subsurface/desktop-widgets/statswidget.cpp
Dirk Hohndel 2368a183e1 Qt6: prevent QML object from being garbage collected
It appears that the QML object that is created when assigning the source
to the StatsView in the ui can be garbage collected and therefore
destroyed and re-instantiated without our knowledge. So instead of
trying to keep a pointer around, we end up looking up the object address
when needed.
We still ask the JS code to not garbage collect the object - but that
clearly isn't enough to prevent it from being destroyed when the parent
widget changes.

Without this fix opening the statistics will crash with Qt6.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2022-03-12 08:28:32 -08:00

265 lines
8.2 KiB
C++

// SPDX-License-Identifier: GPL-2.0
#include "statswidget.h"
#include "mainwindow.h"
#include "stats/statsview.h"
#include <QCheckBox>
#include <QPainter>
#include <QStyledItemDelegate>
#include <QQmlEngine>
class ChartItemDelegate : public QStyledItemDelegate {
private:
void paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const override;
QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override;
};
// Number of pixels that non-toplevel items are indented
static int indent(const QFontMetrics &fm)
{
#if QT_VERSION < QT_VERSION_CHECK(5, 11, 0)
return 4 * fm.width('-');
#else
return 4 * fm.horizontalAdvance('-');
#endif
}
static const int iconSpace = 2; // Number of pixels between icon and text
static const int topSpace = 2; // Number of pixels above icon
void ChartItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const
{
QFont font = index.data(Qt::FontRole).value<QFont>();
QFontMetrics fm(font);
QString name = index.data(ChartListModel::ChartNameRole).value<QString>();
painter->setFont(font);
QRect rect = option.rect;
if (option.state & QStyle::State_Selected) {
painter->save();
painter->setBrush(option.palette.highlight());
painter->setPen(Qt::NoPen);
painter->drawRect(rect);
painter->restore();
}
bool isHeader = index.data(ChartListModel::IsHeaderRole).value<bool>();
if (!isHeader)
rect.translate(indent(fm), 0);
QPixmap icon = index.data(ChartListModel::IconRole).value<QPixmap>();
if (!icon.isNull()) {
rect.translate(0, topSpace);
painter->drawPixmap(rect.topLeft(), icon);
rect.translate(icon.size().width() + iconSpace, (icon.size().height() - fm.height()) / 2);
}
painter->drawText(rect, name);
}
QSize ChartItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QFont font = index.data(Qt::FontRole).value<QFont>();
QFontMetrics fm(font);
QString name = index.data(ChartListModel::ChartNameRole).value<QString>();
QSize iconSize = index.data(ChartListModel::IconSizeRole).value<QSize>();
QSize size = fm.size(Qt::TextSingleLine, name);
bool isHeader = index.data(ChartListModel::IsHeaderRole).value<bool>();
if (!isHeader)
size += QSize(indent(fm), 0);
if (iconSize.isValid())
size = QSize(size.width() + iconSize.width() + iconSpace,
std::max(size.height(), iconSize.height()) + 2 * topSpace);
return size;
}
static const QUrl urlStatsView = QUrl(QStringLiteral("qrc:/qml/statsview2.qml"));
StatsWidget::StatsWidget(QWidget *parent) : QWidget(parent)
{
ui.setupUi(this);
connect(ui.close, &QToolButton::clicked, this, &StatsWidget::closeStats);
ui.chartType->setModel(&charts);
connect(ui.chartType, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::chartTypeChanged);
connect(ui.var1, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var1Changed);
connect(ui.var2, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var2Changed);
connect(ui.var1Binner, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var1BinnerChanged);
connect(ui.var2Binner, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var2BinnerChanged);
connect(ui.var2Operation, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var2OperationChanged);
connect(ui.var1Sort, QOverload<int>::of(&QComboBox::activated), this, &StatsWidget::var1SortChanged);
connect(ui.restrictButton, &QToolButton::clicked, this, &StatsWidget::restrict);
connect(ui.unrestrictButton, &QToolButton::clicked, this, &StatsWidget::unrestrict);
ui.stats->setSource(urlStatsView);
ui.stats->setResizeMode(QQuickWidget::SizeRootObjectToView);
(void)getView();
}
// hack around the Qt6 bug where the QML object gets destroyed and recreated
StatsView *StatsWidget::getView()
{
StatsView *view = qobject_cast<StatsView *>(ui.stats->rootObject());
if (!view)
qWarning("Oops. The root of the StatsView is not a StatsView.");
if (view) {
// try to prevent the JS garbage collection from freeing the object
// this appears to fail with Qt6 which is why we still look up the
// object from the ui.stats rootObject
ui.stats->engine()->setObjectOwnership(view, QQmlEngine::CppOwnership);
view->setParent(this);
view->setVisible(isVisible()); // Synchronize visibility of widget and QtQuick-view.
}
return view;
}
// Initialize QComboBox with list of variables
static void setVariableList(QComboBox *combo, const StatsState::VariableList &list)
{
combo->clear();
combo->setEnabled(!list.variables.empty());
for (const StatsState::Variable &v: list.variables)
combo->addItem(v.name, QVariant(v.id));
combo->setCurrentIndex(list.selected);
}
// Initialize QComboBox and QLabel of binners. Hide if there are no binners.
static void setBinList(QComboBox *combo, const StatsState::BinnerList &list)
{
combo->clear();
combo->setEnabled(!list.binners.empty());
for (const QString &s: list.binners)
combo->addItem(s);
combo->setCurrentIndex(list.selected);
}
void StatsWidget::updateUi()
{
StatsState::UIState uiState = state.getUIState();
setVariableList(ui.var1, uiState.var1);
setVariableList(ui.var2, uiState.var2);
int pos = charts.update(uiState.charts);
ui.chartType->setCurrentIndex(pos);
ui.chartType->setItemDelegate(new ChartItemDelegate);
setBinList(ui.var1Binner, uiState.binners1);
setBinList(ui.var2Binner, uiState.binners2);
setVariableList(ui.var2Operation, uiState.operations2);
setVariableList(ui.var1Sort, uiState.sortMode1);
ui.sortGroup->setVisible(!uiState.sortMode1.variables.empty());
// Add checkboxes for additional features
features.clear();
for (const StatsState::Feature &f: uiState.features) {
features.emplace_back(new QCheckBox(f.name));
QCheckBox *check = features.back().get();
check->setChecked(f.selected);
int id = f.id;
connect(check, &QCheckBox::stateChanged, [this,id] (int state) { featureChanged(id, state); });
ui.features->addWidget(check);
}
StatsView *view = getView();
if (view)
view->plot(state);
}
void StatsWidget::updateRestrictionLabel()
{
StatsView *view = getView();
if (!view)
return;
int num = view->restrictionCount();
if (num < 0)
ui.restrictionLabel->setText(tr("Analyzing all dives"));
else
ui.restrictionLabel->setText(tr("Analyzing subset (%L1) dives").arg(num));
ui.unrestrictButton->setEnabled(num > 0);
}
void StatsWidget::closeStats()
{
MainWindow::instance()->setApplicationState(MainWindow::ApplicationState::Default);
}
void StatsWidget::chartTypeChanged(int idx)
{
state.chartChanged(ui.chartType->itemData(idx).toInt());
updateUi();
}
void StatsWidget::var1Changed(int idx)
{
state.var1Changed(ui.var1->itemData(idx).toInt());
updateUi();
}
void StatsWidget::var2Changed(int idx)
{
state.var2Changed(ui.var2->itemData(idx).toInt());
updateUi();
}
void StatsWidget::var1BinnerChanged(int idx)
{
state.binner1Changed(idx);
updateUi();
}
void StatsWidget::var2BinnerChanged(int idx)
{
state.binner2Changed(idx);
updateUi();
}
void StatsWidget::var2OperationChanged(int idx)
{
state.var2OperationChanged(ui.var2Operation->itemData(idx).toInt());
updateUi();
}
void StatsWidget::var1SortChanged(int idx)
{
state.sortMode1Changed(ui.var1Sort->itemData(idx).toInt());
updateUi();
}
void StatsWidget::featureChanged(int idx, bool status)
{
state.featureChanged(idx, status);
// No need for a full chart replot - just show/hide the features
StatsView *view = getView();
if (view)
view->updateFeatures(state);
}
void StatsWidget::showEvent(QShowEvent *e)
{
unrestrict();
updateUi();
QWidget::showEvent(e);
// Apparently, we have to manage the visibility of the view ourselves. That's mad.
// this is implicitly done in getView() - so we can ignore the return value
(void)getView();
}
void StatsWidget::hideEvent(QHideEvent *e)
{
QWidget::hideEvent(e);
// Apparently, we have to manage the visibility of the view ourselves. That's mad.
// this is implicitly done in getView() - so we can ignore the return value
(void)getView();
}
void StatsWidget::restrict()
{
StatsView *view = getView();
if (view)
view->restrictToSelection();
updateRestrictionLabel();
}
void StatsWidget::unrestrict()
{
StatsView *view = getView();
if (view)
view->unrestrict();
updateRestrictionLabel();
}