Merge pull request #1603 from DaTweety/feature/grid-zoom

Grid hidden when its dots crowd, at a distance you set; zoom in the status bar

lang/qet_nl_NL.ts

@@ -6377,6 +6377,21 @@ Any setting other than “No rounding” may cause rendering errors in the proje
 3 - editing the project on another computer and/or screen that does not have the same settings as in points 1 and 2.</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <location filename="../sources/ui/configpage/generalconfigurationpage.ui" line="162"/>
+        <source>Hide the grid when its dots are closer on screen than</source>
+        <translation>Raster verbergen als de punten op het scherm dichter bij elkaar staan dan</translation>
+    </message>
+    <message>
+        <location filename="../sources/ui/configpage/generalconfigurationpage.ui" line="172"/>
+        <source>Zoomed out further, the dots of any grid step are left out; the zoom shown in the status bar tells where</source>
+        <translation>Verder uitgezoomd vallen de punten van elke rasterstap weg; de zoom in de statusbalk toont waar</translation>
+    </message>
+    <message>
+        <location filename="../sources/ui/configpage/generalconfigurationpage.ui" line="175"/>
+        <source> px</source>
+        <translation> px</translation>
+    </message>
 </context>
 <context>
     <name>GenericPanel</name>
@@ -11807,6 +11822,16 @@ Unbridge and/or remove the levels from the affected terminals so that they can b
         <comment>message box title</comment>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <location filename="../sources/qetdiagrameditor.cpp" line="4285"/>
+        <source>Zoom %1 %</source>
+        <translation>Zoom %1 %</translation>
+    </message>
+    <message>
+        <location filename="../sources/qetdiagrameditor.cpp" line="811"/>
+        <source>Zoom of the folio on screen</source>
+        <translation>Zoom van het blad op het scherm</translation>
+    </message>
     <message>
         <location filename="../sources/qetdiagrameditor.cpp" line="702"/>
         <source>Snap to the grid</source>

sources/diagram.cpp

@@ -351,42 +351,46 @@ void Diagram::drawBackground(QPainter *p, const QRectF &r) {
 		const int xGrid = FolioGrid::step(settings.value(FolioGrid::x_key), Diagram::xGrid);
 		const int yGrid = FolioGrid::step(settings.value(FolioGrid::y_key), Diagram::yGrid);
 
-		qreal limit_x = rect.x() + rect.width();
-		qreal limit_y = rect.y() + rect.height();
+			//Left out when they would crowd, whatever the grid step
+		const qreal zoom_factor = p->transform().m11();
+		if (FolioGrid::dotsShown(xGrid, yGrid, zoom_factor,
+					 FolioGrid::minDotSpacing(settings.value(FolioGrid::min_dot_spacing_key))))
+		{
+			qreal limit_x = rect.x() + rect.width();
+			qreal limit_y = rect.y() + rect.height();
 
-		int g_x = (int)ceil(rect.x());
-		while (g_x % xGrid) ++ g_x;
-		int g_y = (int)ceil(rect.y());
-		while (g_y % yGrid) ++ g_y;
+			int g_x = (int)ceil(rect.x());
+			while (g_x % xGrid) ++ g_x;
+			int g_y = (int)ceil(rect.y());
+			while (g_y % yGrid) ++ g_y;
 
-		QPolygon points;
-		for (int gx = g_x ; gx < limit_x ; gx += xGrid) {
-			for (int gy = g_y ; gy < limit_y ; gy += yGrid) {
-				points << QPoint(gx, gy);
-			}
-		}
-
-		qreal zoom_factor = p->transform().m11();
-		int minWidthPen = settings.value(QStringLiteral("diagrameditor/grid_pointsize_min"), 1).toInt();
-		int maxWidthPen = settings.value(QStringLiteral("diagrameditor/grid_pointsize_max"), 1).toInt();
-		pen.setWidth(minWidthPen);
-		if (minWidthPen != maxWidthPen) {
-			qreal stepPen  = (maxWidthPen - minWidthPen) / (qreal)maxWidthPen;
-			qreal stepZoom = (5.0 - 1.0) / maxWidthPen;
-			for (int n=0; n<maxWidthPen; n++) {
-				if ((zoom_factor > (1.0 + n * stepZoom)) && (zoom_factor <= (1.0 + (n+1) * stepZoom))) {
-					int widthPen = minWidthPen + qRound(n * stepPen);
-					pen.setWidth(widthPen);
+			QPolygon points;
+			for (int gx = g_x ; gx < limit_x ; gx += xGrid) {
+				for (int gy = g_y ; gy < limit_y ; gy += yGrid) {
+					points << QPoint(gx, gy);
 				}
 			}
-			if		(zoom_factor <= 1.0)
-						pen.setWidth(minWidthPen);
-			else if (zoom_factor > (1.0 + stepZoom * maxWidthPen))
-						pen.setWidth(maxWidthPen);
+
+			int minWidthPen = settings.value(QStringLiteral("diagrameditor/grid_pointsize_min"), 1).toInt();
+			int maxWidthPen = settings.value(QStringLiteral("diagrameditor/grid_pointsize_max"), 1).toInt();
+			pen.setWidth(minWidthPen);
+			if (minWidthPen != maxWidthPen) {
+				qreal stepPen  = (maxWidthPen - minWidthPen) / (qreal)maxWidthPen;
+				qreal stepZoom = (5.0 - 1.0) / maxWidthPen;
+				for (int n=0; n<maxWidthPen; n++) {
+					if ((zoom_factor > (1.0 + n * stepZoom)) && (zoom_factor <= (1.0 + (n+1) * stepZoom))) {
+						int widthPen = minWidthPen + qRound(n * stepPen);
+						pen.setWidth(widthPen);
+					}
+				}
+				if		(zoom_factor <= 1.0)
+							pen.setWidth(minWidthPen);
+				else if (zoom_factor > (1.0 + stepZoom * maxWidthPen))
+							pen.setWidth(maxWidthPen);
+			}
+			p -> setPen(pen);
+			p -> drawPoints(points);
 		}
-		p -> setPen(pen);
-		if (zoom_factor > 0.5) // no grid below ... !
-				p -> drawPoints(points);
 	}
 
 	if (draw_guides_) {

sources/diagramview.cpp

@@ -2337,6 +2337,12 @@ void DiagramView::paintEvent(QPaintEvent *event)
 {
 	PaletteGraphicsView::paintEvent(event);
 
+		//Every way of zooming ends in a repaint
+	if (transform().m11() != m_shown_zoom) {
+		m_shown_zoom = transform().m11();
+		emit zoomChanged(m_shown_zoom);
+	}
+
 		//Scrolling and zooming both repaint the viewport: follow them.
 		//Showing or hiding a ruler resizes the viewport, which cannot be
 		//done while it paints.

sources/diagramview.h

@@ -113,6 +113,7 @@ class DiagramView : public PaletteGraphicsView
 		bool m_cell_rulers_shown = false;
 		/// Last viewport transform the rulers were painted for
 		QTransform m_rulers_transform;
+		qreal m_shown_zoom = 0;
 		bool m_cell_lines_shown = false;
 
 		
@@ -229,6 +230,8 @@ class DiagramView : public PaletteGraphicsView
 			/// Signal emitted when the placement mode is entered for an
 			/// element (not a macro), whether from a drop or not.
 		void elementPlacementStarted(const ElementsLocation &);
+			/// The view's scale changed: 1 is 100 %
+		void zoomChanged(qreal factor);
 	
 	public slots:
 		void setVisualisationMode();

sources/foliogrid.h

@@ -19,7 +19,9 @@
 #define FOLIOGRID_H
 
 #include <QString>
+#include <QtGlobal>
 #include <QVariant>
+#include <cmath>
 #include <limits>
 
 /**
@@ -49,6 +51,46 @@ namespace FolioGrid
 			return fallback;
 		return int(s);
 	}
+
+		/// QSettings key of the smallest distance, in pixels on screen,
+		/// at which grid dots are still drawn (General > Appearance)
+	inline const QString min_dot_spacing_key{QStringLiteral("diagrameditor/grid_min_dot_spacing")};
+		/// Grid dots closer than this on screen, in pixels, read as a
+		/// gray haze rather than as a grid. With the default step of 10,
+		/// the dots go below a zoom of 75 %.
+	constexpr double default_min_dot_spacing = 7.5;
+		/// The smallest and largest distance the preferences page offers
+	constexpr double min_dot_spacing_lowest = 1.0;
+	constexpr double min_dot_spacing_highest = 50.0;
+
+	/**
+		@return the smallest dot distance held in @p value, a settings
+		entry, or the default when it is missing, not a number, not
+		finite, or outside what the preferences page offers: a hand-edited
+		"inf" or 1e9 would hide the grid for good while the page showed
+		another value.
+	*/
+	inline double minDotSpacing(const QVariant &value)
+	{
+		bool ok = false;
+		const double spacing = value.toDouble(&ok);
+		return ok && std::isfinite(spacing)
+				&& spacing >= min_dot_spacing_lowest && spacing <= min_dot_spacing_highest
+				? spacing : default_min_dot_spacing;
+	}
+
+	/**
+		@return true when the grid dots are drawn: when two of them, @p x_step
+		and @p y_step apart on the folio, stand at least @p min_spacing
+		pixels apart on screen at @p zoom (1 is 100 %). Whatever the step,
+		they go when they would crowd; with the default step of 10 and
+		spacing of 7.5, below a zoom of 75 %.
+	*/
+	inline bool dotsShown(int x_step, int y_step, double zoom,
+			      double min_spacing = default_min_dot_spacing)
+	{
+		return qMin(x_step, y_step) * zoom >= min_spacing;
+	}
 }
 
 #endif // FOLIOGRID_H

sources/qetdiagrameditor.cpp

@@ -838,6 +838,9 @@ void QETDiagramEditor::setUpActions()
 	m_hidden_kinds_label = new QLabel(this);
 	m_hidden_kinds_label->setToolTip(tr("See Display > Show"));
 	statusBar()->addPermanentWidget(m_hidden_kinds_label);
+	m_zoom_label = new QLabel(this);
+	m_zoom_label->setToolTip(tr("Zoom of the folio on screen"));
+	statusBar()->addPermanentWidget(m_zoom_label);
 	connect(QETApp::instance(), &QETApp::shownKindsChanged,
 			this, &QETDiagramEditor::updateShownKinds);
 	updateShownKinds();
@@ -3184,6 +3187,7 @@ void QETDiagramEditor::slot_updateActions()
 	bool opened_project = pv;
 	bool opened_diagram = dv;
 	bool editable_project = (pv && !pv -> project() -> isReadOnly());
+	updateZoomLabel();
 
 	m_close_file->                  setEnabled(opened_project);
 	m_save_file->                   setEnabled(opened_project);
@@ -4273,6 +4277,24 @@ void QETDiagramEditor::diagramWasAdded(DiagramView *dv)
 		&QETDiagramEditor::slot_updateComplexActions);
 	connect(dv, &DiagramView::modeChanged, this, &QETDiagramEditor::slot_updateModeActions);
 	connect(dv, &DiagramView::elementPlacementStarted, this, &QETDiagramEditor::rememberPlacedElement);
+	connect(dv, &DiagramView::zoomChanged, this, &QETDiagramEditor::updateZoomLabel);
+}
+
+/**
+	@brief QETDiagramEditor::updateZoomLabel
+	Show the zoom of the folio on screen in the status bar, nothing when
+	no folio is shown.
+*/
+void QETDiagramEditor::updateZoomLabel()
+{
+	if (!m_zoom_label)
+		return;
+	DiagramView *dv = currentDiagramView();
+		//Four digits, not rounded to a whole percent: the grid's cutoff
+		//(Settings > General) compares the exact zoom, so 77.6 % shows as
+		//such, not as 78 %
+	m_zoom_label->setText(dv ? tr("Zoom %1 %").arg(QLocale().toString(dv->transform().m11() * 100, 'g', 4))
+				 : QString());
 }
 
 /**

sources/qetdiagrameditor.h

@@ -148,6 +148,7 @@ class QETDiagramEditor : public QETMainWindow
 		void alignGroupTriggered     (QAction *action);
 		void rowColumnGroupTriggered (QAction *action);
 		void slot_updateActions();
+		void updateZoomLabel();
 		void slot_updateUndoStack();
 		void slot_updateModeActions();
 		void slot_updateComplexActions();
@@ -330,6 +331,7 @@ class QETDiagramEditor : public QETMainWindow
 		QToolButton *m_text_grid_button = nullptr;
 		QMenu *m_shown_kinds_menu = nullptr;		///< View > Show, kinds of items (#301)
 		QLabel *m_hidden_kinds_label = nullptr;	///< Status bar: how many kinds are hidden
+		QLabel *m_zoom_label = nullptr;		///< Status bar: the zoom of the folio on screen
 
 		QList <QAction *> m_zoom_action_toolBar; ///Only zoom action must displayed in the toolbar
 

sources/ui/configpage/generalconfigurationpage.cpp

@@ -29,6 +29,7 @@
 #include "../../utils/qetutils.h"
 #include "../../utils/previousversions.h"
 #include "../../qetmessagebox.h"
+#include "../../foliogrid.h"
 #include "../../textgrid.h"
 #include "../../wiringrules.h"
 #include "../wiringruleswarning.h"
@@ -110,6 +111,10 @@ GeneralConfigurationPage::GeneralConfigurationPage(QWidget *parent) :
 	}
 
 	ui->grid_startup_cb->setChecked(settings.value("diagrameditor/grid_display_startup", true).toBool());
+	ui->m_grid_min_spacing_sb->setRange(FolioGrid::min_dot_spacing_lowest,
+					      FolioGrid::min_dot_spacing_highest);
+	ui->m_grid_min_spacing_sb->setValue(
+				FolioGrid::minDotSpacing(settings.value(FolioGrid::min_dot_spacing_key)));
 	ui->guides_startup_cb->setChecked(settings.value("diagrameditor/guides_display_startup", false).toBool());
 		//Stored as "inserts" but presented as "edits", so the default (insert)
 		//is the unchecked state -- a preference reads better as an opt-out.
@@ -425,6 +430,7 @@ void GeneralConfigurationPage::applyConf()
 	PreviousVersions::setCount(ui->m_previous_versions_sb->value());
 
 	settings.setValue("diagrameditor/grid_display_startup", ui->grid_startup_cb->isChecked());
+	settings.setValue(FolioGrid::min_dot_spacing_key, ui->m_grid_min_spacing_sb->value());
 	settings.setValue("diagrameditor/guides_display_startup", ui->guides_startup_cb->isChecked());
 	settings.setValue("elementscollection/double-click-inserts", !ui->m_collection_dblclick_edits->isChecked());
 	settings.setValue("elementscollection/search-flat-list", ui->m_collection_search_flat_cb->isChecked());

sources/ui/configpage/generalconfigurationpage.ui

@@ -154,6 +154,58 @@
          </property>
         </widget>
        </item>
+       <item>
+        <layout class="QHBoxLayout" name="m_grid_min_spacing_layout">
+         <item>
+          <widget class="QLabel" name="m_grid_min_spacing_label">
+           <property name="text">
+            <string>Hide the grid when its dots are closer on screen than</string>
+           </property>
+           <property name="buddy">
+            <cstring>m_grid_min_spacing_sb</cstring>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QDoubleSpinBox" name="m_grid_min_spacing_sb">
+           <property name="toolTip">
+            <string>Zoomed out further, the dots of any grid step are left out; the zoom shown in the status bar tells where. In pixels as the system scales them, so the same value suits a HiDPI screen</string>
+           </property>
+           <property name="suffix">
+            <string> px</string>
+           </property>
+           <property name="decimals">
+            <number>1</number>
+           </property>
+           <property name="minimum">
+            <double>1.000000000000000</double>
+           </property>
+           <property name="maximum">
+            <double>50.000000000000000</double>
+           </property>
+           <property name="singleStep">
+            <double>0.500000000000000</double>
+           </property>
+           <property name="value">
+            <double>7.500000000000000</double>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <spacer name="m_grid_min_spacing_spacer">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>40</width>
+             <height>20</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+        </layout>
+       </item>
        <item>
         <widget class="QCheckBox" name="m_collection_dblclick_edits">
          <property name="toolTip">

tests/qttest/tst_foliogrid.cpp

@@ -32,6 +32,41 @@ class tst_foliogrid : public QObject
 	Q_OBJECT
 
 private slots:
+	void dotsGoWhenTheyCrowd()
+	{
+			//The default step and spacing: the dots go below 75 %
+		QVERIFY(FolioGrid::dotsShown(10, 10, 0.75));
+		QVERIFY(!FolioGrid::dotsShown(10, 10, 0.74));
+			//A finer step goes sooner, a coarser one later; the finer of
+			//the two directions decides
+		QVERIFY(!FolioGrid::dotsShown(5, 5, 1.4));
+		QVERIFY(FolioGrid::dotsShown(20, 20, 0.4));
+		QVERIFY(!FolioGrid::dotsShown(20, 5, 1.0));
+			//A spacing set in the settings: 7.8 px keeps them down to 78 %
+		QVERIFY(FolioGrid::dotsShown(10, 10, 0.78, 7.8));
+		QVERIFY(!FolioGrid::dotsShown(10, 10, 0.77, 7.8));
+	}
+
+	void dotSpacingFromSettings()
+	{
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant()), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(7.8)), 7.8);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(QStringLiteral("12"))), 12.0);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(0)), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(-3)), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(QStringLiteral("ten"))), 7.5);
+			//Only what the preferences page offers, 1 to 50 px: no
+			//endless or huge value hides the grid for good
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(1.0)), 1.0);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(50.0)), 50.0);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(0.5)), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(50.5)), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(1e9)), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(QStringLiteral("inf"))), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(std::numeric_limits<double>::infinity())), 7.5);
+		QCOMPARE(FolioGrid::minDotSpacing(QVariant(std::numeric_limits<double>::quiet_NaN())), 7.5);
+	}
+
 	void usableValuesAreKept_data()
 	{
 		QTest::addColumn<QVariant>("value");