroll bar
        double length = 0;
        Timestamp offset;
        get_scroll_layout(length, offset);
        length = max(length - areaSize.width(), 0.0);

        int major_tick_distance = (tick_period_ / scale_).convert_to<int>();

        hscrollbar->setPageStep(areaSize.width() / 2);
        hscrollbar->setSingleStep(major_tick_distance);

        updating_scroll_ = true;

        if (length < MaxScrollValue) {
                hscrollbar->setRange(0, length);
                hscrollbar->setSliderPosition(offset.convert_to<double>());
        } else {
                hscrollbar->setRange(0, MaxScrollValue);
                hscrollbar->setSliderPosition(
                        (offset_ * MaxScrollValue / (scale_ * length)).convert_to<double>());
        }

        updating_scroll_ = false;

        // Set the vertical scrollbar
        vscrollbar->setPageStep(areaSize.height());
        vscrollbar->setSingleStep(areaSize.height() / 8);

        const pair<int, int> extents = v_extents();

        // Don't change the scrollbar range if there are no traces
        if (extents.first != extents.second)
                vscrollbar->setRange(extents.first - areaSize.height(),
                        extents.second);

        if (scroll_needs_defaults_)
                set_scroll_default();
}

void View::reset_scroll()
{
        scrollarea_.verticalScrollBar()->setRange(0, 0);
}

void View::set_scroll_default()
{
        assert(viewport_);

        const QSize areaSize = viewport_->size();

        const pair<int, int> extents = v_extents();
        const int trace_height = extents.second - extents.first;

        // Do all traces fit in the view?
        if (areaSize.height() >= trace_height)
                // Center all traces vertically
                set_v_offset(extents.first -
                        ((areaSize.height() - trace_height) / 2));
        else
                // Put the first trace at the top, letting the bottom ones overflow
                set_v_offset(extents.first);

        // If we're not sure whether setting the defaults worked as
        // the window wasn't set up entirely yet, we want to be called
        // again later to make sure
        scroll_needs_defaults_ = !size_finalized_;
}

void View::update_layout()
{
        scrollarea_.setViewportMargins(
                header_->sizeHint().width() - Header::BaselineOffset,
                ruler_->sizeHint().height(), 0, 0);
        ruler_->setGeometry(viewport_->x(), 0,
                viewport_->width(), ruler_->extended_size_hint().height());
        header_->setGeometry(0, viewport_->y(),
                header_->extended_size_hint().width(), viewport_->height());
        update_scroll();
}

TraceTreeItemOwner* View::find_prevalent_trace_group(
        const shared_ptr<sigrok::ChannelGroup> &group,
        const unordered_map<shared_ptr<data::SignalBase>, shared_ptr<Signal> >
                &signal_map)
{
        assert(group);

        unordered_set<TraceTreeItemOwner*> owners;
        vector<TraceTreeItemOwner*> owner_list;

        // Make a set and a list of all the owners
        for (const auto &channel : group->channels()) {
                for (auto entry : signal_map) {
                        if (entry.first->channel() == channel) {
                                TraceTreeItemOwner *const o = (entry.second)->owner();
                                owner_list.push_back(o);
                                owners.insert(o);
                        }
                }
        }

        // Iterate through the list of owners, and find the most prevalent
        size_t max_prevalence = 0;
        TraceTreeItemOwner *prevalent_owner = nullptr;
        for (TraceTreeItemOwner *owner : owners) {
                const size_t prevalence = std::count_if(
                        owner_list.begin(), owner_list.end(),
                        [&](TraceTreeItemOwner *o) { return o == owner; });
                if (prevalence > max_prevalence) {
                        max_prevalence = prevalence;
                        prevalent_owner = owner;
                }
        }

        return prevalent_owner;
}

vector< shared_ptr<Trace> > View::extract_new_traces_for_channels(
        const vector< shared_ptr<sigrok::Channel> > &channels,
        const unordered_map<shared_ptr<data::SignalBase>, shared_ptr<Signal> >
                &signal_map,
        set< shared_ptr<Trace> > &add_list)
{
        vector< shared_ptr<Trace> > filtered_traces;

        for (const auto &channel : channels) {
                for (auto entry : signal_map) {
                        if (entry.first->channel() == channel) {
                                shared_ptr<Trace> trace = entry.second;
                                const auto list_iter = add_list.find(trace);
                                if (list_iter == add_list.end())
                                        continue;

                                filtered_traces.push_back(trace);
                                add_list.erase(list_iter);
                        }
                }
        }

        return filtered_traces;
}

void View::determine_time_unit()
{
        // Check whether we know the sample rate and hence can use time as the unit
        if (time_unit_ == util::TimeUnit::Samples) {
                // Check all signals but...
                for (const shared_ptr<Signal> signal : signals_) {
                        const shared_ptr<SignalData> data = signal->data();

                        // ...only check first segment of each
                        const vector< shared_ptr<Segment> > segments = data->segments();
                        if (!segments.empty())
                                if (segments[0]->samplerate()) {
                                        set_time_unit(util::TimeUnit::Time);
                                        break;
                                }
                }
        }
}

bool View::eventFilter(QObject *object, QEvent *event)
{
        const QEvent::Type type = event->type();
        if (type == QEvent::MouseMove) {

                const QMouseEvent *const mouse_event = (QMouseEvent*)event;
                if (object == viewport_)
                        hover_point_ = mouse_event->pos();
                else if (object == ruler_)
                        hover_point_ = QPoint(mouse_event->x(), 0);
                else if (object == header_)
                        hover_point_ = QPoint(0, mouse_event->y());
                else
                        hover_point_ = QPoint(-1, -1);

                hover_point_changed();

        } else if (type == QEvent::Leave) {
                hover_point_ = QPoint(-1, -1);
                hover_point_changed();
        }

        return QObject::eventFilter(object, event);
}

void View::resizeEvent(QResizeEvent*)
{
        update_layout();

        // This is somewhat of a hack, unfortunately. We cannot use
        // set_v_offset() from within restore_settings() as the view
        // at that point is neither visible nor properly sized.
        // This is the least intrusive workaround I could come up
        // with: set the vertical offset (or scroll defaults) when
        // the view is visible and resized to its final size.
        // Resize events that are sent when the view is not visible
        // must be ignored as they have wrong sizes, potentially
        // preventing the v offset from being set successfully.

        if (isVisible())
                size_finalized_ = true;

        if (size_finalized_ && saved_v_offset_) {
                set_v_offset(saved_v_offset_);
                saved_v_offset_ = 0;
        }

        if (size_finalized_ && scroll_needs_defaults_)
                set_scroll_default();
}

void View::row_item_appearance_changed(bool label, bool content)
{
        if (label)
                header_->update();
        if (content)
                viewport_->update();
}

void View::time_item_appearance_changed(bool label, bool content)
{
        if (label)
                ruler_->update();
        if (content)
                viewport_->update();
}

void View::extents_changed(bool horz, bool vert)
{
        sticky_events_ |=
                (horz ? TraceTreeItemHExtentsChanged : 0) |
                (vert ? TraceTreeItemVExtentsChanged : 0);
        lazy_event_handler_.start();
}

void View::h_scroll_value_changed(int value)
{
        if (updating_scroll_)
                return;

        // Disable sticky scrolling when user moves the horizontal scroll bar
        // during a running acquisition
        if (sticky_scrolling_ && (session_.get_capture_state() == Session::Running)) {
                sticky_scrolling_ = false;
                sticky_scrolling_changed(false);
        }

        const int range = scrollarea_.horizontalScrollBar()->maximum();
        if (range < MaxScrollValue)
                set_offset(scale_ * value);
        else {
                double length = 0;
                Timestamp offset;
                get_scroll_layout(length, offset);
                set_offset(scale_ * length * value / MaxScrollValue);
        }

        ruler_->update();
        viewport_->update();
}

void View::v_scroll_value_changed()
{
        header_->update();
        viewport_->update();
}

void View::signals_changed()
{
        using sigrok::Channel;

        vector< shared_ptr<Channel> > channels;
        shared_ptr<sigrok::Device> sr_dev;

        // Do we need to set the vertical scrollbar to its default position later?
        // We do if there are no traces, i.e. the scroll bar has no range set
        bool reset_scrollbar =
                (scrollarea_.verticalScrollBar()->minimum() ==
                        scrollarea_.verticalScrollBar()->maximum());

        if (!session_.device()) {
                reset_scroll();
                signals_.clear();
        } else {
                sr_dev = session_.device()->device();
                assert(sr_dev);
                channels = sr_dev->channels();
        }

        vector< shared_ptr<TraceTreeItem> > new_top_level_items;

        // Make a list of traces that are being added, and a list of traces
        // that are being removed
        const vector<shared_ptr<Trace>> prev_trace_list = list_by_type<Trace>();
        const set<shared_ptr<Trace>> prev_traces(
                prev_trace_list.begin(), prev_trace_list.end());

        set< shared_ptr<Trace> > traces(signals_.begin(), signals_.end());

#ifdef ENABLE_DECODE
        traces.insert(decode_traces_.begin(), decode_traces_.end());
#endif

        set< shared_ptr<Trace> > add_traces;
        set_difference(traces.begin(), traces.end(),
                prev_traces.begin(), prev_traces.end(),
                inserter(add_traces, add_traces.begin()));

        set< shared_ptr<Trace> > remove_traces;
        set_difference(prev_traces.begin(), prev_traces.end(),
                traces.begin(), traces.end(),
                inserter(remove_traces, remove_traces.begin()));

        // Make a look-up table of sigrok Channels to pulseview Signals
        unordered_map<shared_ptr<data::SignalBase>, shared_ptr<Signal> >
                signal_map;
        for (const shared_ptr<Signal> &sig : signals_)
                signal_map[sig->base()] = sig;

        // Populate channel groups
        if (sr_dev)
                for (auto entry : sr_dev->channel_groups()) {
                        const shared_ptr<sigrok::ChannelGroup> &group = entry.second;

                        if (group->channels().size() <= 1)
                                continue;

                        // Find best trace group to add to
                        TraceTreeItemOwner *owner = find_prevalent_trace_group(
                                group, signal_map);

                        // If there is no trace group, create one
                        shared_ptr<TraceGroup> new_trace_group;
                        if (!owner) {
                                new_trace_group.reset(new TraceGroup());
                                owner = new_trace_group.get();
                        }

                        // Extract traces for the trace group, removing them from
                        // the add list
                        const vector< shared_ptr<Trace> > new_traces_in_group =
                                extract_new_traces_for_channels(group->channels(),
                                        signal_map, add_traces);

                        // Add the traces to the group
                        const pair<int, int> prev_v_extents = owner->v_extents();
                        int offset = prev_v_extents.second - prev_v_extents.first;
                        for (shared_ptr<Trace> trace : new_traces_in_group) {
                                assert(trace);
                                owner->add_child_item(trace);

                                const pair<int, int> extents = trace->v_extents();
                                if (trace->enabled())
                                        offset += -extents.first;
                                trace->force_to_v_offset(offset);
                                if (trace->enabled())
                                        offset += extents.second;
                        }

                        if (new_trace_group) {
                                // Assign proper vertical offsets to each channel in the group
                                new_trace_group->restack_items();

                                // If this is a new group, enqueue it in the new top level
                                // items list
                                if (!new_traces_in_group.empty())
                                        new_top_level_items.push_back(new_trace_group);
                        }
                }

        // Enqueue the remaining logic channels in a group
        vector< shared_ptr<Channel> > logic_channels;
        copy_if(channels.begin(), channels.end(), back_inserter(logic_channels),
                [](const shared_ptr<Channel>& c) {
                        return c->type() == sigrok::ChannelType::LOGIC; });

        const vector< shared_ptr<Trace> > non_grouped_logic_signals =
                extract_new_traces_for_channels(logic_channels, signal_map, add_traces);

        if (non_grouped_logic_signals.size() > 0) {
                const shared_ptr<TraceGroup> non_grouped_trace_group(
                        make_shared<TraceGroup>());
                for (shared_ptr<Trace> trace : non_grouped_logic_signals)
                        non_grouped_trace_group->add_child_item(trace);

                non_grouped_trace_group->restack_items();
                new_top_level_items.push_back(non_grouped_trace_group);
        }

        // Enqueue the remaining channels as free ungrouped traces
        const vector< shared_ptr<Trace> > new_top_level_signals =
                extract_new_traces_for_channels(channels, signal_map, add_traces);
        new_top_level_items.insert(new_top_level_items.end(),
                new_top_level_signals.begin(), new_top_level_signals.end());

        // Enqueue any remaining traces i.e. decode traces
        new_top_level_items.insert(new_top_level_items.end(),
                add_traces.begin(), add_traces.end());

        // Remove any removed traces
        for (shared_ptr<Trace> trace : remove_traces) {
                TraceTreeItemOwner *const owner = trace->owner();
                assert(owner);
                owner->remove_child_item(trace);
        }

        // Remove any empty trace groups
        for (shared_ptr<TraceGroup> group : list_by_type<TraceGroup>())
                if (group->child_items().size() == 0) {
                        remove_child_item(group);
                        group.reset();
                }

        // Add and position the pending top levels items
        int offset = v_extents().second;
        for (auto item : new_top_level_items) {
                add_child_item(item);

                // Position the item after the last item or at the top if there is none
                const pair<int, int> extents = item->v_extents();

                if (item->enabled())
                        offset += -extents.first;

                item->force_to_v_offset(offset);

                if (item->enabled())
                        offset += extents.second;
        }

        update_layout();

        header_->update();
        viewport_->update();

        if (reset_scrollbar)
                set_scroll_default();
}

void View::capture_state_updated(int state)
{
        if (state == Session::Running) {
                set_time_unit(util::TimeUnit::Samples);

                trigger_markers_.clear();

                // Activate "always zoom to fit" if the setting is enabled and we're
                // the main view of this session (other trace views may be used for
                // zooming and we don't want to mess them up)
                GlobalSettings settings;
                bool state = settings.value(GlobalSettings::Key_View_AlwaysZoomToFit).toBool();
                if (is_main_view_ && state) {
                        always_zoom_to_fit_ = true;
                        always_zoom_to_fit_changed(always_zoom_to_fit_);
                }
        }

        if (state == Session::Stopped) {
                // After acquisition has stopped we need to re-calculate the ticks once
                // as it's otherwise done when the user pans or zooms, which is too late
                calculate_tick_spacing();

                // Reset "always zoom to fit", the acquisition has stopped
                if (always_zoom_to_fit_) {
                        // Perform a final zoom-to-fit before disabling
                        zoom_fit(always_zoom_to_fit_);
                        always_zoom_to_fit_ = false;
                        always_zoom_to_fit_changed(always_zoom_to_fit_);
                }
        }
}

void View::data_updated()
{
        if (always_zoom_to_fit_ || sticky_scrolling_) {
                if (!delayed_view_updater_.isActive())
                        delayed_view_updater_.start();
        } else {
                determine_time_unit();
                update_scroll();
                ruler_->update();
                viewport_->update();
        }
}

void View::perform_delayed_view_update()
{
        if (always_zoom_to_fit_) {
                zoom_fit(true);
        } else if (sticky_scrolling_) {
                // Make right side of the view sticky
                double length = 0;
                Timestamp offset;
                get_scroll_layout(length, offset);

                const QSize areaSize = viewport_->size();
                length = max(length - areaSize.width(), 0.0);

                set_offset(scale_ * length);
        }

        determine_time_unit();
        update_scroll();
        ruler_->update();
        viewport_->update();
}

void View::process_sticky_events()
{
        if (sticky_events_ & TraceTreeItemHExtentsChanged)
                update_layout();
        if (sticky_events_ & TraceTreeItemVExtentsChanged) {
                restack_all_trace_tree_items();
                update_scroll();
        }

        // Clear the sticky events
        sticky_events_ = 0;
}

void View::on_hover_point_changed()
{
        const vector<shared_ptr<TraceTreeItem>> trace_tree_items(
                list_by_type<TraceTreeItem>());
        for (shared_ptr<TraceTreeItem> r : trace_tree_items)
                r->hover_point_changed();
}

} // namespace TraceView
} // namespace views
} // namespace pv