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Optimize string truncation algorithm...
Optimize string truncation algorithm Use binary search for truncating strings instead of linear search. Change-Id: I31cde493328e3192a53802aa65dea61975b9e87f Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

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r2539:74f3dbde7a75
r2541:563b21497627
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chartvalueaxisy.cpp
128 lines | 4.0 KiB | text/x-c | CppLexer
/****************************************************************************
**
** Copyright (C) 2013 Digia Plc
** All rights reserved.
** For any questions to Digia, please use contact form at http://qt.digia.com
**
** This file is part of the Qt Commercial Charts Add-on.
**
** $QT_BEGIN_LICENSE$
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.
**
** If you have questions regarding the use of this file, please use
** contact form at http://qt.digia.com
** $QT_END_LICENSE$
**
****************************************************************************/
#include "chartvalueaxisy_p.h"
#include "qabstractaxis.h"
#include "chartpresenter_p.h"
#include "qvalueaxis.h"
#include "abstractchartlayout_p.h"
#include <QGraphicsLayout>
#include <qmath.h>
#include <QDebug>
QTCOMMERCIALCHART_BEGIN_NAMESPACE
ChartValueAxisY::ChartValueAxisY(QValueAxis *axis, QGraphicsItem *item)
: VerticalAxis(axis, item),
m_axis(axis)
{
QObject::connect(m_axis, SIGNAL(tickCountChanged(int)), this, SLOT(handleTickCountChanged(int)));
QObject::connect(m_axis, SIGNAL(labelFormatChanged(QString)), this, SLOT(handleLabelFormatChanged(QString)));
}
ChartValueAxisY::~ChartValueAxisY()
{
}
QVector<qreal> ChartValueAxisY::calculateLayout() const
{
int tickCount = m_axis->tickCount();
Q_ASSERT(tickCount >= 2);
QVector<qreal> points;
points.resize(tickCount);
const QRectF &gridRect = gridGeometry();
const qreal deltaY = gridRect.height() / (qreal(tickCount) - 1.0);
for (int i = 0; i < tickCount; ++i)
points[i] = qreal(i) * -deltaY + gridRect.bottom();
return points;
}
void ChartValueAxisY::updateGeometry()
{
const QVector<qreal> &layout = ChartAxisElement::layout();
if (layout.isEmpty())
return;
setLabels(createValueLabels(min(),max(),layout.size(),m_axis->labelFormat()));
VerticalAxis::updateGeometry();
}
void ChartValueAxisY::handleTickCountChanged(int tick)
{
Q_UNUSED(tick);
QGraphicsLayoutItem::updateGeometry();
if(presenter()) presenter()->layout()->invalidate();
}
void ChartValueAxisY::handleLabelFormatChanged(const QString &format)
{
Q_UNUSED(format);
QGraphicsLayoutItem::updateGeometry();
if(presenter()) presenter()->layout()->invalidate();
}
QSizeF ChartValueAxisY::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
Q_UNUSED(constraint)
QSizeF sh;
QSizeF base = VerticalAxis::sizeHint(which, constraint);
QStringList ticksList = createValueLabels(min(),max(),m_axis->tickCount(),m_axis->labelFormat());
qreal width = 0;
// Height of vertical axis sizeHint indicates the maximum distance labels can extend past
// first and last ticks. Base height is irrelevant.
qreal height = 0;
switch (which) {
case Qt::MinimumSize: {
QRectF boundingRect = ChartPresenter::textBoundingRect(axis()->labelsFont(), "...", axis()->labelsAngle());
width = boundingRect.width() + labelPadding() + base.width() + 1.0;
height = boundingRect.height() / 2.0;
sh = QSizeF(width, height);
break;
}
case Qt::PreferredSize: {
qreal labelWidth = 0.0;
qreal firstHeight = -1.0;
foreach (const QString& s, ticksList) {
QRectF rect = ChartPresenter::textBoundingRect(axis()->labelsFont(), s, axis()->labelsAngle());
labelWidth = qMax(rect.width(), labelWidth);
height = rect.height();
if (firstHeight < 0.0)
firstHeight = height;
}
width = labelWidth + labelPadding() + base.width() + 2.0; //two pixels of tolerance
height = qMax(height, firstHeight) / 2.0;
sh = QSizeF(width, height);
break;
}
default:
break;
}
return sh;
}
#include "moc_chartvalueaxisy_p.cpp"
QTCOMMERCIALCHART_END_NAMESPACE