Initial fix for #3975, label engine vectorizing texts in SVG and PDF output

- Add labeling engine option to render text-as-text
- Default is still text-as-outlines (vectorized), due to differences between text (as text) and buffer (as outline) methods
- Good output with printing to PDF (searchable, selectable text and embedded fonts)
- OK output with SVG, but differences between text (as text) and buffer (as outline) methods

Does not yet include unit tests or auto-setting of text-as-text for SVG output

Author: dakcarto

python/core/qgspallabeling.sip

@@ -666,6 +666,10 @@ class QgsPalLabeling : QgsLabelingEngineInterface
     bool isShowingPartialsLabels() const;
     void setShowingPartialsLabels( bool showing );
 
+    //! @note added in 2.4
+    bool isDrawingOutlineLabels() const;
+    void setDrawingOutlineLabels( bool outline );
+
     // implemented methods from labeling engine interface
 
     //! called when we're going to start with rendering

src/app/qgslabelengineconfigdialog.cpp

@@ -46,6 +46,7 @@ QgsLabelEngineConfigDialog::QgsLabelEngineConfigDialog( QWidget* parent )
   mShadowDebugRectChkBox->setChecked( lbl.isShowingShadowRectangles() );
 
   chkShowPartialsLabels->setChecked( lbl.isShowingPartialsLabels() );
+  mDrawOutlinesChkBox->setChecked( lbl.isDrawingOutlineLabels() );
 }
 
 
@@ -64,6 +65,7 @@ void QgsLabelEngineConfigDialog::onOK()
   lbl.setShowingShadowRectangles( mShadowDebugRectChkBox->isChecked() );
   lbl.setShowingAllLabels( chkShowAllLabels->isChecked() );
   lbl.setShowingPartialsLabels( chkShowPartialsLabels->isChecked() );
+  lbl.setDrawingOutlineLabels( mDrawOutlinesChkBox->isChecked() );
 
   lbl.saveEngineSettings();
 
@@ -81,4 +83,5 @@ void QgsLabelEngineConfigDialog::setDefaults()
   chkShowAllLabels->setChecked( false );
   mShadowDebugRectChkBox->setChecked( false );
   chkShowPartialsLabels->setChecked( p.getShowPartial() );
+  mDrawOutlinesChkBox->setChecked( true );
 }

src/core/qgspallabeling.cpp

@@ -3211,6 +3211,7 @@ QgsPalLabeling::QgsPalLabeling()
   mShowingShadowRects = false;
   mShowingAllLabels = false;
   mShowingPartialsLabels = p.getShowPartial();
+  mDrawOutlineLabels = true;
 }
 
 QgsPalLabeling::~QgsPalLabeling()
@@ -4443,6 +4444,11 @@ void QgsPalLabeling::drawLabel( pal::LabelPosition* label, QgsRenderContext& con
         textp.setPen( Qt::NoPen );
         textp.setBrush( tmpLyr.textColor );
         textp.drawPath( path );
+        // TODO: why are some font settings lost on drawPicture() when using drawText() inside QPicture?
+        //       e.g. some capitalization options, but not others
+        //textp.setFont( tmpLyr.textFont );
+        //textp.setPen( tmpLyr.textColor );
+        //textp.drawText( 0, 0, component.text() );
         textp.end();
 
         if ( tmpLyr.shadowDraw && tmpLyr.shadowUnder == QgsPalLayerSettings::ShadowText )
@@ -4459,20 +4465,24 @@ void QgsPalLabeling::drawLabel( pal::LabelPosition* label, QgsRenderContext& con
         {
           painter->setCompositionMode( tmpLyr.blendMode );
         }
-//        painter->setPen( Qt::NoPen );
-//        painter->setBrush( tmpLyr.textColor );
-//        painter->drawPath( path );
 
         // scale for any print output or image saving @ specific dpi
         painter->scale( component.dpiRatio(), component.dpiRatio() );
-        _fixQPictureDPI( painter );
-        painter->drawPicture( 0, 0, textPict );
-
-        // regular text draw, for testing optimization
-//        painter->setFont( tmpLyr.textFont );
-//        painter->setPen( tmpLyr.textColor );
-//        painter->drawText( 0, 0, multiLineList.at( i ) );
 
+        if ( mDrawOutlineLabels )
+        {
+          // draw outlined text
+          _fixQPictureDPI( painter );
+          painter->drawPicture( 0, 0, textPict );
+        }
+        else
+        {
+          // draw text as text (for SVG and PDF exports)
+          painter->setFont( tmpLyr.textFont );
+          painter->setPen( tmpLyr.textColor );
+          painter->setRenderHint( QPainter::TextAntialiasing );
+          painter->drawText( 0, 0, component.text() );
+        }
       }
       painter->restore();
     }
@@ -5004,6 +5014,8 @@ void QgsPalLabeling::loadEngineSettings()
                         "PAL", "/ShowingAllLabels", false, &saved );
   mShowingPartialsLabels = QgsProject::instance()->readBoolEntry(
                              "PAL", "/ShowingPartialsLabels", p.getShowPartial(), &saved );
+  mDrawOutlineLabels = QgsProject::instance()->readBoolEntry(
+                         "PAL", "/DrawOutlineLabels", true, &saved );
 }
 
 void QgsPalLabeling::saveEngineSettings()
@@ -5016,6 +5028,7 @@ void QgsPalLabeling::saveEngineSettings()
   QgsProject::instance()->writeEntry( "PAL", "/ShowingShadowRects", mShowingShadowRects );
   QgsProject::instance()->writeEntry( "PAL", "/ShowingAllLabels", mShowingAllLabels );
   QgsProject::instance()->writeEntry( "PAL", "/ShowingPartialsLabels", mShowingPartialsLabels );
+  QgsProject::instance()->writeEntry( "PAL", "/DrawOutlineLabels", mDrawOutlineLabels );
 }
 
 void QgsPalLabeling::clearEngineSettings()
@@ -5028,6 +5041,7 @@ void QgsPalLabeling::clearEngineSettings()
   QgsProject::instance()->removeEntry( "PAL", "/ShowingShadowRects" );
   QgsProject::instance()->removeEntry( "PAL", "/ShowingAllLabels" );
   QgsProject::instance()->removeEntry( "PAL", "/ShowingPartialsLabels" );
+  QgsProject::instance()->removeEntry( "PAL", "/DrawOutlineLabels" );
 }
 
 QgsLabelingEngineInterface* QgsPalLabeling::clone()
@@ -5037,6 +5051,7 @@ QgsLabelingEngineInterface* QgsPalLabeling::clone()
   lbl->mShowingCandidates = mShowingCandidates;
   lbl->mShowingShadowRects = mShowingShadowRects;
   lbl->mShowingPartialsLabels = mShowingPartialsLabels;
+  lbl->mDrawOutlineLabels = mDrawOutlineLabels;
   return lbl;
 }
 

src/core/qgspallabeling.h

@@ -740,6 +740,10 @@ class CORE_EXPORT QgsPalLabeling : public QgsLabelingEngineInterface
     bool isShowingPartialsLabels() const { return mShowingPartialsLabels; }
     void setShowingPartialsLabels( bool showing ) { mShowingPartialsLabels = showing; }
 
+    //! @note added in 2.4
+    bool isDrawingOutlineLabels() const { return mDrawOutlineLabels; }
+    void setDrawingOutlineLabels( bool outline ) { mDrawOutlineLabels = outline; }
+
     // implemented methods from labeling engine interface
 
     //! called when we're going to start with rendering
@@ -856,6 +860,7 @@ class CORE_EXPORT QgsPalLabeling : public QgsLabelingEngineInterface
     bool mShowingAllLabels; // whether to avoid collisions or not
     bool mShowingShadowRects; // whether to show debugging rectangles for drop shadows
     bool mShowingPartialsLabels; // whether to avoid partials labels or not
+    bool mDrawOutlineLabels; // whether to draw labels as text or outlines
 
     QgsLabelingResults* mResults;
 };

src/ui/qgsengineconfigdialog.ui

@@ -215,43 +215,41 @@
      <property name="verticalSpacing">
       <number>6</number>
      </property>
-     <item row="2" column="0">
-      <spacer name="horizontalSpacer_3">
+     <item row="1" column="0" colspan="3">
+      <widget class="QCheckBox" name="chkShowPartialsLabels">
+       <property name="text">
+        <string>Show partials labels</string>
+       </property>
+      </widget>
+     </item>
+     <item row="5" column="0" colspan="3">
+      <widget class="QCheckBox" name="mShadowDebugRectChkBox">
+       <property name="text">
+        <string>Show shadow rectangles (for debugging)</string>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="2">
+      <spacer name="horizontalSpacer_4">
        <property name="orientation">
         <enum>Qt::Horizontal</enum>
        </property>
-       <property name="sizeType">
-        <enum>QSizePolicy::Fixed</enum>
-       </property>
        <property name="sizeHint" stdset="0">
         <size>
-         <width>8</width>
-         <height>8</height>
+         <width>0</width>
+         <height>20</height>
         </size>
        </property>
       </spacer>
      </item>
-     <item row="1" column="0" colspan="3">
-      <widget class="QCheckBox" name="chkShowAllLabels">
-       <property name="sizePolicy">
-        <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
-         <horstretch>0</horstretch>
-         <verstretch>0</verstretch>
-        </sizepolicy>
-       </property>
-       <property name="text">
-        <string>Show all labels and features for all layers</string>
-       </property>
-      </widget>
-     </item>
-     <item row="3" column="0" colspan="3">
+     <item row="4" column="0" colspan="3">
       <widget class="QCheckBox" name="chkShowCandidates">
        <property name="text">
         <string>Show candidates (for debugging)</string>
        </property>
       </widget>
      </item>
-     <item row="2" column="1">
+     <item row="3" column="1">
       <widget class="QLabel" name="label_6">
        <property name="sizePolicy">
         <sizepolicy hsizetype="Maximum" vsizetype="Preferred">
@@ -264,30 +262,39 @@
        </property>
       </widget>
      </item>
-     <item row="2" column="2">
-      <spacer name="horizontalSpacer_4">
+     <item row="2" column="0" colspan="3">
+      <widget class="QCheckBox" name="chkShowAllLabels">
+       <property name="sizePolicy">
+        <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
+         <horstretch>0</horstretch>
+         <verstretch>0</verstretch>
+        </sizepolicy>
+       </property>
+       <property name="text">
+        <string>Show all labels and features for all layers</string>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="0">
+      <spacer name="horizontalSpacer_3">
        <property name="orientation">
         <enum>Qt::Horizontal</enum>
        </property>
+       <property name="sizeType">
+        <enum>QSizePolicy::Fixed</enum>
+       </property>
        <property name="sizeHint" stdset="0">
         <size>
-         <width>0</width>
-         <height>20</height>
+         <width>8</width>
+         <height>8</height>
         </size>
        </property>
       </spacer>
      </item>
-     <item row="4" column="0" colspan="3">
-      <widget class="QCheckBox" name="mShadowDebugRectChkBox">
-       <property name="text">
-        <string>Show shadow rectangles (for debugging)</string>
-       </property>
-      </widget>
-     </item>
      <item row="0" column="0" colspan="3">
-      <widget class="QCheckBox" name="chkShowPartialsLabels">
+      <widget class="QCheckBox" name="mDrawOutlinesChkBox">
        <property name="text">
-        <string>Show partials labels</string>
+        <string>Draw text as outlines (recommended)</string>
        </property>
       </widget>
      </item>