analogsignal.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 <cassert>
#include <cmath>
#include <cstdlib>
#include <limits>

#include "analogsignal.hpp"
#include "pv/data/analog.hpp"
#include "pv/data/analogsegment.hpp"
#include "pv/view/view.hpp"

#include <libsigrokcxx/libsigrokcxx.hpp>

using std::max;
using std::make_pair;
using std::min;
using std::shared_ptr;
using std::deque;

using sigrok::Channel;

namespace pv {
namespace view {

const int AnalogSignal::NominalHeight = 80;

const QColor AnalogSignal::SignalColours[4] = {
    QColor(0xC4, 0xA0, 0x00),   // Yellow
    QColor(0x87, 0x20, 0x7A),   // Magenta
    QColor(0x20, 0x4A, 0x87),   // Blue
    QColor(0x4E, 0x9A, 0x06)    // Green
};

const float AnalogSignal::EnvelopeThreshold = 256.0f;

AnalogSignal::AnalogSignal(
    pv::Session &session,
    shared_ptr<Channel> channel,
    shared_ptr<data::Analog> data) :
    Signal(session, channel),
    data_(data),
    scale_index_(0),
    scale_index_drag_offset_(0)
{
    set_colour(SignalColours[channel_->index() % countof(SignalColours)]);
}

AnalogSignal::~AnalogSignal()
{
}

shared_ptr<pv::data::SignalData> AnalogSignal::data() const
{
    return data_;
}

shared_ptr<pv::data::Analog> AnalogSignal::analog_data() const
{
    return data_;
}

std::pair<int, int> AnalogSignal::v_extents() const
{
    const int h = NominalHeight / 2;
    return make_pair(-h, h);
}

int AnalogSignal::scale_handle_offset() const
{
    return ((scale_index_drag_offset_ - scale_index_) *
        NominalHeight / 4) - NominalHeight / 2;
}

void AnalogSignal::scale_handle_dragged(int offset)
{
    scale_index_ = scale_index_drag_offset_ -
        (offset + NominalHeight / 2) / (NominalHeight / 4);
}

void AnalogSignal::scale_handle_drag_release()
{
    scale_index_drag_offset_ = scale_index_;
}

void AnalogSignal::paint_back(QPainter &p, const ViewItemPaintParams &pp)
{
    if (channel_->enabled()) {
        Trace::paint_back(p, pp);
        paint_axis(p, pp, get_visual_y());
    }
}

void AnalogSignal::paint_mid(QPainter &p, const ViewItemPaintParams &pp)
{
    assert(data_);
    assert(owner_);

    const int y = get_visual_y();

    if (!channel_->enabled())
        return;

    const deque< shared_ptr<pv::data::AnalogSegment> > &segments =
        data_->analog_segments();
    if (segments.empty())
        return;

    const shared_ptr<pv::data::AnalogSegment> &segment =
        segments.front();

    const double pixels_offset = pp.pixels_offset();
    const double samplerate = max(1.0, segment->samplerate());
    const pv::util::Timestamp& start_time = segment->start_time();
    const int64_t last_sample = segment->get_sample_count() - 1;
    const double samples_per_pixel = samplerate * pp.scale();
    const pv::util::Timestamp start = samplerate * (pp.offset() - start_time);
    const pv::util::Timestamp end = start + samples_per_pixel * pp.width();

    const int64_t start_sample = min(max(floor(start).convert_to<int64_t>(),
        (int64_t)0), last_sample);
    const int64_t end_sample = min(max((ceil(end) + 1).convert_to<int64_t>(),
        (int64_t)0), last_sample);

    if (samples_per_pixel < EnvelopeThreshold)
        paint_trace(p, segment, y, pp.left(),
            start_sample, end_sample,
            pixels_offset, samples_per_pixel);
    else
        paint_envelope(p, segment, y, pp.left(),
            start_sample, end_sample,
            pixels_offset, samples_per_pixel);
}

void AnalogSignal::paint_trace(QPainter &p,
    const shared_ptr<pv::data::AnalogSegment> &segment,
    int y, int left, const int64_t start, const int64_t end,
    const double pixels_offset, const double samples_per_pixel)
{
    const float scale = this->scale();
    const int64_t sample_count = end - start;

    const float *const samples = segment->get_samples(start, end);
    assert(samples);

    p.setPen(colour_);

    QPointF *points = new QPointF[sample_count];
    QPointF *point = points;

    for (int64_t sample = start; sample != end; sample++) {
        const float x = (sample / samples_per_pixel -
            pixels_offset) + left;
        *point++ = QPointF(x,
            y - samples[sample - start] * scale);
    }

    p.drawPolyline(points, point - points);

    delete[] samples;
    delete[] points;
}

void AnalogSignal::paint_envelope(QPainter &p,
    const shared_ptr<pv::data::AnalogSegment> &segment,
    int y, int left, const int64_t start, const int64_t end,
    const double pixels_offset, const double samples_per_pixel)
{
    using pv::data::AnalogSegment;

    const float scale = this->scale();

    AnalogSegment::EnvelopeSection e;
    segment->get_envelope_section(e, start, end, samples_per_pixel);

    if (e.length < 2)
        return;

    p.setPen(QPen(Qt::NoPen));
    p.setBrush(colour_);

    QRectF *const rects = new QRectF[e.length];
    QRectF *rect = rects;

    for (uint64_t sample = 0; sample < e.length-1; sample++) {
        const float x = ((e.scale * sample + e.start) /
            samples_per_pixel - pixels_offset) + left;
        const AnalogSegment::EnvelopeSample *const s =
            e.samples + sample;

        // We overlap this sample with the next so that vertical
        // gaps do not appear during steep rising or falling edges
        const float b = y - max(s->max, (s+1)->min) * scale;
        const float t = y - min(s->min, (s+1)->max) * scale;

        float h = b - t;
        if (h >= 0.0f && h <= 1.0f)
            h = 1.0f;
        if (h <= 0.0f && h >= -1.0f)
            h = -1.0f;

        *rect++ = QRectF(x, t, 1.0f, h);
    }

    p.drawRects(rects, e.length);

    delete[] rects;
    delete[] e.samples;
}

float AnalogSignal::scale() const
{
    const float seq[] = {1.0f, 2.0f, 5.0f};
    const int offset = std::numeric_limits<int>::max() / (2 * countof(seq));
    const std::div_t d = std::div(
        (int)(scale_index_ + countof(seq) * offset),
        countof(seq));
    return powf(10.0f, d.quot - offset) * seq[d.rem];
}

} // namespace view
} // namespace pv