view.cpp

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/*
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

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

#include <extdef.h>

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

#include <boost/thread/locks.hpp>

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

#include <libsigrokcxx/libsigrokcxx.hpp>

#include "analogsignal.hpp"
#include "decodetrace.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/devices/device.hpp"
#include "pv/data/logic.hpp"
#include "pv/data/logicsegment.hpp"
#include "pv/util.hpp"

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 view {

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};

View::View(Session &session, QWidget *parent) :
    QAbstractScrollArea(parent),
    session_(session),
    viewport_(new Viewport(*this)),
    ruler_(new Ruler(*this)),
    header_(new Header(*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)
{
    connect(horizontalScrollBar(), SIGNAL(valueChanged(int)),
        this, SLOT(h_scroll_value_changed(int)));
    connect(verticalScrollBar(), SIGNAL(valueChanged(int)),
        this, SLOT(v_scroll_value_changed()));

    connect(&session_, SIGNAL(signals_changed()),
        this, SLOT(signals_changed()));
    connect(&session_, SIGNAL(capture_state_changed(int)),
        this, SLOT(capture_state_updated(int)));
    connect(&session_, SIGNAL(data_received()),
        this, SLOT(data_updated()));
    connect(&session_, SIGNAL(frame_ended()),
        this, SLOT(data_updated()));

    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);

    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_;
}

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

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

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

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

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 -verticalScrollBar()->sliderPosition();
}

void View::set_v_offset(int offset)
{
    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
{
    const unordered_set< shared_ptr<Signal> > sigs(session().signals());

    // Make a set of all the visible data objects
    set< shared_ptr<SignalData> > visible_data;
    for (const shared_ptr<Signal> sig : sigs)
        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::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);

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

    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::update_viewport()
{
    assert(viewport_);
    viewport_->update();
    header_->update();
}

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_);

    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>();

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

    updating_scroll_ = true;

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

    updating_scroll_ = false;

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

    const pair<int, int> extents = v_extents();
    verticalScrollBar()->setRange(extents.first - (areaSize.height() / 2),
        extents.second - (areaSize.height() / 2));
}

void View::update_layout()
{
    setViewportMargins(
        header_->sizeHint().width() - pv::view::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();
}

void View::paint_label(QPainter &p, const QRect &rect, bool hover)
{
    (void)p;
    (void)rect;
    (void)hover;
}

QRectF View::label_rect(const QRectF &rect)
{
    (void)rect;
    return QRectF();
}

TraceTreeItemOwner* View::find_prevalent_trace_group(
    const shared_ptr<sigrok::ChannelGroup> &group,
    const unordered_map<shared_ptr<sigrok::Channel>, 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()) {
        const auto iter = signal_map.find(channel);
        if (iter == signal_map.end())
            continue;

        TraceTreeItemOwner *const o = (*iter).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<sigrok::Channel>, shared_ptr<Signal> >
        &signal_map,
    set< shared_ptr<Trace> > &add_list)
{
    vector< shared_ptr<Trace> > filtered_traces;

    for (const auto &channel : channels) {
        const auto map_iter = signal_map.find(channel);
        if (map_iter == signal_map.end())
            continue;

        shared_ptr<Trace> trace = (*map_iter).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) {
        const unordered_set< shared_ptr<Signal> > sigs(session().signals());

        // Check all signals but...
        for (const shared_ptr<Signal> signal : sigs) {
            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);
}

bool View::viewportEvent(QEvent *e)
{
    switch (e->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(e);
    }
}

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

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 = 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<TraceTreeItem> > new_top_level_items;

    const auto device = session_.device();
    if (!device)
        return;

    shared_ptr<sigrok::Device> sr_dev = device->device();
    assert(sr_dev);

    const vector< shared_ptr<Channel> > channels(
        sr_dev->channels());

    // 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());

    const unordered_set< shared_ptr<Signal> > sigs(session_.signals());

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

#ifdef ENABLE_DECODE
    const vector< shared_ptr<DecodeTrace> > decode_traces(
        session().get_decode_signals());
    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<sigrok::Channel>, shared_ptr<Signal> >
        signal_map;
    for (const shared_ptr<Signal> &sig : sigs)
        signal_map[sig->channel()] = sig;

    // Populate channel groups
    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 this is a new group, enqueue it in the new top level
        // items list
        if (!new_traces_in_group.empty() && new_trace_group)
            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);
    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);
    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);
    }

    // Add and position the pending top levels items
    for (auto item : new_top_level_items) {
        add_child_item(item);

        // Position the item after the last present item
        int offset = v_extents().second;
        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();
}

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

        trigger_markers_.clear();
    }

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

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);

    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 view
} // namespace pv