[layouts] Ensures that 1:1 zoom level on layout designer accounts

for actual screen dpi, and responds correctly when window is dragged between screens
qgis · Jul 20, 2021 · 9328953 · 9328953
1 parent d8461a1
commit 9328953
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Showing 5 changed files with 69 additions and 2 deletions.
diff --git a/python/gui/auto_generated/layout/qgslayoutview.sip.in b/python/gui/auto_generated/layout/qgslayoutview.sip.in
@@ -579,6 +579,8 @@ but is still in a perfectly valid state.
 
     virtual void paintEvent( QPaintEvent *event );
 
+    virtual void showEvent( QShowEvent *event );
+
 
 };
 

diff --git a/src/app/layout/qgslayoutdesignerdialog.cpp b/src/app/layout/qgslayoutdesignerdialog.cpp
@@ -96,6 +96,8 @@
 #include <QClipboard>
 #include <QRegularExpression>
 #include <QUrl>
+#include <QWindow>
+#include <QScreen>
 
 #ifdef Q_OS_MACX
 #include <ApplicationServices/ApplicationServices.h>
@@ -1617,6 +1619,25 @@ void QgsLayoutDesignerDialog::dragEnterEvent( QDragEnterEvent *event )
   }
 }
 
+void QgsLayoutDesignerDialog::showEvent( QShowEvent *event )
+{
+  QMainWindow::showEvent( event );
+
+  updateDevicePixelFromScreen();
+  // keep device pixel ratio up to date on screen or resolution change
+  if ( window()->windowHandle() )
+  {
+    connect( window()->windowHandle(), &QWindow::screenChanged, this, [ = ]( QScreen * )
+    {
+      disconnect( mScreenDpiChangedConnection );
+      mScreenDpiChangedConnection = connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, this, &QgsLayoutDesignerDialog::updateDevicePixelFromScreen );
+      updateDevicePixelFromScreen();
+    } );
+
+    mScreenDpiChangedConnection = connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, this, &QgsLayoutDesignerDialog::updateDevicePixelFromScreen );
+  }
+}
+
 void QgsLayoutDesignerDialog::setTitle( const QString &title )
 {
   mTitle = title;
@@ -1801,7 +1822,7 @@ void QgsLayoutDesignerDialog::updateStatusZoom()
   }
   else
   {
-    double dpi = QgsApplication::desktop()->logicalDpiX();
+    double dpi = mScreenDpi;
     //monitor dpi is not always correct - so make sure the value is sane
     if ( ( dpi < 60 ) || ( dpi > 1200 ) )
       dpi = 72;
@@ -4924,6 +4945,13 @@ void QgsLayoutDesignerDialog::onItemAdded( QgsLayoutItem *item )
   }
 }
 
+void QgsLayoutDesignerDialog::updateDevicePixelFromScreen()
+{
+  if ( window()->windowHandle() )
+    mScreenDpi = window()->windowHandle()->screen()->physicalDotsPerInch();
+  updateStatusZoom();
+}
+
 void QgsLayoutDesignerDialog::storeExportResults( QgsLayoutExporter::ExportResult result, QgsLayoutExporter *exporter )
 {
   mLastExportResults = std::make_unique< QgsLayoutDesignerInterface::ExportResults >();

diff --git a/src/app/layout/qgslayoutdesignerdialog.h b/src/app/layout/qgslayoutdesignerdialog.h
@@ -354,6 +354,7 @@ class QgsLayoutDesignerDialog: public QMainWindow, public Ui::QgsLayoutDesignerB
     void closeEvent( QCloseEvent * ) override;
     void dropEvent( QDropEvent *event ) override;
     void dragEnterEvent( QDragEnterEvent *event ) override;
+    void showEvent( QShowEvent *event ) override;
 
   private slots:
 
@@ -417,6 +418,7 @@ class QgsLayoutDesignerDialog: public QMainWindow, public Ui::QgsLayoutDesignerB
     void backgroundTaskCountChanged( int total );
     void onMapPreviewRefreshed();
     void onItemAdded( QgsLayoutItem *item );
+    void updateDevicePixelFromScreen();
 
   private:
 
@@ -516,6 +518,9 @@ class QgsLayoutDesignerDialog: public QMainWindow, public Ui::QgsLayoutDesignerB
     std::unique_ptr< QgsLayoutDesignerInterface::ExportResults> mLastExportResults;
     QMap< QString, QgsLabelingResults *> mLastExportLabelingResults;
 
+    double mScreenDpi = 96.0;
+    QMetaObject::Connection mScreenDpiChangedConnection;
+
     //! Save window state
     void saveWindowState();
 

diff --git a/src/gui/layout/qgslayoutview.cpp b/src/gui/layout/qgslayoutview.cpp
@@ -42,6 +42,8 @@
 #include <QMenu>
 #include <QClipboard>
 #include <QMimeData>
+#include <QWindow>
+#include <QScreen>
 
 #define MIN_VIEW_SCALE 0.05
 #define MAX_VIEW_SCALE 1000.0
@@ -207,7 +209,7 @@ void QgsLayoutView::setZoomLevel( double level )
   }
   else
   {
-    double dpi = QgsApplication::desktop()->logicalDpiX();
+    double dpi = mScreenDpi;
     //monitor dpi is not always correct - so make sure the value is sane
     if ( ( dpi < 60 ) || ( dpi > 1200 ) )
       dpi = 72;
@@ -1154,6 +1156,25 @@ void QgsLayoutView::paintEvent( QPaintEvent *event )
   }
 }
 
+void QgsLayoutView::showEvent( QShowEvent *event )
+{
+  QGraphicsView::showEvent( event );
+
+  updateDevicePixelFromScreen();
+  // keep device pixel ratio up to date on screen or resolution change
+  if ( window()->windowHandle() )
+  {
+    connect( window()->windowHandle(), &QWindow::screenChanged, this, [ = ]( QScreen * )
+    {
+      disconnect( mScreenDpiChangedConnection );
+      mScreenDpiChangedConnection = connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, this, &QgsLayoutView::updateDevicePixelFromScreen );
+      updateDevicePixelFromScreen();
+    } );
+
+    mScreenDpiChangedConnection = connect( window()->windowHandle()->screen(), &QScreen::physicalDotsPerInchChanged, this, &QgsLayoutView::updateDevicePixelFromScreen );
+  }
+}
+
 void QgsLayoutView::invalidateCachedRenders()
 {
   if ( !currentLayout() )
@@ -1169,6 +1190,12 @@ void QgsLayoutView::invalidateCachedRenders()
   }
 }
 
+void QgsLayoutView::updateDevicePixelFromScreen()
+{
+  if ( window()->windowHandle() )
+    mScreenDpi = window()->windowHandle()->screen()->physicalDotsPerInch();
+}
+
 void QgsLayoutView::viewChanged()
 {
   if ( mHorizontalRuler )

diff --git a/src/gui/layout/qgslayoutview.h b/src/gui/layout/qgslayoutview.h
@@ -544,10 +544,12 @@ class GUI_EXPORT QgsLayoutView: public QGraphicsView
     void scrollContentsBy( int dx, int dy ) override;
     void dragEnterEvent( QDragEnterEvent *e ) override;
     void paintEvent( QPaintEvent *event ) override;
+    void showEvent( QShowEvent *event ) override;
 
   private slots:
 
     void invalidateCachedRenders();
+    void updateDevicePixelFromScreen();
 
   private:
 
@@ -578,6 +580,9 @@ class GUI_EXPORT QgsLayoutView: public QGraphicsView
 
     bool mPaintingEnabled = true;
 
+    double mScreenDpi = 96.0;
+    QMetaObject::Connection mScreenDpiChangedConnection;
+
     friend class TestQgsLayoutView;
     friend class QgsLayoutMouseHandles;