Consider also font descent and baseline in QgsComposerLabel::adjustSizeToText. Funded by Sourcepole QGIS Enterprise.

Author: manisandro

python/core/composer/qgscomposeritem.sip

@@ -405,8 +405,14 @@ class QgsComposerItem : QObject, QGraphicsRectItem
     /**Returns the font ascent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
     double fontAscentMillimeters( const QFont& font ) const;
 
-    /**Returns the font ascent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
+    /**Returns the font descent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
     double fontDescentMillimeters( const QFont& font ) const;
+    
+    /**Returns the font height in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE.
+     * Font height equals the font ascent+descent+1 (for baseline).
+     * @note Added in version 2.4
+    */
+    double fontHeightMillimeters( const QFont& font ) const;
 
     /**Calculates font to from point size to pixel size*/
     double pixelFontSize( double pointSize ) const;

src/core/composer/qgscomposeritem.cpp

@@ -749,6 +749,13 @@ double QgsComposerItem::fontDescentMillimeters( const QFont& font ) const
   return ( fontMetrics.descent() / FONT_WORKAROUND_SCALE );
 }
 
+double QgsComposerItem::fontHeightMillimeters( const QFont& font ) const
+{
+  QFont metricsFont = scaledFontPixelSize( font );
+  QFontMetricsF fontMetrics( metricsFont );
+  return ( fontMetrics.height() / FONT_WORKAROUND_SCALE );
+}
+
 double QgsComposerItem::pixelFontSize( double pointSize ) const
 {
   return ( pointSize * 0.3527 );

src/core/composer/qgscomposeritem.h

@@ -360,9 +360,15 @@ class CORE_EXPORT QgsComposerItem: public QObject, public QGraphicsRectItem
     /**Returns the font ascent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
     double fontAscentMillimeters( const QFont& font ) const;
 
-    /**Returns the font ascent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
+    /**Returns the font descent in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
     double fontDescentMillimeters( const QFont& font ) const;
 
+    /**Returns the font height in Millimeters (considers upscaling and downscaling with FONT_WORKAROUND_SCALE.
+     * Font height equals the font ascent+descent+1 (for baseline).
+     * @note Added in version 2.4
+    */
+    double fontHeightMillimeters( const QFont& font ) const;
+
     /**Calculates font to from point size to pixel size*/
     double pixelFontSize( double pointSize ) const;
 

src/core/composer/qgscomposerlabel.cpp

@@ -254,10 +254,10 @@ void QgsComposerLabel::setFont( const QFont& f )
 void QgsComposerLabel::adjustSizeToText()
 {
   double textWidth = textWidthMillimeters( mFont, displayText() );
-  double fontAscent = fontAscentMillimeters( mFont );
+  double fontHeight = fontHeightMillimeters( mFont );
 
   double width = textWidth + 2 * mMargin + 2 * pen().widthF() + 1;
-  double height = fontAscent + 2 * mMargin + 2 * pen().widthF() + 1;
+  double height = fontHeight + 2 * mMargin + 2 * pen().widthF();
 
   //keep alignment point constant
   double xShift = 0;