ruler.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
 */

#include <extdef.h>

#include <QApplication>
#include <QFontMetrics>
#include <QMouseEvent>

#include "ruler.hpp"
#include "view.hpp"

using namespace Qt;

using std::shared_ptr;
using std::vector;

namespace pv {
namespace view {

const float Ruler::RulerHeight = 2.5f; // x Text Height
const int Ruler::MinorTickSubdivision = 4;

const float Ruler::HoverArrowSize = 0.5f; // x Text Height

Ruler::Ruler(View &parent) :
    MarginWidget(parent)
{
    setMouseTracking(true);

    connect(&view_, SIGNAL(hover_point_changed()),
        this, SLOT(hover_point_changed()));
    connect(&view_, SIGNAL(offset_changed()),
        this, SLOT(invalidate_tick_position_cache()));
    connect(&view_, SIGNAL(scale_changed()),
        this, SLOT(invalidate_tick_position_cache()));
    connect(&view_, SIGNAL(tick_prefix_changed()),
        this, SLOT(invalidate_tick_position_cache()));
    connect(&view_, SIGNAL(tick_precision_changed()),
        this, SLOT(invalidate_tick_position_cache()));
    connect(&view_, SIGNAL(tick_period_changed()),
        this, SLOT(invalidate_tick_position_cache()));
    connect(&view_, SIGNAL(time_unit_changed()),
        this, SLOT(invalidate_tick_position_cache()));
}

QSize Ruler::sizeHint() const
{
    const int text_height = calculate_text_height();
    return QSize(0, RulerHeight * text_height);
}

QSize Ruler::extended_size_hint() const
{
    QRectF max_rect;
    std::vector< std::shared_ptr<TimeItem> > items(view_.time_items());
    for (auto &i : items)
        max_rect = max_rect.united(i->label_rect(QRect()));
    return QSize(0, sizeHint().height() - max_rect.top() / 2 +
        ViewItem::HighlightRadius);
}

QString Ruler::format_time_with_distance(
    const pv::util::Timestamp& distance,
    const pv::util::Timestamp& t,
    pv::util::SIPrefix prefix,
    pv::util::TimeUnit unit,
    unsigned precision,
    bool sign)
{
    const unsigned limit = 60;

    if (t.is_zero())
        return "0";

    // If we have to use samples then we have no alternative formats
    if (unit == pv::util::TimeUnit::Samples)
        return pv::util::format_time_si_adjusted(t, prefix, precision, "sa", sign);

    // View zoomed way out -> low precision (0), big distance (>=60s)
    // -> DD:HH:MM
    if ((precision == 0) && (distance >= limit))
        return pv::util::format_time_minutes(t, 0, sign);

    // View in "normal" range -> medium precision, medium step size
    // -> HH:MM:SS.mmm... or xxxx (si unit) if less than limit seconds
    // View zoomed way in -> high precision (>3), low step size (<1s)
    // -> HH:MM:SS.mmm... or xxxx (si unit) if less than limit seconds
    if (abs(t) < limit)
        return pv::util::format_time_si_adjusted(t, prefix, precision, "s", sign);
    else
        return pv::util::format_time_minutes(t, precision, sign);
}

vector< shared_ptr<ViewItem> > Ruler::items()
{
    const vector< shared_ptr<TimeItem> > time_items(view_.time_items());
    return vector< shared_ptr<ViewItem> >(
        time_items.begin(), time_items.end());
}

shared_ptr<ViewItem> Ruler::get_mouse_over_item(const QPoint &pt)
{
    const vector< shared_ptr<TimeItem> > items(view_.time_items());
    for (auto i = items.rbegin(); i != items.rend(); i++)
        if ((*i)->enabled() && (*i)->label_rect(rect()).contains(pt))
            return *i;
    return nullptr;
}

void Ruler::paintEvent(QPaintEvent*)
{
    if (!tick_position_cache_) {
        auto ffunc = [this](const pv::util::Timestamp& t) {
            return format_time_with_distance(
                this->view_.tick_period(),
                t,
                this->view_.tick_prefix(),
                this->view_.time_unit(),
                this->view_.tick_precision());
        };

        tick_position_cache_ = calculate_tick_positions(
            view_.tick_period(),
            view_.offset(),
            view_.scale(),
            width(),
            ffunc);
    }

    const int ValueMargin = 3;

    const int text_height = calculate_text_height();
    const int ruler_height = RulerHeight * text_height;
    const int major_tick_y1 = text_height + ValueMargin * 2;
    const int minor_tick_y1 = (major_tick_y1 + ruler_height) / 2;

    QPainter p(this);

    // Draw the tick marks
    p.setPen(palette().color(foregroundRole()));

    for (const auto& tick: tick_position_cache_->major) {
        p.drawText(tick.first, ValueMargin, 0, text_height,
                AlignCenter | AlignTop | TextDontClip, tick.second);
        p.drawLine(QPointF(tick.first, major_tick_y1),
            QPointF(tick.first, ruler_height));
    }

    for (const auto& tick: tick_position_cache_->minor) {
        p.drawLine(QPointF(tick, minor_tick_y1),
                QPointF(tick, ruler_height));
    }

    // Draw the hover mark
    draw_hover_mark(p, text_height);

    p.setRenderHint(QPainter::Antialiasing);

    // The cursor labels are not drawn with the arrows exactly on the
    // bottom line of the widget, because then the selection shadow
    // would be clipped away.
    const QRect r = rect().adjusted(0, 0, 0, -ViewItem::HighlightRadius);

    // Draw the items
    const vector< shared_ptr<TimeItem> > items(view_.time_items());
    for (auto &i : items) {
        const bool highlight = !item_dragging_ &&
            i->label_rect(r).contains(mouse_point_);
        i->paint_label(p, r, highlight);
    }
}

Ruler::TickPositions Ruler::calculate_tick_positions(
    const pv::util::Timestamp& major_period,
    const pv::util::Timestamp& offset,
    const double scale,
    const int width,
    std::function<QString(const pv::util::Timestamp&)> format_function)
{
    TickPositions tp;

    const pv::util::Timestamp minor_period = major_period / MinorTickSubdivision;
    const pv::util::Timestamp first_major_division = floor(offset / major_period);
    const pv::util::Timestamp first_minor_division = ceil(offset / minor_period);
    const pv::util::Timestamp t0 = first_major_division * major_period;

    int division = (round(first_minor_division -
        first_major_division * MinorTickSubdivision)).convert_to<int>() - 1;

    double x;

    do {
        pv::util::Timestamp t = t0 + division * minor_period;
        x = ((t - offset) / scale).convert_to<double>();

        if (division % MinorTickSubdivision == 0) {
            // Recalculate 't' without using 'minor_period' which is a fraction
            t = t0 + division / MinorTickSubdivision * major_period;
            tp.major.emplace_back(x, format_function(t));
        } else {
            tp.minor.emplace_back(x);
        }

        division++;
    } while (x < width);

    return tp;
}

void Ruler::mouseDoubleClickEvent(QMouseEvent *e)
{
    view_.add_flag(view_.offset() + ((double)e->x() + 0.5) * view_.scale());
}

void Ruler::draw_hover_mark(QPainter &p, int text_height)
{
    const int x = view_.hover_point().x();

    if (x == -1)
        return;

    p.setPen(QPen(Qt::NoPen));
    p.setBrush(QBrush(palette().color(foregroundRole())));

    const int b = RulerHeight * text_height;
    const float hover_arrow_size = HoverArrowSize * text_height;
    const QPointF points[] = {
        QPointF(x, b),
        QPointF(x - hover_arrow_size, b - hover_arrow_size),
        QPointF(x + hover_arrow_size, b - hover_arrow_size)
    };
    p.drawPolygon(points, countof(points));
}

int Ruler::calculate_text_height() const
{
    return QFontMetrics(font()).ascent();
}

void Ruler::hover_point_changed()
{
    update();
}

void Ruler::invalidate_tick_position_cache()
{
    tick_position_cache_ = boost::none;
}

void Ruler::resizeEvent(QResizeEvent*)
{
    // the tick calculation depends on the width of this widget
    invalidate_tick_position_cache();
}

} // namespace view
} // namespace pv