statistics: implement a statistics widget on desktop

Implement a widget that shows the statistics state as comboboxes
and the statistics chart. Calls into the statistics code if any
of the comboboxes changes.

The hardest part here is the formatting of the charts list with
its icons and with headings. Sadly, it is not trivial to arrange
icons horizontally. Therefore we would have to fully reimplement
the ComboBox view, which is probably not fun.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

1 files changed, 208 insertions, 0 deletions

diff --git a/desktop-widgets/statswidget.cpp b/desktop-widgets/statswidget.cpp
new file mode 100644
index 000000000..874a6db15
--- /dev/null
+++ b/desktop-widgets/statswidget.cpp
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "statswidget.h"
+#include "mainwindow.h"
+#include "stats/statsview.h"
+#include <QCheckBox>
+#include <QPainter>
+#include <QStyledItemDelegate>
+
+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;
+}
+
+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);
+}
+
+// Initialize QComboBox with list of variables
+static void setVariableList(QComboBox *combo, const StatsState::VariableList &list)
+{
+	combo->clear();
+	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(QLabel *label, QComboBox *combo, const QString &varName, const StatsState::BinnerList &list)
+{
+	combo->clear();
+	if (list.binners.empty()) {
+		label->hide();
+		combo->hide();
+		return;
+	}
+
+	label->show();
+	combo->show();
+
+	for (const QString &s: list.binners)
+		combo->addItem(s);
+	combo->setCurrentIndex(list.selected);
+}
+
+// Initialize QComboBox and QLabel of operations. Hide if there are no operations.
+static void setOperationList(QLabel *label, QComboBox *combo, const QString &varName, const StatsState::VariableList &list)
+{
+	combo->clear();
+	if (list.variables.empty()) {
+		label->hide();
+		combo->hide();
+		return;
+	}
+
+	label->show();
+	combo->show();
+
+	setVariableList(combo, list);
+}
+
+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.var1BinnerLabel, ui.var1Binner, uiState.var1Name, uiState.binners1);
+	setBinList(ui.var2BinnerLabel, ui.var2Binner, uiState.var2Name, uiState.binners2);
+	setOperationList(ui.var2OperationLabel, ui.var2Operation, uiState.var2Name, uiState.operations2);
+
+	// 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);
+	}
+
+	ui.stats->plot(state);
+}
+
+void StatsWidget::closeStats()
+{
+	MainWindow::instance()->setApplicationState(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::featureChanged(int idx, bool status)
+{
+	state.featureChanged(idx, status);
+	updateUi();
+}
+
+void StatsWidget::showEvent(QShowEvent *e)
+{
+	updateUi();
+	QWidget::showEvent(e);
+}