Refine QgsLayoutGuide API

Author: nyalldawson

python/core/layout/qgslayoutguidecollection.sip

@@ -8,7 +8,7 @@
 
 
 
-class QgsLayoutGuide
+class QgsLayoutGuide : QObject
 {
 %Docstring
  Contains the configuration for a single snap guide used by a layout.

src/core/layout/qgslayoutguidecollection.cpp

@@ -24,7 +24,8 @@
 //
 
 QgsLayoutGuide::QgsLayoutGuide( QgsLayout *layout, Orientation orientation, const QgsLayoutMeasurement &position )
-  : mOrientation( orientation )
+  : QObject( layout )
+  , mOrientation( orientation )
   , mPosition( position )
   , mLayout( layout )
   , mLineItem( new QGraphicsLineItem() )
@@ -50,6 +51,7 @@ void QgsLayoutGuide::setPosition( const QgsLayoutMeasurement &position )
 {
   mPosition = position;
   update();
+  emit positionChanged();
 }
 
 int QgsLayoutGuide::page() const
@@ -110,6 +112,19 @@ QGraphicsLineItem *QgsLayoutGuide::item()
   return mLineItem.get();
 }
 
+double QgsLayoutGuide::layoutPosition() const
+{
+  switch ( mOrientation )
+  {
+    case Horizontal:
+      return mLineItem->line().y1();
+
+    case Vertical:
+      return mLineItem->line().x1();
+  }
+  return -999; // avoid warning
+}
+
 QgsLayoutGuide::Orientation QgsLayoutGuide::orientation() const
 {
   return mOrientation;

src/core/layout/qgslayoutguidecollection.h

@@ -31,9 +31,11 @@ class QGraphicsLineItem;
  * \brief Contains the configuration for a single snap guide used by a layout.
  * \since QGIS 3.0
  */
-class CORE_EXPORT QgsLayoutGuide
+class CORE_EXPORT QgsLayoutGuide : public QObject
 {
 
+    Q_OBJECT
+
   public:
 
     //! Guide orientation
@@ -98,6 +100,18 @@ class CORE_EXPORT QgsLayoutGuide
      */
     QGraphicsLineItem *item();
 
+    /**
+     * Returns the guide's position in absolute layout units.
+     */
+    double layoutPosition() const;
+
+  signals:
+
+    /**
+     * Emitted when the guide's position is changed.
+     */
+    void positionChanged();
+
   private:
 
     Orientation mOrientation = Vertical;

tests/src/python/test_qgslayoutguides.py

@@ -23,6 +23,7 @@
                        QgsLayoutItemPage)
 from qgis.PyQt.QtGui import (QPen,
                              QColor)
+from qgis.PyQt.QtTest import QSignalSpy
 
 from qgis.testing import start_app, unittest
 
@@ -40,9 +41,11 @@ def testGuideGettersSetters(self):
         self.assertEqual(g.position().length(), 5.0)
         self.assertEqual(g.position().units(), QgsUnitTypes.LayoutCentimeters)
 
+        position_changed_spy = QSignalSpy(g.positionChanged)
         g.setPosition(QgsLayoutMeasurement(15, QgsUnitTypes.LayoutInches))
         self.assertEqual(g.position().length(), 15.0)
         self.assertEqual(g.position().units(), QgsUnitTypes.LayoutInches)
+        self.assertEqual(len(position_changed_spy), 1)
 
         g.setPage(1)
         self.assertEqual(g.page(), 1)
@@ -59,6 +62,7 @@ def testUpdateGuide(self):
         self.assertEqual(g.item().line().y1(), 50)
         self.assertEqual(g.item().line().x2(), 297)
         self.assertEqual(g.item().line().y2(), 50)
+        self.assertEqual(g.layoutPosition(), 50)
 
         g.setPosition(QgsLayoutMeasurement(15, QgsUnitTypes.LayoutMillimeters))
         g.update()
@@ -67,6 +71,17 @@ def testUpdateGuide(self):
         self.assertEqual(g.item().line().y1(), 15)
         self.assertEqual(g.item().line().x2(), 297)
         self.assertEqual(g.item().line().y2(), 15)
+        self.assertEqual(g.layoutPosition(), 15)
+
+        # vertical guide
+        g2 = QgsLayoutGuide(l, QgsLayoutGuide.Vertical, QgsLayoutMeasurement(5, QgsUnitTypes.LayoutCentimeters))
+        g2.update()
+        self.assertTrue(g2.item().isVisible())
+        self.assertEqual(g2.item().line().x1(), 50)
+        self.assertEqual(g2.item().line().y1(), 0)
+        self.assertEqual(g2.item().line().x2(), 50)
+        self.assertEqual(g2.item().line().y2(), 210)
+        self.assertEqual(g2.layoutPosition(), 50)
 
         g.setPage(10)
         g.update()