[layouts] Fix items disappear in designer with 90 or 270 degree

rotation Caused by Qt bug 66185 Fixes #18027
qgis · Feb 5, 2018 · 345dd0c · 345dd0c
1 parent df76bfc
commit 345dd0c
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Showing 8 changed files with 48 additions and 13 deletions.
diff --git a/python/core/layout/qgslayoututils.sip.in b/python/core/layout/qgslayoututils.sip.in
@@ -9,7 +9,6 @@
 
 
 
-
 class QgsLayoutUtils
 {
 %Docstring
@@ -219,6 +218,11 @@ the a specified ``rotation`` amount.
 Decodes a ``string`` representing a paper orientation and returns the
 decoded orientation.
 If the string was correctly decoded, ``ok`` will be set to true.
+%End
+
+    static double scaleFactorFromItemStyle( const QStyleOptionGraphicsItem *style );
+%Docstring
+Extracts the scale factor from an item ``style``.
 %End
 
 };

diff --git a/src/core/layout/qgslayoutitem.cpp b/src/core/layout/qgslayoutitem.cpp
@@ -244,7 +244,7 @@ void QgsLayoutItem::paint( QPainter *painter, const QStyleOptionGraphicsItem *it
   }
 
   bool previewRender = !mLayout || mLayout->renderContext().isPreviewRender();
-  double destinationDpi = previewRender ? itemStyle->matrix.m11() * 25.4 : mLayout->renderContext().dpi();
+  double destinationDpi = previewRender ? QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle ) * 25.4 : mLayout->renderContext().dpi();
   bool useImageCache = false;
   bool forceRasterOutput = containsAdvancedEffects() && ( !mLayout || !( mLayout->renderContext().flags() & QgsLayoutRenderContext::FlagForceVectorOutput ) );
 
@@ -255,8 +255,8 @@ void QgsLayoutItem::paint( QPainter *painter, const QStyleOptionGraphicsItem *it
 
     if ( previewRender )
     {
-      widthInPixels = boundingRect().width() * itemStyle->matrix.m11();
-      heightInPixels = boundingRect().height() * itemStyle->matrix.m11();
+      widthInPixels = boundingRect().width() * QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle );
+      heightInPixels = boundingRect().height() * QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle );
     }
     else
     {

diff --git a/src/core/layout/qgslayoutitemmap.cpp b/src/core/layout/qgslayoutitemmap.cpp
@@ -780,7 +780,7 @@ void QgsLayoutItemMap::paint( QPainter *painter, const QStyleOptionGraphicsItem
       if ( !mPainterJob && !mDrawingPreview )
       {
         // this is the map's very first paint - trigger a cache update
-        mPreviewScaleFactor = style->matrix.m11();
+        mPreviewScaleFactor = QgsLayoutUtils::scaleFactorFromItemStyle( style );
         mBackgroundUpdateTimer->start( 1 );
       }
     }
@@ -789,7 +789,7 @@ void QgsLayoutItemMap::paint( QPainter *painter, const QStyleOptionGraphicsItem
       if ( mCacheInvalidated && !mDrawingPreview )
       {
         // cache was invalidated - trigger a background update
-        mPreviewScaleFactor = style->matrix.m11();
+        mPreviewScaleFactor = QgsLayoutUtils::scaleFactorFromItemStyle( style );
         mBackgroundUpdateTimer->start( 1 );
       }
 
@@ -841,7 +841,7 @@ void QgsLayoutItemMap::paint( QPainter *painter, const QStyleOptionGraphicsItem
     if ( containsAdvancedEffects() && ( !mLayout || !( mLayout->renderContext().flags() & QgsLayoutRenderContext::FlagForceVectorOutput ) ) )
     {
       // rasterize
-      double destinationDpi = style->matrix.m11() * 25.4;
+      double destinationDpi = QgsLayoutUtils::scaleFactorFromItemStyle( style ) * 25.4;
       double layoutUnitsInInches = mLayout ? mLayout->convertFromLayoutUnits( 1, QgsUnitTypes::LayoutInches ).length() : 1;
       int widthInPixels = std::round( boundingRect().width() * layoutUnitsInInches * destinationDpi );
       int heightInPixels = std::round( boundingRect().height() * layoutUnitsInInches * destinationDpi );

diff --git a/src/core/layout/qgslayoutitemnodeitem.cpp b/src/core/layout/qgslayoutitemnodeitem.cpp
@@ -19,6 +19,7 @@
 #include "qgssymbol.h"
 #include "qgsmapsettings.h"
 #include "qgslayout.h"
+#include "qgslayoututils.h"
 #include <limits>
 #include <cmath>
 #include <QStyleOptionGraphicsItem>
@@ -164,7 +165,7 @@ void QgsLayoutNodesItem::drawNodes( QgsRenderContext &context, const QStyleOptio
 {
   context.painter()->setRenderHint( QPainter::Antialiasing, false );
 
-  double rectSize = 9.0 / itemStyle->matrix.m11();
+  double rectSize = 9.0 / QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle );
 
   QgsStringMap properties;
   properties.insert( QStringLiteral( "name" ), QStringLiteral( "cross" ) );
@@ -177,7 +178,7 @@ void QgsLayoutNodesItem::drawNodes( QgsRenderContext &context, const QStyleOptio
 
   symbol->startRender( context );
   for ( QPointF pt : mPolygon )
-    symbol->renderPoint( pt * itemStyle->matrix.m11(), nullptr, context );
+    symbol->renderPoint( pt * QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle ), nullptr, context );
   symbol->stopRender( context );
 
   if ( mSelectedNode >= 0 && mSelectedNode < mPolygon.size() )
@@ -186,7 +187,7 @@ void QgsLayoutNodesItem::drawNodes( QgsRenderContext &context, const QStyleOptio
 
 void QgsLayoutNodesItem::drawSelectedNode( QgsRenderContext &context, const QStyleOptionGraphicsItem *itemStyle ) const
 {
-  double rectSize = 9.0 / itemStyle->matrix.m11();
+  double rectSize = 9.0 / QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle );
 
   QgsStringMap properties;
   properties.insert( QStringLiteral( "name" ), QStringLiteral( "square" ) );
@@ -199,7 +200,7 @@ void QgsLayoutNodesItem::drawSelectedNode( QgsRenderContext &context, const QSty
   symbol->setSize( rectSize );
 
   symbol->startRender( context );
-  symbol->renderPoint( mPolygon.at( mSelectedNode ) * itemStyle->matrix.m11(), nullptr, context );
+  symbol->renderPoint( mPolygon.at( mSelectedNode ) * QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle ), nullptr, context );
   symbol->stopRender( context );
 }
 

diff --git a/src/core/layout/qgslayoutitempage.cpp b/src/core/layout/qgslayoutitempage.cpp
@@ -329,7 +329,7 @@ void QgsLayoutItemPageGrid::paint( QPainter *painter, const QStyleOptionGraphics
       {
         //dots are actually drawn as tiny crosses a few pixels across
         //set halfCrossLength to equivalent of 1 pixel
-        halfCrossLength = 1 / itemStyle->matrix.m11();
+        halfCrossLength = 1 / QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle );
       }
       else
       {

diff --git a/src/core/layout/qgslayoututils.cpp b/src/core/layout/qgslayoututils.cpp
@@ -19,6 +19,7 @@
 #include "qgslayout.h"
 #include "qgsrendercontext.h"
 #include "qgslayoutitemmap.h"
+#include <QStyleOptionGraphicsItem>
 #include <QPainter>
 #include <cmath>
 
@@ -381,6 +382,19 @@ QgsLayoutItemPage::Orientation QgsLayoutUtils::decodePaperOrientation( const QSt
   return QgsLayoutItemPage::Landscape; // default to landscape
 }
 
+double QgsLayoutUtils::scaleFactorFromItemStyle( const QStyleOptionGraphicsItem *style )
+{
+  // workaround Qt bug 66185
+
+  // Refs #18027 - if a QGraphicsItem is rotated by 90 or 270 degrees, then the item
+  // style given to QGraphicsItem::paint incorrectly uses the shear parameter of the matrix (m12)
+  // to store the current view scale, instead of the horizontal scale parameter (m11) which
+  // is used in all other cases
+
+  // TODO - ifdef this out if Qt fixes upstream
+  return !qgsDoubleNear( style->matrix.m11(), 0.0 ) ? style->matrix.m11() : style->matrix.m12();
+}
+
 double QgsLayoutUtils::pointsToMM( const double pointSize )
 {
   //conversion to mm based on 1 point = 1/72 inch

diff --git a/src/core/layout/qgslayoututils.h b/src/core/layout/qgslayoututils.h
@@ -27,7 +27,7 @@ class QgsLayout;
 class QgsLayoutItemMap;
 class QPainter;
 class QRectF;
-
+class QStyleOptionGraphicsItem;
 
 /**
  * \ingroup core
@@ -206,6 +206,11 @@ class CORE_EXPORT QgsLayoutUtils
      */
     static QgsLayoutItemPage::Orientation decodePaperOrientation( const QString &string, bool &ok );
 
+    /**
+     * Extracts the scale factor from an item \a style.
+     */
+    static double scaleFactorFromItemStyle( const QStyleOptionGraphicsItem *style );
+
   private:
 
     //! Scale factor for upscaling fontsize and downscaling painter

diff --git a/tests/src/core/testqgslayoututils.cpp b/tests/src/core/testqgslayoututils.cpp
@@ -22,6 +22,7 @@
 #include "qgslayoutitemmap.h"
 #include "qgsfontutils.h"
 #include "qgsrenderchecker.h"
+#include <QStyleOptionGraphicsItem>
 
 class TestQgsLayoutUtils: public QObject
 {
@@ -52,6 +53,7 @@ class TestQgsLayoutUtils: public QObject
     void drawTextRect(); //test drawing text in a rect
     void largestRotatedRect(); //test largest rotated rect helper function
     void decodePaperOrientation();
+    void scaleFactorFromItemStyle();
 
   private:
 
@@ -627,6 +629,15 @@ void TestQgsLayoutUtils::decodePaperOrientation()
   QCOMPARE( orientation, QgsLayoutItemPage::Landscape );
 }
 
+void TestQgsLayoutUtils::scaleFactorFromItemStyle()
+{
+  QStyleOptionGraphicsItem style;
+  style.matrix = QMatrix( 2, 0, 0, 0, 0, 0 );
+  QCOMPARE( QgsLayoutUtils::scaleFactorFromItemStyle( &style ), 2.0 );
+  style.matrix = QMatrix( 0, 2, 0, 0, 0, 0 );
+  QCOMPARE( QgsLayoutUtils::scaleFactorFromItemStyle( &style ), 2.0 );
+}
+
 bool TestQgsLayoutUtils::renderCheck( const QString &testName, QImage &image, int mismatchCount )
 {
   mReport += "<h2>" + testName + "</h2>\n";