Automatically choose the best annotation based on visual width

[pulseview.git] / pv / view / decode / annotation.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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

extern "C" {
#include <libsigrokdecode/libsigrokdecode.h>
}

#include <extdef.h>

#include <algorithm>

#include <QPainter>

#include "annotation.h"

using namespace boost;
using namespace std;

namespace pv {
namespace view {
namespace decode {

const double Annotation::EndCapWidth = 5;

Annotation::Annotation(const srd_proto_data *const pdata) :
	_start_sample(pdata->start_sample),
	_end_sample(pdata->end_sample)
{
	const char *const *annotations = (char**)pdata->data;
	while(*annotations) {
		_annotations.push_back(QString(*annotations));
		annotations++;
	}
}

void Annotation::paint(QPainter &p, QColor fill, QColor outline,
	QColor text_color, int text_height, int left, int right,
	double samples_per_pixel, double pixels_offset, int y)
{
	const int h = (text_height * 3) / 2;

	const double start = _start_sample / samples_per_pixel -
		pixels_offset;
	const double end = _end_sample / samples_per_pixel -
		pixels_offset;

	if (start > right || end < left)
		return;

	const double cap_width = min((end - start) / 2, EndCapWidth);

	QPointF pts[] = {
		QPointF(start, y + .5f),
		QPointF(start + cap_width, y + .5f - h / 2),
		QPointF(end - cap_width, y + .5f - h / 2),
		QPointF(end, y + .5f),
		QPointF(end - cap_width, y + .5f + h / 2),
		QPointF(start + cap_width, y + .5f + h / 2)
	};

	p.setPen(outline);
	p.setBrush(fill);
	p.drawConvexPolygon(pts, countof(pts));

	if (_annotations.empty())
		return;

	QRectF rect(start + cap_width, y - h / 2,
		end - start - cap_width * 2, h);
	p.setPen(text_color);

	// Try to find an annotation that will fit
	QString best_annotation;
	int best_width = 0;

	BOOST_FOREACH(QString &a, _annotations) {
		const int w = p.boundingRect(QRectF(), 0, a).width();
		if (w <= rect.width() && w > best_width)
			best_annotation = a, best_width = w;
	}

	if (best_annotation.isEmpty())
		best_annotation = _annotations.back();

	// If not ellide the last in the list
	p.drawText(rect, Qt::AlignCenter, p.fontMetrics().elidedText(
		best_annotation, Qt::ElideRight, rect.width()));
}

} // namespace decode
} // namespace view
} // namespace pv