Merge pull request #58122 from nyalldawson/painter_dpi_methods

Cleanup QPicture dpi scaling workarounds

python/PyQt6/core/auto_generated/effects/qgspainteffect.sip.in

@@ -305,13 +305,16 @@ effects.
 .. seealso:: :py:func:`sourceAsImage`
 %End
 
-    void fixQPictureDpi( QPainter *painter ) const;
+ void fixQPictureDpi( QPainter *painter ) const /Deprecated/;
 %Docstring
 Applies a workaround to a QPainter to avoid an issue with incorrect scaling
 when drawing QPictures. This may need to be called by derived classes prior
 to rendering results onto a painter.
 
 :param painter: destination painter
+
+.. deprecated::
+   QGIS 3.40, use :py:func:`QgsPainting.drawPicture()` or :py:func:`QgsPainting.applyScaleFixForQPictureDpi()` instead.
 %End
 
 };

python/PyQt6/core/auto_generated/painting/qgspainting.sip.in

@@ -87,6 +87,57 @@ Returns ``True`` if the triangle could be rendered, or ``False`` if it could not
 .. versionadded:: 3.34
 %End
 
+    static int qtDefaultDpiX();
+%Docstring
+Returns the default Qt horizontal DPI.
+
+.. note::
+
+   This method proxies the internal Qt :py:func:`~QgsPainting.qt_defaultDpiX` function.
+
+.. seealso:: :py:func:`qtDefaultDpiY`
+
+.. versionadded:: 3.40
+%End
+
+    static int qtDefaultDpiY();
+%Docstring
+Returns the default Qt vertical DPI.
+
+.. note::
+
+   This method proxies the internal Qt :py:func:`~QgsPainting.qt_defaultDpiY` function.
+
+.. seealso:: :py:func:`qtDefaultDpiX`
+
+.. versionadded:: 3.40
+%End
+
+    static void applyScaleFixForQPictureDpi( QPainter *painter );
+%Docstring
+Applies a workaround to a ``painter`` to avoid an issue with incorrect scaling
+when drawing QPictures.
+
+.. note::
+
+   This is a low-level method, which alters the ``painter`` state and relies on the
+   caller saving/restoring painter state accordingly. Consider using
+   the high-level :py:func:`~QgsPainting.drawPicture` method instead.
+
+.. seealso:: :py:func:`drawPicture`
+
+.. versionadded:: 3.40
+%End
+
+    static void drawPicture( QPainter *painter, const QPointF &point, const QPicture &picture );
+%Docstring
+Draws a picture onto a ``painter``, correctly applying workarounds to avoid issues
+with incorrect scaling.
+
+.. seealso:: :py:func:`applyScaleFixForQPictureDpi`
+
+.. versionadded:: 3.40
+%End
 };
 
 /************************************************************************

python/core/auto_generated/effects/qgspainteffect.sip.in

@@ -305,13 +305,16 @@ effects.
 .. seealso:: :py:func:`sourceAsImage`
 %End
 
-    void fixQPictureDpi( QPainter *painter ) const;
+ void fixQPictureDpi( QPainter *painter ) const /Deprecated/;
 %Docstring
 Applies a workaround to a QPainter to avoid an issue with incorrect scaling
 when drawing QPictures. This may need to be called by derived classes prior
 to rendering results onto a painter.
 
 :param painter: destination painter
+
+.. deprecated::
+   QGIS 3.40, use :py:func:`QgsPainting.drawPicture()` or :py:func:`QgsPainting.applyScaleFixForQPictureDpi()` instead.
 %End
 
 };

python/core/auto_generated/painting/qgspainting.sip.in

@@ -87,6 +87,57 @@ Returns ``True`` if the triangle could be rendered, or ``False`` if it could not
 .. versionadded:: 3.34
 %End
 
+    static int qtDefaultDpiX();
+%Docstring
+Returns the default Qt horizontal DPI.
+
+.. note::
+
+   This method proxies the internal Qt :py:func:`~QgsPainting.qt_defaultDpiX` function.
+
+.. seealso:: :py:func:`qtDefaultDpiY`
+
+.. versionadded:: 3.40
+%End
+
+    static int qtDefaultDpiY();
+%Docstring
+Returns the default Qt vertical DPI.
+
+.. note::
+
+   This method proxies the internal Qt :py:func:`~QgsPainting.qt_defaultDpiY` function.
+
+.. seealso:: :py:func:`qtDefaultDpiX`
+
+.. versionadded:: 3.40
+%End
+
+    static void applyScaleFixForQPictureDpi( QPainter *painter );
+%Docstring
+Applies a workaround to a ``painter`` to avoid an issue with incorrect scaling
+when drawing QPictures.
+
+.. note::
+
+   This is a low-level method, which alters the ``painter`` state and relies on the
+   caller saving/restoring painter state accordingly. Consider using
+   the high-level :py:func:`~QgsPainting.drawPicture` method instead.
+
+.. seealso:: :py:func:`drawPicture`
+
+.. versionadded:: 3.40
+%End
+
+    static void drawPicture( QPainter *painter, const QPointF &point, const QPicture &picture );
+%Docstring
+Draws a picture onto a ``painter``, correctly applying workarounds to avoid issues
+with incorrect scaling.
+
+.. seealso:: :py:func:`applyScaleFixForQPictureDpi`
+
+.. versionadded:: 3.40
+%End
 };
 
 /************************************************************************

src/app/qgisapp.cpp

@@ -177,8 +177,6 @@
 #include <QNetworkProxy>
 #include <QAuthenticator>
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-
 //
 // Mac OS X Includes
 // Must include before GEOS 3 due to unqualified use of 'Point'

src/app/qgsanimationexportdialog.cpp

@@ -28,8 +28,6 @@
 #include <QRegularExpression>
 #include <QRegularExpressionValidator>
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-
 QgsAnimationExportDialog::QgsAnimationExportDialog( QWidget *parent, QgsMapCanvas *mapCanvas, const QList< QgsMapDecoration * > &decorations )
   : QDialog( parent )
   , mMapCanvas( mapCanvas )

src/app/qgsmapsavedialog.cpp

@@ -47,8 +47,6 @@
 #include "qgsfileutils.h"
 #include "qgsannotationlayer.h"
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-
 QgsMapSaveDialog::QgsMapSaveDialog( QWidget *parent, QgsMapCanvas *mapCanvas, const QList<QgsMapDecoration *> &decorations, const QList< QgsAnnotation *> &annotations, DialogType type )
   : QDialog( parent )
   , mDialogType( type )

src/core/annotations/qgsannotation.cpp

@@ -24,12 +24,11 @@
 #include "qgssymbol.h"
 #include "qgsmarkersymbol.h"
 #include "qgsfillsymbol.h"
+#include "qgspainting.h"
 
 #include <QPen>
 #include <QPainter>
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-
 QgsAnnotation::QgsAnnotation( QObject *parent )
   : QObject( parent )
   , mMarkerSymbol( new QgsMarkerSymbol() )
@@ -329,7 +328,7 @@ void QgsAnnotation::_readXml( const QDomElement &annotationElem, const QgsReadWr
   }
 
   mContentsMargins = QgsMargins::fromString( annotationElem.attribute( QStringLiteral( "contentsMargin" ) ) );
-  const double dpiScale = 25.4 / qt_defaultDpiX();
+  const double dpiScale = 25.4 / QgsPainting::qtDefaultDpiX();
   if ( annotationElem.hasAttribute( QStringLiteral( "frameWidthMM" ) ) )
     mFrameSize.setWidth( annotationElem.attribute( QStringLiteral( "frameWidthMM" ), QStringLiteral( "5" ) ).toDouble() );
   else

src/core/effects/qgseffectstack.cpp

@@ -19,6 +19,7 @@
 #include "qgspainteffectregistry.h"
 #include "qgsrendercontext.h"
 #include "qgsapplication.h"
+#include "qgspainting.h"
 #include <QPicture>
 
 QgsEffectStack::QgsEffectStack( const QgsEffectStack &other )
@@ -136,9 +137,7 @@ void QgsEffectStack::draw( QgsRenderContext &context )
     QPicture *pic = results.takeLast();
     if ( mEffectList.at( i )->drawMode() != QgsPaintEffect::Modifier )
     {
-      const QgsScopedQPainterState painterState( context.painter() );
-      fixQPictureDpi( context.painter() );
-      context.painter()->drawPicture( 0, 0, *pic );
+      QgsPainting::drawPicture( context.painter(), QPointF( 0, 0 ), *pic );
     }
     delete pic;
   }

src/core/effects/qgspainteffect.cpp

@@ -20,10 +20,9 @@
 #include "qgslogger.h"
 #include "qgsrendercontext.h"
 #include "qgssymbollayerutils.h"
-#include <QPicture>
+#include "qgspainting.h"
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-Q_GUI_EXPORT extern int qt_defaultDpiY();
+#include <QPicture>
 
 QgsPaintEffect::QgsPaintEffect( const QgsPaintEffect &other )
   : mEnabled( other.enabled() )
@@ -132,9 +131,7 @@ void QgsPaintEffect::drawSource( QPainter &painter )
 {
   if ( requiresQPainterDpiFix )
   {
-    const QgsScopedQPainterState painterState( &painter );
-    fixQPictureDpi( &painter );
-    painter.drawPicture( 0, 0, *mPicture );
+    QgsPainting::drawPicture( &painter, QPointF( 0, 0 ), *mPicture );
   }
   else
   {
@@ -180,12 +177,7 @@ QRectF QgsPaintEffect::boundingRect( const QRectF &rect, const QgsRenderContext
 
 void QgsPaintEffect::fixQPictureDpi( QPainter *painter ) const
 {
-  // QPicture makes an assumption that we drawing to it with system DPI.
-  // Then when being drawn, it scales the painter. The following call
-  // negates the effect. There is no way of setting QPicture's DPI.
-  // See QTBUG-20361
-  painter->scale( static_cast< double >( qt_defaultDpiX() ) / painter->device()->logicalDpiX(),
-                  static_cast< double >( qt_defaultDpiY() ) / painter->device()->logicalDpiY() );
+  QgsPainting::applyScaleFixForQPictureDpi( painter );
 }
 
 QRectF QgsPaintEffect::imageBoundingRect( const QgsRenderContext &context ) const

src/core/effects/qgspainteffect.h

@@ -289,8 +289,10 @@ class CORE_EXPORT QgsPaintEffect SIP_NODEFAULTCTORS
      * when drawing QPictures. This may need to be called by derived classes prior
      * to rendering results onto a painter.
      * \param painter destination painter
+     *
+     * \deprecated QGIS 3.40, use QgsPainting::drawPicture() or QgsPainting::applyScaleFixForQPictureDpi() instead.
      */
-    void fixQPictureDpi( QPainter *painter ) const;
+    Q_DECL_DEPRECATED void fixQPictureDpi( QPainter *painter ) const SIP_DEPRECATED;
 
   private:
 

src/core/maprenderer/qgsmaprenderercustompainterjob.cpp

@@ -21,22 +21,10 @@
 #include "qgsmaplayerrenderer.h"
 #include "qgsmaplayerlistutils_p.h"
 #include "qgselevationmap.h"
+#include "qgspainting.h"
 
 #include <QtConcurrentRun>
 
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-Q_GUI_EXPORT extern int qt_defaultDpiY();
-
-static void _fixQPictureDPI( QPainter *p )
-{
-  // QPicture makes an assumption that we drawing to it with system DPI.
-  // Then when being drawn, it scales the painter. The following call
-  // negates the effect. There is no way of setting QPicture's DPI.
-  // See QTBUG-20361
-  p->scale( static_cast< double >( qt_defaultDpiX() ) / p->device()->logicalDpiX(),
-            static_cast< double >( qt_defaultDpiY() ) / p->device()->logicalDpiY() );
-}
-
 //
 // QgsMapRendererAbstractCustomPainterJob
 //
@@ -480,21 +468,15 @@ void QgsMapRendererCustomPainterJob::doRender()
         // if there is vector rendering we use it, else we use the raster rendering
         if ( job.picture )
         {
-          mPainter->save();
-          _fixQPictureDPI( mPainter );
-          mPainter->drawPicture( 0, 0, *job.picture );
-          mPainter->restore();
+          QgsPainting::drawPicture( mPainter, QPointF( 0, 0 ), *job.picture );
         }
         else
           mPainter->drawImage( 0, 0, *job.img );
       }
 
       if ( mLabelJob.picture )
       {
-        mPainter->save();
-        _fixQPictureDPI( mPainter );
-        mPainter->drawPicture( 0, 0, *mLabelJob.picture );
-        mPainter->restore();
+        QgsPainting::drawPicture( mPainter, QPointF( 0, 0 ), *mLabelJob.picture );
       }
     }
   }

src/core/painting/qgsgeometrypaintdevice.cpp

@@ -19,9 +19,7 @@
 #include "qgsgeos.h"
 #include "qgsmultipolygon.h"
 #include "qgsmultilinestring.h"
-
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-Q_GUI_EXPORT extern int qt_defaultDpiY();
+#include "qgspainting.h"
 
 //
 // QgsGeometryPaintEngine
@@ -652,18 +650,18 @@ int QgsGeometryPaintDevice::metric( PaintDeviceMetric m ) const
       val = static_cast< int >( mPaintEngine->geometry().boundingBox().height() );
       break;
     case PdmWidthMM:
-      val = static_cast< int >( 25.4 / qt_defaultDpiX() * mPaintEngine->geometry().boundingBox().width() );
+      val = static_cast< int >( 25.4 / QgsPainting::qtDefaultDpiX() * mPaintEngine->geometry().boundingBox().width() );
       break;
     case PdmHeightMM:
-      val = static_cast< int >( 25.4 / qt_defaultDpiY() * mPaintEngine->geometry().boundingBox().height() );
+      val = static_cast< int >( 25.4 / QgsPainting::qtDefaultDpiY() * mPaintEngine->geometry().boundingBox().height() );
       break;
     case PdmDpiX:
     case PdmPhysicalDpiX:
-      val = qt_defaultDpiX();
+      val = QgsPainting::qtDefaultDpiX();
       break;
     case PdmDpiY:
     case PdmPhysicalDpiY:
-      val = qt_defaultDpiY();
+      val = QgsPainting::qtDefaultDpiY();
       break;
     case PdmNumColors:
       val = 16777216;

src/core/painting/qgsmaskpaintdevice.cpp

@@ -14,10 +14,7 @@
  ***************************************************************************/
 
 #include "qgsmaskpaintdevice.h"
-
-
-Q_GUI_EXPORT extern int qt_defaultDpiX();
-Q_GUI_EXPORT extern int qt_defaultDpiY();
+#include "qgspainting.h"
 
 ///@cond PRIVATE
 
@@ -85,18 +82,18 @@ int QgsMaskPaintDevice::metric( PaintDeviceMetric m ) const
       val = static_cast< int >( mPaintEngine->maskPainterPath().boundingRect().height() );
       break;
     case PdmWidthMM:
-      val = static_cast< int >( 25.4 / qt_defaultDpiX() * mPaintEngine->maskPainterPath().boundingRect().width() );
+      val = static_cast< int >( 25.4 / QgsPainting::qtDefaultDpiX() * mPaintEngine->maskPainterPath().boundingRect().width() );
       break;
     case PdmHeightMM:
-      val = static_cast< int >( 25.4 / qt_defaultDpiY() * mPaintEngine->maskPainterPath().boundingRect().height() );
+      val = static_cast< int >( 25.4 / QgsPainting::qtDefaultDpiY() * mPaintEngine->maskPainterPath().boundingRect().height() );
       break;
     case PdmDpiX:
     case PdmPhysicalDpiX:
-      val = qt_defaultDpiX();
+      val = QgsPainting::qtDefaultDpiX();
       break;
     case PdmDpiY:
     case PdmPhysicalDpiY:
-      val = qt_defaultDpiY();
+      val = QgsPainting::qtDefaultDpiY();
       break;
     case PdmNumColors:
       val = 16777216;