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Fix category axis label positioning....
Fix category axis label positioning. Labels are now centered on the visible portion of the category, if some part of the category is off-grid. If the label doesn't fit into the remaining part, it is not shown. Task-number: QTRD-1934 Reviewed-by: Mika Salmela

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r2446:e5bdddebc98a
r2446:e5bdddebc98a
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horizontalaxis.cpp
218 lines | 8.0 KiB | text/x-c | CppLexer
/ src / axis / horizontalaxis.cpp
/****************************************************************************
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** This file is part of the Qt Commercial Charts Add-on.
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#include "horizontalaxis_p.h"
#include "qabstractaxis.h"
#include <QFontMetrics>
#include <qmath.h>
#include <QDebug>
QTCOMMERCIALCHART_BEGIN_NAMESPACE
HorizontalAxis::HorizontalAxis(QAbstractAxis *axis, QGraphicsItem* item , bool intervalAxis)
: ChartAxis(axis, item, intervalAxis)
{
}
HorizontalAxis::~HorizontalAxis()
{
}
void HorizontalAxis::updateGeometry()
{
const QVector<qreal>& layout = ChartAxis::layout();
if (layout.isEmpty())
return;
QStringList labelList = labels();
QList<QGraphicsItem *> lines = lineItems();
QList<QGraphicsItem *> labels = labelItems();
QList<QGraphicsItem *> shades = shadeItems();
QList<QGraphicsItem *> axis = arrowItems();
QGraphicsSimpleTextItem* 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 *>(axis.at(0));
if (alignment() == Qt::AlignTop)
arrowItem->setLine(gridRect.left(), axisRect.bottom(), gridRect.right(), axisRect.bottom());
else if (alignment() == Qt::AlignBottom)
arrowItem->setLine(gridRect.left(), axisRect.top(), gridRect.right(), axisRect.top());
qreal width = 0;
QFontMetrics fn(font());
//title
int titlePad = 0;
QRectF titleBoundingRect;
if (!titleText().isEmpty() && titleItem()->isVisible()) {
QFontMetrics fn(title->font());
int size(0);
size = gridRect.width();
QString titleText = this->titleText();
if (fn.boundingRect(titleText).width() > size) {
QString string = titleText + "...";
while (fn.boundingRect(string).width() > size && string.length() > 3)
string.remove(string.length() - 4, 1);
title->setText(string);
} else {
title->setText(titleText);
}
titlePad = titlePadding();
titleBoundingRect = title->boundingRect();
QPointF center = gridRect.center() - titleBoundingRect.center();
if (alignment() == Qt::AlignTop) {
title->setPos(center.x(), axisRect.top() + titlePad);
} else if (alignment() == Qt::AlignBottom) {
title->setPos(center.x(), axisRect.bottom() - titleBoundingRect.height() - titlePad);
}
}
for (int i = 0; i < layout.size(); ++i) {
//items
QGraphicsLineItem *gridItem = static_cast<QGraphicsLineItem*>(lines.at(i));
QGraphicsLineItem *tickItem = static_cast<QGraphicsLineItem*>(axis.at(i + 1));
QGraphicsSimpleTextItem *labelItem = static_cast<QGraphicsSimpleTextItem *>(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 = labelBoundingRect(fn, text);
qreal size = axisRect.bottom() - axisRect.top() - labelPadding() - titleBoundingRect.height() - (titlePad * 2);
if (boundingRect.height() > size) {
QString label = text + "...";
while (boundingRect.height() >= size && label.length() > 3) {
label.remove(label.length() - 4, 1);
boundingRect = labelBoundingRect(fn, label);
}
labelItem->setText(label);
} else {
labelItem->setText(text);
}
//label transformation origin point
const QRectF& rect = labelItem->boundingRect();
QPointF center = rect.center();
labelItem->setTransformOriginPoint(center.x(), center.y());
int heightDiff = rect.height() - boundingRect.height();
//ticks and label position
if (alignment() == Qt::AlignTop) {
labelItem->setPos(layout[i] - center.x(), axisRect.bottom() - rect.height() + (heightDiff / 2) - labelPadding());
tickItem->setLine(layout[i], axisRect.bottom(), layout[i], axisRect.bottom() - labelPadding());
} else if (alignment() == Qt::AlignBottom) {
labelItem->setPos(layout[i] - center.x(), axisRect.top() - (heightDiff / 2) + 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));
rectItem->setRect(layout[i - 1], gridRect.top(), layout[i] - layout[i - 1], gridRect.height());
}
// 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);
QFontMetrics fn(titleFont());
QSizeF sh(0,0);
if (titleText().isEmpty() || !titleItem()->isVisible())
return sh;
switch (which) {
case Qt::MinimumSize:
sh = QSizeF(fn.boundingRect("...").width(), fn.height() + (titlePadding() * 2));
break;
case Qt::MaximumSize:
case Qt::PreferredSize:
sh = QSizeF(fn.boundingRect(axis()->titleText()).width(), fn.height() + (titlePadding() * 2));
break;
default:
break;
}
return sh;
}
QTCOMMERCIALCHART_END_NAMESPACE