Merge pull request #1038 from ispyisail/feature/cell-rulers

Add an option to keep the folio row and column headers visible (#1034)

sources/diagramview.cpp

@@ -16,6 +16,7 @@
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include "diagramview.h"
+#include "cellruler.h"
 #include "lastusedstyle.h"
 #include "qetproject.h"
 #include "QPropertyUndoCommand/qpropertyundocommand.h"
@@ -108,6 +109,13 @@ DiagramView::DiagramView(Diagram *diagram, QWidget *parent) :
 	connect(&(m_diagram -> border_and_titleblock), &BorderTitleBlock::informationChanged, this, &DiagramView::updateWindowTitle);
 	connect(diagram, &Diagram::findElementRequired, this, &DiagramView::findElementRequired);
 
+	m_top_ruler = new CellRuler(Qt::Horizontal, this);
+	m_side_ruler = new CellRuler(Qt::Vertical, this);
+	m_cell_rulers_shown = QSettings().value("diagrameditor/cell_rulers", false).toBool();
+	connect(&m_diagram->border_and_titleblock, &BorderTitleBlock::borderChanged, this, &DiagramView::updateCellRulers);
+	connect(&m_diagram->border_and_titleblock, &BorderTitleBlock::displayChanged, this, &DiagramView::updateCellRulers);
+	updateCellRulers();
+
 	QShortcut *edit_conductor_color_shortcut = new QShortcut(QKeySequence(Qt::Key_F2), this);
 	connect(edit_conductor_color_shortcut, &QShortcut::activated, [this]()
 	{
@@ -1188,6 +1196,82 @@ void DiagramView::paintingInverted(bool inverted)
 	m_diagram->setInvertedLightness(inverted);
 }
 
+/**
+	@brief DiagramView::setCellRulersShown
+	Show or hide the rulers that keep the column numbers and the row
+	letters of the folio border in sight along the edges of this view.
+	@param shown
+*/
+void DiagramView::setCellRulersShown(bool shown)
+{
+	m_cell_rulers_shown = shown;
+	updateCellRulers();
+}
+
+/**
+	@brief DiagramView::updateCellRulers
+	Show each ruler when the rulers are wanted and the folio shows the
+	matching header, and give it room in the margins of the view. The
+	part of the folio in sight stays in sight when the viewport resizes.
+*/
+void DiagramView::updateCellRulers()
+{
+	const BorderTitleBlock &border = m_diagram->border_and_titleblock;
+	const bool top = m_cell_rulers_shown
+			 && border.borderIsDisplayed() && border.columnsAreDisplayed();
+	const bool side = m_cell_rulers_shown
+			  && border.borderIsDisplayed() && border.rowsAreDisplayed();
+	const int thickness = m_top_ruler->thickness();
+
+	m_top_ruler->setVisible(top);
+	m_side_ruler->setVisible(side);
+	m_side_ruler->setLeadingSpace(top ? thickness : 0);
+
+	const QMargins margins(side ? thickness : 0, top ? thickness : 0, 0, 0);
+	if (margins != viewportMargins()) {
+		const QPointF centre = mapToScene(viewport()->rect().center());
+		setViewportMargins(margins);
+		centerOn(centre);
+	}
+	placeCellRulers();
+	m_top_ruler->update();
+	m_side_ruler->update();
+}
+
+/**
+	@brief DiagramView::placeCellRulers
+	Lay the rulers along the top and the left edges of the viewport, the
+	side ruler covering the corner too when both are shown.
+*/
+void DiagramView::placeCellRulers()
+{
+	if (!m_top_ruler) {
+		return;
+	}
+	const QRect viewport_rect = viewport()->geometry();
+	const int thickness = m_top_ruler->thickness();
+	const int corner = m_top_ruler->isHidden() ? 0 : thickness;
+	m_top_ruler->setGeometry(viewport_rect.left(), viewport_rect.top() - thickness,
+				 viewport_rect.width(), thickness);
+	m_side_ruler->setGeometry(viewport_rect.left() - thickness, viewport_rect.top() - corner,
+				  thickness, viewport_rect.height() + corner);
+}
+
+/**
+	@brief DiagramView::viewportEvent
+	Keep the rulers along the viewport when it resizes, which it also does
+	without the view resizing, when the scroll bars come and go.
+	@param event
+	@return what QGraphicsView::viewportEvent() returns
+*/
+bool DiagramView::viewportEvent(QEvent *event)
+{
+	if (event->type() == QEvent::Resize) {
+		placeCellRulers();
+	}
+	return PaletteGraphicsView::viewportEvent(event);
+}
+
 /**
 	@brief DiagramView::paintEvent
 	Reimplemented from QGraphicsView
@@ -1197,6 +1281,13 @@ void DiagramView::paintEvent(QPaintEvent *event)
 {
 	PaletteGraphicsView::paintEvent(event);
 
+		//Scrolling and zooming both repaint the viewport: follow them
+	if (viewportTransform() != m_rulers_transform) {
+		m_rulers_transform = viewportTransform();
+		m_top_ruler->update();
+		m_side_ruler->update();
+	}
+
 	if (m_free_rubberbanding && m_free_rubberband.count() >= 3)
 	{
 		QPainter painter(viewport());