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// SPDX-License-Identifier: GPL-2.0
#include "legend.h"
#include "statscolors.h"
#include "zvalues.h"
#include <QFontMetrics>
#include <QGraphicsSceneMouseEvent>
#include <QGraphicsWidget>
#include <QPen>
static const double legendBorderSize = 2.0;
static const double legendBoxBorderSize = 1.0;
static const double legendBoxBorderRadius = 4.0; // radius of rounded corners
static const double legendBoxScale = 0.8; // 1.0: text-height of the used font
static const double legendInternalBorderSize = 2.0;
static const QColor legendColor(0x00, 0x8e, 0xcc, 192); // Note: fourth argument is opacity
static const QColor legendBorderColor(Qt::black);
Legend::Legend(QGraphicsWidget *chart, const std::vector<QString> &names) :
RoundRectItem(legendBoxBorderRadius, chart), chart(chart),
displayedItems(0), width(0.0), height(0.0)
{
setZValue(ZValues::legend);
entries.reserve(names.size());
int idx = 0;
for (const QString &name: names)
entries.emplace_back(name, idx++, (int)names.size(), this);
// Calculate the height and width of the elements
if (!entries.empty()) {
QFontMetrics fm(entries[0].text->font());
fontHeight = fm.height();
for (Entry &e: entries)
e.width = fontHeight + 2.0 * legendBoxBorderSize +
fm.size(Qt::TextSingleLine, e.text->text()).width();
} else {
// Set to an arbitrary non-zero value, because Coverity doesn't understand
// that we don't use the value as divisor below if entries is empty.
fontHeight = 10.0;
}
setPen(QPen(legendBorderColor, legendBorderSize));
setBrush(QBrush(legendColor));
resize(); // Draw initial legend
}
Legend::Entry::Entry(const QString &name, int idx, int numBins, QGraphicsItem *parent) :
rect(new QGraphicsRectItem(parent)),
text(new QGraphicsSimpleTextItem(name, parent)),
width(0)
{
rect->setZValue(ZValues::legend);
rect->setPen(QPen(legendBorderColor, legendBoxBorderSize));
rect->setBrush(QBrush(binColor(idx, numBins)));
text->setZValue(ZValues::legend);
text->setBrush(QBrush(darkLabelColor));
}
void Legend::hide()
{
for (Entry &e: entries) {
e.rect->hide();
e.text->hide();
}
QGraphicsRectItem::hide();
}
void Legend::resize()
{
if (entries.empty())
return hide();
QSizeF size = chart->size();
// Silly heuristics: make the legend at most half as high and half as wide as the chart.
// Not sure if that makes sense - this might need some optimization.
int maxRows = static_cast<int>(size.height() / 2.0 - 2.0 * legendInternalBorderSize) / fontHeight;
if (maxRows <= 0)
return hide();
int numColumns = ((int)entries.size() - 1) / maxRows + 1;
int numRows = ((int)entries.size() - 1) / numColumns + 1;
double x = legendInternalBorderSize;
displayedItems = 0;
for (int col = 0; col < numColumns; ++col) {
double y = legendInternalBorderSize;
double nextX = x;
for (int row = 0; row < numRows; ++row) {
int idx = col * numRows + row;
if (idx >= (int)entries.size())
break;
entries[idx].pos = QPointF(x, y);
nextX = std::max(nextX, x + entries[idx].width);
y += fontHeight;
++displayedItems;
}
x = nextX;
width = nextX;
if (width >= size.width() / 2.0) // More than half the chart-width -> give up
break;
}
width += legendInternalBorderSize;
height = 2 * legendInternalBorderSize + numRows * fontHeight;
updatePosition();
}
void Legend::updatePosition()
{
if (displayedItems <= 0)
return hide();
// For now, place the legend in the top right corner.
QPointF pos(chart->size().width() - width - 10.0, 10.0);
setRect(QRectF(pos, QSizeF(width, height)));
for (int i = 0; i < displayedItems; ++i) {
QPointF itemPos = pos + entries[i].pos;
QRectF rect(itemPos, QSizeF(fontHeight, fontHeight));
// Decrease box size by legendBoxScale factor
double delta = fontHeight * (1.0 - legendBoxScale) / 2.0;
rect = rect.adjusted(delta, delta, -delta, -delta);
entries[i].rect->setRect(rect);
itemPos.rx() += fontHeight + 2.0 * legendBoxBorderSize;
entries[i].text->setPos(itemPos);
entries[i].rect->show();
entries[i].text->show();
}
for (int i = displayedItems; i < (int)entries.size(); ++i) {
entries[i].rect->hide();
entries[i].text->hide();
}
show();
}
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