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/***************************************************************************
** **
** QCustomPlot, an easy to use, modern plotting widget for Qt **
** Copyright (C) 2011-2018 Emanuel Eichhammer **
** **
** 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 3 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, see http://www.gnu.org/licenses/. **
** **
****************************************************************************
** Author: Emanuel Eichhammer **
** Website/Contact: http://www.qcustomplot.com/ **
** Date: 25.06.18 **
** Version: 2.0.1 **
****************************************************************************/
#include "axistag.h"
AxisTag::AxisTag(QCPAxis *parentAxis) :
QObject(parentAxis),
mAxis(parentAxis)
{
// The dummy tracer serves here as an invisible anchor which always sticks to the right side of
// the axis rect
mDummyTracer = new QCPItemTracer(mAxis->parentPlot());
mDummyTracer->setVisible(false);
mDummyTracer->position->setTypeX(QCPItemPosition::ptAxisRectRatio);
mDummyTracer->position->setTypeY(QCPItemPosition::ptPlotCoords);
mDummyTracer->position->setAxisRect(mAxis->axisRect());
mDummyTracer->position->setAxes(0, mAxis);
mDummyTracer->position->setCoords(1, 0);
// the arrow end (head) is set to move along with the dummy tracer by setting it as its parent
// anchor. Its coordinate system (setCoords) is thus pixels, and this is how the needed horizontal
// offset for the tag of the second y axis is achieved. This horizontal offset gets dynamically
// updated in AxisTag::updatePosition. the arrow "start" is simply set to have the "end" as parent
// anchor. It is given a horizontal offset to the right, which results in a 15 pixel long arrow.
mArrow = new QCPItemLine(mAxis->parentPlot());
mArrow->setLayer("overlay");
mArrow->setClipToAxisRect(false);
mArrow->setHead(QCPLineEnding::esSpikeArrow);
mArrow->end->setParentAnchor(mDummyTracer->position);
mArrow->start->setParentAnchor(mArrow->end);
mArrow->start->setCoords(15, 0);
// The text label is anchored at the arrow start (tail) and has its "position" aligned at the
// left, and vertically centered to the text label box.
mLabel = new QCPItemText(mAxis->parentPlot());
mLabel->setLayer("overlay");
mLabel->setClipToAxisRect(false);
mLabel->setPadding(QMargins(3, 0, 3, 0));
mLabel->setBrush(QBrush(Qt::white));
mLabel->setPen(QPen(Qt::blue));
mLabel->setPositionAlignment(Qt::AlignLeft|Qt::AlignVCenter);
mLabel->position->setParentAnchor(mArrow->start);
}
AxisTag::~AxisTag()
{
if (mDummyTracer)
mDummyTracer->parentPlot()->removeItem(mDummyTracer);
if (mArrow)
mArrow->parentPlot()->removeItem(mArrow);
if (mLabel)
mLabel->parentPlot()->removeItem(mLabel);
}
void AxisTag::setPen(const QPen &pen)
{
mArrow->setPen(pen);
mLabel->setPen(pen);
}
void AxisTag::setBrush(const QBrush &brush)
{
mLabel->setBrush(brush);
}
void AxisTag::setText(const QString &text)
{
mLabel->setText(text);
}
void AxisTag::updatePosition(double value)
{
// since both the arrow and the text label are chained to the dummy tracer (via anchor
// parent-child relationships) it is sufficient to update the dummy tracer coordinates. The
// Horizontal coordinate type was set to ptAxisRectRatio so to keep it aligned at the right side
// of the axis rect, it is always kept at 1. The vertical coordinate type was set to
// ptPlotCoordinates of the passed parent axis, so the vertical coordinate is set to the new
// value.
mDummyTracer->position->setCoords(1, value);
// We want the arrow head to be at the same horizontal position as the axis backbone, even if
// the axis has a certain offset from the axis rect border (like the added second y axis). Thus we
// set the horizontal pixel position of the arrow end (head) to the axis offset (the pixel
// distance to the axis rect border). This works because the parent anchor of the arrow end is
// the dummy tracer, which, as described earlier, is tied to the right axis rect border.
mArrow->end->setCoords(mAxis->offset(), 0);
}
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