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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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r2540:18da5db7d538
r2541:563b21497627
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horizontalaxis.cpp
223 lines | 8.8 KiB | text/x-c | CppLexer
/ src / axis / horizontalaxis.cpp
/****************************************************************************
**
** 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 "horizontalaxis_p.h"
#include "qabstractaxis_p.h"
#include "chartpresenter_p.h"
#include <qmath.h>
#include <QDebug>
QTCOMMERCIALCHART_BEGIN_NAMESPACE
HorizontalAxis::HorizontalAxis(QAbstractAxis *axis, QGraphicsItem *item, bool intervalAxis)
: CartesianChartAxis(axis, item, intervalAxis)
{
}
HorizontalAxis::~HorizontalAxis()
{
}
void HorizontalAxis::updateGeometry()
{
const QVector<qreal> &layout = ChartAxisElement::layout();
if (layout.isEmpty())
return;
QStringList labelList = labels();
QList<QGraphicsItem *> lines = gridItems();
QList<QGraphicsItem *> labels = labelItems();
QList<QGraphicsItem *> shades = shadeItems();
QList<QGraphicsItem *> arrow = arrowItems();
QGraphicsTextItem *title = titleItem();
Q_ASSERT(labels.size() == labelList.size());
Q_ASSERT(layout.size() == labelList.size());
const QRectF &axisRect = axisGeometry();
const QRectF &gridRect = gridGeometry();
//arrow
QGraphicsLineItem *arrowItem = static_cast<QGraphicsLineItem *>(arrow.at(0));
if (axis()->alignment() == Qt::AlignTop)
arrowItem->setLine(gridRect.left(), axisRect.bottom(), gridRect.right(), axisRect.bottom());
else if (axis()->alignment() == Qt::AlignBottom)
arrowItem->setLine(gridRect.left(), axisRect.top(), gridRect.right(), axisRect.top());
qreal width = 0;
//title
QRectF titleBoundingRect;
QString titleText = axis()->titleText();
qreal availableSpace = axisRect.height() - labelPadding();
if (!titleText.isEmpty() && titleItem()->isVisible()) {
availableSpace -= titlePadding() * 2.0;
qreal minimumLabelHeight = ChartPresenter::textBoundingRect(axis()->labelsFont(), "...").height();
QString truncatedTitle = ChartPresenter::truncatedText(axis()->titleFont(), titleText, qreal(0.0),
gridRect.width(), Qt::Horizontal, titleBoundingRect);
qreal titleSpace = availableSpace - minimumLabelHeight;
if (titleSpace < titleBoundingRect.height()) {
// Need to also truncate title vertically (multiline title)
bool skip = false;
if (truncatedTitle.endsWith("...")) {
if (truncatedTitle.size() == 3)
skip = true; // Already truncated to minimum
else
truncatedTitle.chop(3);
}
if (!skip)
truncatedTitle = ChartPresenter::truncatedText(axis()->titleFont(), truncatedTitle, qreal(0.0),
titleSpace, Qt::Vertical, titleBoundingRect);
}
title->setHtml(truncatedTitle);
titleBoundingRect = title->boundingRect();
QPointF center = gridRect.center() - titleBoundingRect.center();
if (axis()->alignment() == Qt::AlignTop)
title->setPos(center.x(), axisRect.top() + titlePadding());
else if (axis()->alignment() == Qt::AlignBottom)
title->setPos(center.x(), axisRect.bottom() - titleBoundingRect.height() - titlePadding());
availableSpace -= titleBoundingRect.height();
}
for (int i = 0; i < layout.size(); ++i) {
//items
QGraphicsLineItem *gridItem = static_cast<QGraphicsLineItem*>(lines.at(i));
QGraphicsLineItem *tickItem = static_cast<QGraphicsLineItem*>(arrow.at(i + 1));
QGraphicsTextItem *labelItem = static_cast<QGraphicsTextItem *>(labels.at(i));
//grid line
gridItem->setLine(layout[i], gridRect.top(), layout[i], gridRect.bottom());
//label text wrapping
QString text = labelList.at(i);
QRectF boundingRect;
labelItem->setHtml(ChartPresenter::truncatedText(axis()->labelsFont(), text, axis()->labelsAngle(),
availableSpace, Qt::Vertical, boundingRect));
//label transformation origin point
const QRectF& rect = labelItem->boundingRect();
QPointF center = rect.center();
labelItem->setTransformOriginPoint(center.x(), center.y());
qreal heightDiff = rect.height() - boundingRect.height();
//ticks and label position
if (axis()->alignment() == Qt::AlignTop) {
labelItem->setPos(layout[i] - center.x(), axisRect.bottom() - rect.height() + (heightDiff / 2.0) - labelPadding());
tickItem->setLine(layout[i], axisRect.bottom(), layout[i], axisRect.bottom() - labelPadding());
} else if (axis()->alignment() == Qt::AlignBottom) {
labelItem->setPos(layout[i] - center.x(), axisRect.top() - (heightDiff / 2.0) + labelPadding());
tickItem->setLine(layout[i], axisRect.top(), layout[i], axisRect.top() + labelPadding());
}
//label in between
bool forceHide = false;
if (intervalAxis() && (i + 1) != layout.size()) {
qreal leftBound = qMax(layout[i], gridRect.left());
qreal rightBound = qMin(layout[i + 1], gridRect.right());
const qreal delta = rightBound - leftBound;
// Hide label in case visible part of the category at the grid edge is too narrow
if (delta < boundingRect.width()
&& (leftBound == gridRect.left() || rightBound == gridRect.right())) {
forceHide = true;
} else {
labelItem->setPos(leftBound + (delta / 2.0) - center.x(), labelItem->pos().y());
}
}
//label overlap detection - compensate one pixel for rounding errors
if (labelItem->pos().x() < width || forceHide ||
labelItem->pos().x() < (axisRect.left() - 1.0) ||
(labelItem->pos().x() + boundingRect.width() - 1.0) > axisRect.right()){
labelItem->setVisible(false);
} else {
labelItem->setVisible(true);
width = boundingRect.width() + labelItem->pos().x();
}
//shades
if ((i + 1) % 2 && i > 1) {
QGraphicsRectItem *rectItem = static_cast<QGraphicsRectItem *>(shades.at(i / 2 - 1));
qreal leftBound = qMax(layout[i - 1], gridRect.left());
qreal rightBound = qMin(layout[i], gridRect.right());
rectItem->setRect(leftBound, gridRect.top(), rightBound - leftBound, gridRect.height());
if (rectItem->rect().width() <= 0.0)
rectItem->setVisible(false);
else
rectItem->setVisible(true);
}
// check if the grid line and the axis tick should be shown
qreal x = gridItem->line().p1().x();
if (x < gridRect.left() || x > gridRect.right()) {
gridItem->setVisible(false);
tickItem->setVisible(false);
} else {
gridItem->setVisible(true);
tickItem->setVisible(true);
}
}
//begin/end grid line in case labels between
if (intervalAxis()) {
QGraphicsLineItem *gridLine;
gridLine = static_cast<QGraphicsLineItem *>(lines.at(layout.size()));
gridLine->setLine(gridRect.right(), gridRect.top(), gridRect.right(), gridRect.bottom());
gridLine->setVisible(true);
gridLine = static_cast<QGraphicsLineItem*>(lines.at(layout.size()+1));
gridLine->setLine(gridRect.left(), gridRect.top(), gridRect.left(), gridRect.bottom());
gridLine->setVisible(true);
}
}
QSizeF HorizontalAxis::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
Q_UNUSED(constraint);
QSizeF sh(0,0);
if (axis()->titleText().isEmpty() || !titleItem()->isVisible())
return sh;
switch (which) {
case Qt::MinimumSize: {
QRectF titleRect = ChartPresenter::textBoundingRect(axis()->titleFont(), "...");
sh = QSizeF(titleRect.width(), titleRect.height() + (titlePadding() * 2.0));
break;
}
case Qt::MaximumSize:
case Qt::PreferredSize: {
QRectF titleRect = ChartPresenter::textBoundingRect(axis()->titleFont(), axis()->titleText());
sh = QSizeF(titleRect.width(), titleRect.height() + (titlePadding() * 2.0));
break;
}
default:
break;
}
return sh;
}
QTCOMMERCIALCHART_END_NAMESPACE