Merge pull request #1559 from DaTweety/feature/folio-crosshair

Folio-wide crosshair under the mouse (Display menu)

sources/diagramview.cpp

@@ -47,6 +47,7 @@
 #include "utils/conductorcreator.h"
 #include "undocommand/addgraphicsobjectcommand.h"
 #include "diagram.h"
+#include <QSettings>
 #include "foliogrid.h"
 #include "diagramcontexttoolbar.h"
 #include "imagedrop.h"
@@ -1040,6 +1041,7 @@ void DiagramView::mouseMoveEvent(QMouseEvent *e)
 {
 	m_last_mouse_pos = e->pos();
 	setToolTip(tr("X: %1 Y: %2").arg(e->pos().x()).arg(e->pos().y()));
+	moveCrosshair(e->pos());
 	if (m_event_interface && m_event_interface->mouseMoveEvent(e)) return;
 
 	if (m_gesture_tracking)
@@ -1840,6 +1842,117 @@ void DiagramView::setCellLinesShown(bool shown)
 	viewport()->update();
 }
 
+namespace {
+		/// The setting, read once and then kept here for every view
+	int s_crosshair = -1;
+}
+
+/**
+	@brief DiagramView::crosshairShown
+	@return true when the folio-wide crosshair follows the mouse: two thin
+	lines across the whole folio, through the grid point under the mouse,
+	to see at a glance whether symbols and terminals are in line. Drawn
+	on screen only, never exported nor printed.
+*/
+bool DiagramView::crosshairShown()
+{
+	if (s_crosshair < 0) {
+		QSettings settings;
+		s_crosshair = settings.value(QStringLiteral("diagrameditor/crosshair"), false).toBool();
+	}
+	return s_crosshair;
+}
+
+/**
+	@brief DiagramView::setCrosshairShown
+	@param shown : show the folio-wide crosshair in every view; kept in
+	the settings. The views repaint themselves at the next mouse move.
+*/
+void DiagramView::setCrosshairShown(bool shown)
+{
+	s_crosshair = shown;
+	QSettings settings;
+	settings.setValue(QStringLiteral("diagrameditor/crosshair"), shown);
+}
+
+/**
+	@brief DiagramView::crosshairArea
+	@return the part of the viewport the two lines through @a scene_pos
+	cover, a little wider than the lines
+*/
+QRect DiagramView::crosshairArea(const QPointF &scene_pos) const
+{
+	const QPoint p = mapFromScene(scene_pos);
+	const QRect all = viewport()->rect();
+	return QRect(all.left(), p.y() - 2, all.width(), 5)
+			| QRect(p.x() - 2, all.top(), 5, all.height());
+}
+
+/**
+	@brief DiagramView::moveCrosshair
+	Follow the mouse with the crosshair, on the grid, repainting only the
+	lines it leaves and the lines it draws.
+	@param viewport_pos : the mouse, in viewport coordinates
+*/
+void DiagramView::moveCrosshair(const QPoint &viewport_pos)
+{
+	if (!crosshairShown()) {
+		hideCrosshair();
+		return;
+	}
+	const QPointF pos = Diagram::snapToGrid(mapToScene(viewport_pos));
+	if (m_crosshair_visible && pos == m_crosshair_pos)
+		return;
+	if (m_crosshair_visible)
+		viewport()->update(crosshairArea(m_crosshair_pos));
+	m_crosshair_pos = pos;
+	m_crosshair_visible = true;
+	viewport()->update(crosshairArea(m_crosshair_pos));
+}
+
+/**
+	@brief DiagramView::hideCrosshair
+	Take the crosshair away, when the mouse leaves the view or the
+	setting is switched off.
+*/
+void DiagramView::hideCrosshair()
+{
+	if (!m_crosshair_visible)
+		return;
+	m_crosshair_visible = false;
+	viewport()->update(crosshairArea(m_crosshair_pos));
+}
+
+/**
+	@brief DiagramView::drawForeground
+	Over everything else, the folio-wide crosshair, inside the folio's
+	border only.
+	@param painter
+	@param rect
+*/
+void DiagramView::drawForeground(QPainter *painter, const QRectF &rect)
+{
+	PaletteGraphicsView::drawForeground(painter, rect);
+	if (!m_crosshair_visible || !crosshairShown() || !m_diagram)
+		return;
+
+	const QRectF area = m_diagram->border_and_titleblock.insideBorderRect();
+	if (!area.contains(m_crosshair_pos))
+		return;
+
+	QPainter *p = scenePainter(painter);
+	p->save();
+	QPen pen(Diagram::background_color == Qt::darkGray ? QColor(Qt::lightGray)
+													   : QColor(0, 120, 215));
+	pen.setCosmetic(true);
+	pen.setWidthF(0);
+	p->setPen(pen);
+	p->setRenderHint(QPainter::Antialiasing, false);
+	p->drawLine(QLineF(area.left(), m_crosshair_pos.y(), area.right(), m_crosshair_pos.y()));
+	p->drawLine(QLineF(m_crosshair_pos.x(), area.top(), m_crosshair_pos.x(), area.bottom()));
+	p->restore();
+}
+
 /**
 	@brief DiagramView::drawBackground
 	Reimplemented from PaletteGraphicsView: over the folio background, the
@@ -1976,6 +2089,9 @@ bool DiagramView::viewportEvent(QEvent *event)
 	if (event->type() == QEvent::Resize) {
 		placeCellRulers();
 	}
+	if (event->type() == QEvent::Leave) {
+		hideCrosshair();
+	}
 	return PaletteGraphicsView::viewportEvent(event);
 }
 

sources/diagramview.h

@@ -74,6 +74,11 @@ class DiagramView : public PaletteGraphicsView
 		QPoint            m_gesture_origin;
 		DiagramGestureOverlay *m_gesture_overlay = nullptr;
 		QPoint            m_last_mouse_pos = QPoint(-1, -1);
+		QPointF           m_crosshair_pos;
+		bool              m_crosshair_visible = false;
+		void moveCrosshair(const QPoint &viewport_pos);
+		void hideCrosshair();
+		QRect crosshairArea(const QPointF &scene_pos) const;
 		QPointF           m_drag_last_pos;
 		bool              m_fresh_focus_in,
 						  m_first_activation = true;
@@ -111,6 +116,12 @@ class DiagramView : public PaletteGraphicsView
 		QPointF defaultPlacementPos() const;
 		void setCellRulersShown(bool shown);
 		void setCellLinesShown(bool shown);
+			/// The folio-wide crosshair under the mouse (Display menu),
+			/// one setting for every view
+		static bool crosshairShown();
+		static void setCrosshairShown(bool shown);
+		bool crosshairVisible() const { return m_crosshair_visible; }
+		QPointF crosshairPos() const { return m_crosshair_pos; }
 
 	protected:
 		void mouseDoubleClickEvent(QMouseEvent *) override;
@@ -127,6 +138,7 @@ class DiagramView : public PaletteGraphicsView
 		void paintEvent(QPaintEvent *event) override;
 		bool viewportEvent(QEvent *event) override;
 		void drawBackground(QPainter *painter, const QRectF &rect) override;
+		void drawForeground(QPainter *painter, const QRectF &rect) override;
 		void paintingInverted(bool inverted) override;
 		void mousePressEvent(QMouseEvent *) override;
 		void mouseMoveEvent(QMouseEvent *) override;

sources/qetdiagrameditor.cpp

@@ -590,6 +590,19 @@ void QETDiagramEditor::setUpActions()
 			}
 	});
 
+		//A crosshair across the whole folio under the mouse, to see
+		//whether symbols and terminals are in line
+	m_crosshair = new QAction(tr("Folio-wide crosshair"), this);
+	ShortcutManager::instance().registerAction(m_crosshair, "diagrameditor.crosshair", tr("Diagram editors"), QKeySequence());
+	m_crosshair->setStatusTip(tr("Show two lines across the whole folio under the mouse, to see whether parts are in line"));
+	m_crosshair->setCheckable(true);
+	m_crosshair->setChecked(DiagramView::crosshairShown());
+	connect(m_crosshair, &QAction::triggered, [this](bool checked) {
+		DiagramView::setCrosshairShown(checked);
+		for (DiagramView *view : findChildren<DiagramView *>())
+			view->viewport()->update();
+	});
+
 		//Snap step for dragged texts, as a fraction of the folio grid
 	m_text_grid_menu = new QMenu(tr("Text grid"), this);
 	m_text_grid_menu->setIcon(QET::Icons::Grid);
@@ -1703,6 +1716,7 @@ void QETDiagramEditor::setUpMenu()
 	menu_affichage -> addAction(m_mode_visualise);
 	menu_affichage -> addSeparator();
 	menu_affichage -> addAction(m_draw_grid);
+	menu_affichage -> addAction(m_crosshair);
 	menu_affichage -> addMenu(m_text_grid_menu);
 	menu_affichage -> addAction(m_draw_guides);
 	menu_affichage -> addAction(m_cell_rulers);

sources/qetdiagrameditor.h

@@ -264,6 +264,7 @@ class QETDiagramEditor : public QETMainWindow
 		*m_configure_duplicate,		///< Reopen the duplicate offset/direction dialog (#991)
 		*m_auto_conductor,		///< Enable/Disable the use of auto conductor
 		*m_auto_break_conductor,	///< Enable/Disable the use of auto break conductor
+		*m_crosshair,			///< Show the folio-wide crosshair
 		*m_add_cable = nullptr,		///< Draw the trunk line of a cable
 		*m_draw_grid,			///< Switch the background grid display or not
 		*m_draw_guides = nullptr,	///< Switch the custom guides display or not