Add initial scrolling support with a QAbstractScrollArea

[pulseview.git] / sigview.cpp

/*
 * This file is part of the sigrok 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 <assert.h>
#include <math.h>

#include <boost/foreach.hpp>

#include <QEvent>
#include <QScrollBar>

#include "sigview.h"

#include "logicdata.h"
#include "logicdatasnapshot.h"
#include "sigsession.h"
#include "sigviewport.h"

using namespace boost;
using namespace std;

const double SigView::MaxScale = 1e9;
const double SigView::MinScale = 1e-15;

const int SigView::LabelMarginWidth = 70;
const int SigView::RulerHeight = 30;

SigView::SigView(SigSession &session, QWidget *parent) :
	QAbstractScrollArea(parent),
	_session(session),
	_viewport(new SigViewport(*this)),
	_data_length(0),
	_scale(1e-6),
	_offset(0),
	_v_offset(0)
{
	connect(horizontalScrollBar(), SIGNAL(valueChanged(int)),
		this, SLOT(h_scroll_value_changed(int)));
	connect(verticalScrollBar(), SIGNAL(valueChanged(int)),
		this, SLOT(v_scroll_value_changed(int)));
	connect(&_session, SIGNAL(data_updated()),
		this, SLOT(data_updated()));
	setViewport(_viewport);
}

double SigView::scale() const
{
	return _scale;
}

double SigView::offset() const
{
	return _offset;
}

int SigView::v_offset() const
{
	return _v_offset;
}

void SigView::zoom(double steps)
{
	zoom(steps, (width() - LabelMarginWidth) / 2);
}

void SigView::set_scale_offset(double scale, double offset)
{
	_scale = scale;
	_offset = offset;
	update_scroll();
	_viewport->update();
}

void SigView::update_scroll()
{
	assert(_viewport);

	const QSize areaSize = _viewport->size();

	// Set the horizontal scroll bar
	double length = 0, offset = 0;
	const shared_ptr<SignalData> sig_data = _session.get_data();
	if(sig_data) {
		length = _data_length /
			(sig_data->get_samplerate() * _scale);
		offset = _offset / _scale;
	}

	horizontalScrollBar()->setPageStep(areaSize.width());
	horizontalScrollBar()->setRange(0,
		max((int)(length - areaSize.width()), 0));
	horizontalScrollBar()->setSliderPosition(offset);

	// Set the vertical scrollbar
	verticalScrollBar()->setPageStep(areaSize.height());
	verticalScrollBar()->setRange(0,
		_viewport->get_total_height() - areaSize.height());
}

void SigView::zoom(double steps, int offset)
{
	const double cursor_offset = _offset + _scale * offset;
	_scale *= pow(3.0/2.0, -steps);
	_scale = max(min(_scale, MaxScale), MinScale);
	_offset = cursor_offset - _scale * offset;
	_viewport->update();
	update_scroll();
}

bool SigView::viewportEvent(QEvent *e)
{
	switch(e->type()) {
	case QEvent::Paint:
	case QEvent::MouseButtonPress:
	case QEvent::MouseButtonRelease:
	case QEvent::MouseButtonDblClick:
	case QEvent::MouseMove:
	case QEvent::Wheel:
		return false;

	default:
		return QAbstractScrollArea::viewportEvent(e);
	}
}

void SigView::resizeEvent(QResizeEvent *e)
{
	update_scroll();
}

void SigView::h_scroll_value_changed(int value)
{
	_offset = _scale * value;
	_viewport->update();
}

void SigView::v_scroll_value_changed(int value)
{
	_v_offset = value;
	_viewport->update();
}

void SigView::data_updated()
{
	// Get the new data length
	_data_length = 0;
	shared_ptr<LogicData> sig_data = _session.get_data();
	if(sig_data) {
		deque< shared_ptr<LogicDataSnapshot> > &snapshots =
			sig_data->get_snapshots();
		BOOST_FOREACH(shared_ptr<LogicDataSnapshot> s, snapshots)
			if(s)
				_data_length = max(_data_length,
					s->get_sample_count());
	}

	// Update the scroll bars
	update_scroll();

	// Repaint the view
	_viewport->update();
}