Show grid

4 files changed, 115 insertions, 1 deletions

diff --git a/src/diagramdocument.cpp b/src/diagramdocument.cpp
index 71b38db..7ed2418 100644
--- a/src/diagramdocument.cpp
+++ b/src/diagramdocument.cpp
@@ -14,6 +14,7 @@
 // with this program; if not, write to the Free Software Foundation, Inc.,
 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
+#include <cmath>
 #include "diagramdocument.h"
 #include "diagramobject.h"
 #include "diagramconnection.h"
@@ -25,13 +26,88 @@
 #include <QDebug>
 #include <QFile>
 #include <QTextStream>
+#include <QStyle>
+
+using namespace std;
+
+class DiagramDocument::DiagramDocumentPrivate
+{
+public:
+	DiagramDocumentPrivate() :
+		gridSize(10),
+		gridVisible(true),
+		gridPen(QColor(185, 185, 185), 0)
+		{}
+	int gridSize;
+	bool gridVisible;
+	QPen gridPen;
+};
 
 DiagramDocument::DiagramDocument(QObject *parent)
-	: QGraphicsScene(parent), m_mode(DiagramDocument::Select), m_line(NULL)
+	: QGraphicsScene(parent), d(new DiagramDocumentPrivate), m_mode(DiagramDocument::Select), m_line(NULL)
 {
 	m_undoStack = new QUndoStack(this);
 }
 
+int
+DiagramDocument::gridSize() const
+{
+	return d->gridSize;
+}
+
+void
+DiagramDocument::setGridSize(int size)
+{
+	d->gridSize = size;
+	update();
+}
+
+bool
+DiagramDocument::isGridVisible() const
+{
+	return d->gridVisible;
+}
+
+void
+DiagramDocument::setGridVisible(bool visible)
+{
+	d->gridVisible = visible;
+	update();
+}
+
+QColor
+DiagramDocument::gridColor() const
+{
+	return d->gridPen.color();
+}
+
+void
+DiagramDocument::setGridColor(const QColor &color)
+{
+	d->gridPen.setColor(color);
+	update();
+}
+
+void
+DiagramDocument::drawBackground(QPainter *painter, const QRectF &rect)
+{
+	if (d->gridVisible) {
+		qreal gridSize = d->gridSize;
+		qreal x0 = gridSize * floor(rect.left() / gridSize);
+		qreal y0 = gridSize * floor(rect.top() / gridSize);
+		qreal x1 = gridSize * ceil(rect.right() / gridSize);
+		qreal y1 = gridSize * ceil(rect.bottom() / gridSize);
+		painter->save();
+		painter->setPen(d->gridPen);
+		painter->setRenderHint(QPainter::Antialiasing, false);
+		// FIXME do this in one QPainter::drawPoints call
+		for (qreal x = x0; x < x1; x += gridSize)
+			for (qreal y = y0; y < y1; y += gridSize)
+				painter->drawPoint(x, y);
+		painter->restore();
+	}
+}
+
 DiagramDocument::Mode
 DiagramDocument::mode()
 {
diff --git a/src/diagramdocument.h b/src/diagramdocument.h
index 747508b..a02ef09 100644
--- a/src/diagramdocument.h
+++ b/src/diagramdocument.h
@@ -34,6 +34,9 @@ class DiagramObject;
 class DiagramDocument : public QGraphicsScene
 {
 	Q_OBJECT
+	Q_PROPERTY(int gridSize READ gridSize WRITE setGridSize)
+	Q_PROPERTY(bool gridVisible READ isGridVisible WRITE setGridVisible)
+	Q_PROPERTY(QColor gridColor READ gridColor WRITE setGridColor)
 
 public:
 	DiagramDocument(QObject *parent = 0);
@@ -66,6 +69,15 @@ public:
 	QList<DiagramConnection *> findConnections(DiagramObject *object);
 	template <class T> QList<T *> itemsByType();
 
+	int gridSize() const;
+	void setGridSize(int size);
+
+	bool isGridVisible() const;
+	void setGridVisible(bool visible);
+
+	QColor gridColor() const;
+	void setGridColor(const QColor &color);
+
 signals:
 	void modeChanged(DiagramDocument::Mode mode);
 
@@ -79,7 +91,12 @@ protected:
 	void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
 	void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
 
+	void drawBackground(QPainter *painter, const QRectF &rect);
+
 private:
+	class DiagramDocumentPrivate;
+	DiagramDocumentPrivate *const d;
+
 	bool m_trackingMoves;
 	QMap<DiagramItem *, QPointF> m_movedItems;
 
diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index f714ad2..867bdbf 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -253,6 +253,18 @@ MainWindow::setupActions()
 	m_actionQuit->setIcon(IconProvider::findIcon(16, "application-exit.png"));
 	m_actionQuit->setShortcut(QKeySequence(tr("Ctrl+Q")));
 	connect(m_actionQuit, SIGNAL(triggered(bool)), SLOT(closeAll()));
+
+	m_actionShowGrid = new QAction(this);
+	m_actionShowGrid->setText(tr("Show &Grid"));
+	m_actionShowGrid->setCheckable(true);
+	connect(m_actionShowGrid, SIGNAL(triggered(bool)), SLOT(showGrid(bool)));
+}
+
+void
+MainWindow::showGrid(bool checked)
+{
+	m_model->undoStack()->push(
+		new SetObjectPropertyCommand(m_model, "gridVisible", checked));
 }
 
 void
@@ -334,6 +346,9 @@ MainWindow::setupMenuBar()
 	menu->addSeparator();
 	menu->addAction(m_actionDelete);
 
+	QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
+	viewMenu->addAction(m_actionShowGrid);
+
 	menu = menuBar()->addMenu(tr("&Help"));
 	menu->addAction(m_actionAbout);
 }
@@ -461,6 +476,8 @@ MainWindow::newModel(DiagramDocument *newModel)
 	m_undoGroup->addStack(m_model->undoStack());
 	m_undoGroup->setActiveStack(m_model->undoStack());
 
+	m_actionShowGrid->setChecked(m_model->isGridVisible());
+
 	connect(m_model,
 		SIGNAL(modeChanged(DiagramDocument::Mode)),
 		SLOT(updateMode(DiagramDocument::Mode)));
diff --git a/src/mainwindow.h b/src/mainwindow.h
index d5c3ba3..cc52934 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -71,6 +71,8 @@ public slots:
 	void updateClipboard(QClipboard::Mode mode);
 	void closeAll();
 
+	void showGrid(bool);
+
 protected:
 	void setupUi();
 	void setupActions();
@@ -103,6 +105,8 @@ private:
 	QAction *m_actionClose;
 	QAction *m_actionQuit;
 
+	QAction *m_actionShowGrid;
+
 	QAction *m_actionCut;
 	QAction *m_actionCopy;
 	QAction *m_actionPaste;