Use qt font bug workaround for composer label. Other items will follow soon. All the up-and downscaling is done in a central place in composer item base class.

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@9260 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: mhugent

src/core/composer/qgscomposeritem.cpp

@@ -27,6 +27,8 @@
 #include "qgsrect.h" //just for debugging
 #include "qgslogger.h"
 
+#define FONT_WORKAROUND_SCALE 10 //scale factor for upscaling fontsize and downscaling painter
+
 QgsComposerItem::QgsComposerItem( QgsComposition* composition ): QGraphicsRectItem( 0 ), mComposition( composition ), mBoundingResizeRectangle( 0 ), mFrame( true )
 {
   setFlag( QGraphicsItem::ItemIsSelectable, true );
@@ -520,3 +522,57 @@ void QgsComposerItem::hoverMoveEvent( QGraphicsSceneHoverEvent * event )
     setCursor( cursorForPosition( event->pos() ) );
   }
 }
+
+void QgsComposerItem::drawText(QPainter* p, int x, int y, const QString& text, const QFont& font)
+{
+  QFont textFont = scaledFontPixelSize(font);
+  
+  p->save();
+  p->setFont(textFont);
+  double scaleFactor = 1.0 / FONT_WORKAROUND_SCALE;
+  p->scale(scaleFactor, scaleFactor);
+  p->drawText(x * FONT_WORKAROUND_SCALE, y * FONT_WORKAROUND_SCALE, text);
+  p->restore();
+}
+
+void QgsComposerItem::drawText(QPainter* p, const QRectF& rect, const QString& text, const QFont& font)
+{
+  QFont textFont = scaledFontPixelSize(font);
+
+  QRectF scaledRect(rect.x() * FONT_WORKAROUND_SCALE, rect.y() * FONT_WORKAROUND_SCALE, 
+		    rect.width() * FONT_WORKAROUND_SCALE, rect.height() * FONT_WORKAROUND_SCALE);
+
+  p->save();
+  p->setFont(textFont);
+  double scaleFactor = 1.0 / FONT_WORKAROUND_SCALE;
+  p->scale(scaleFactor, scaleFactor);
+  p->drawText(scaledRect, Qt::AlignLeft | Qt::AlignTop | Qt::TextWordWrap, text);
+  p->restore();
+}
+
+double QgsComposerItem::textWidthMM(const QFont& font, const QString& text) const
+{
+  QFont metricsFont = scaledFontPixelSize(font);
+  QFontMetrics fontMetrics(metricsFont);
+  return (fontMetrics.width(text) / FONT_WORKAROUND_SCALE);
+}
+
+double QgsComposerItem::fontAscentMM(const QFont& font) const
+{
+  QFont metricsFont = scaledFontPixelSize(font);
+  QFontMetrics fontMetrics(metricsFont);
+  return (fontMetrics.ascent() / FONT_WORKAROUND_SCALE);
+}
+
+double QgsComposerItem::pixelFontSize(double pointSize) const
+{
+  return (pointSize * 0.3527);
+}
+
+QFont QgsComposerItem::scaledFontPixelSize(const QFont& font) const
+{
+  QFont scaledFont = font;
+  double pixelSize = pixelFontSize(font.pointSizeF()) * FONT_WORKAROUND_SCALE + 0.5;
+  scaledFont.setPixelSize(pixelSize);
+  return scaledFont;
+}

src/core/composer/qgscomposeritem.h

@@ -151,6 +151,25 @@ class CORE_EXPORT QgsComposerItem: public QGraphicsRectItem
 
     /**Draw background*/
     virtual void drawBackground( QPainter* p );
+
+    /**Draws Text. Takes care about all the composer specific issues (calculation to pixel, scaling of font and painter
+     to work arount the Qt font bug)*/
+    void drawText(QPainter* p, int x, int y, const QString& text, const QFont& font);
+
+    /**Like the above, but with a rectangle for multiline text*/
+    void drawText(QPainter* p, const QRectF& rect, const QString& text, const QFont& font);
+
+    /**Returns the font width in MM (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
+    double textWidthMM(const QFont& font, const QString& text) const;
+
+    /**Returns the font ascent in MM (considers upscaling and downscaling with FONT_WORKAROUND_SCALE*/
+    double fontAscentMM(const QFont& font) const;
+
+    /**Calculates font to from point size to pixel size*/
+    double pixelFontSize(double pointSize) const;
+
+    /**Returns a font where size is in pixel and font size is upscaled with FONT_WORKAROUND_SCALE*/
+    QFont scaledFontPixelSize(const QFont& font) const;
 };
 
 #endif

src/core/composer/qgscomposerlabel.cpp

@@ -19,17 +19,10 @@
 #include <QDomElement>
 #include <QPainter>
 
-QgsComposerLabel::QgsComposerLabel( QgsComposition *composition ): QgsComposerItem( composition ), mMargin( 0.0 )
+QgsComposerLabel::QgsComposerLabel( QgsComposition *composition ): QgsComposerItem( composition ), mMargin( 1.0 )
 {
   //default font size is 10 point
-  if ( mComposition )
-  {
-    mFont.setPixelSize( mComposition->pixelFontSize( 10 ) );
-  }
-  else
-  {
-    mFont.setPixelSize( 4 );
-  }
+  mFont.setPointSizeF(10);
 }
 
 QgsComposerLabel::~QgsComposerLabel()
@@ -53,8 +46,8 @@ void QgsComposerLabel::paint( QPainter* painter, const QStyleOptionGraphicsItem*
   double penWidth = pen().widthF();
   QRectF painterRect( penWidth + mMargin, penWidth + mMargin, rect().width() - 2 * penWidth - 2 * mMargin,
                       rect().height() - 2 * penWidth - 2 * mMargin);
-  painter->drawText( painterRect, Qt::AlignLeft | Qt::AlignTop | Qt::TextWordWrap, mText );
-
+  //painter->drawText( painterRect, Qt::AlignLeft | Qt::AlignTop | Qt::TextWordWrap, mText );
+  drawText(painter, painterRect, mText, mFont);
 
   drawFrame( painter );
   if ( isSelected() )
@@ -70,34 +63,20 @@ void QgsComposerLabel::setText( const QString& text )
 
 void QgsComposerLabel::setFont( const QFont& f )
 {
-  //set font size in pixels for proper preview and printout
-  if ( mComposition )
-  {
-    int pixelSize = mComposition->pixelFontSize( f.pointSizeF() );
-    mFont = f;
-    mFont.setPixelSize( pixelSize );
-  }
-  else
-  {
-    mFont = f;
-  }
+  mFont = f;
 }
 
 void QgsComposerLabel::adjustSizeToText()
 {
-  QFontMetricsF fontInfo( mFont );
-  setSceneRect( QRectF( transform().dx(), transform().dy(), fontInfo.width( mText ) + 2 * mMargin + 2 * pen().widthF(), fontInfo.ascent() + 2 * mMargin + 2 * pen().widthF() ) );
+  double textWidth = textWidthMM(mFont, mText);
+  double fontAscent = fontAscentMM(mFont);
+
+  setSceneRect( QRectF( transform().dx(), transform().dy(), textWidth + 2 * mMargin + 2 * pen().widthF() + 1, \
+			fontAscent + 2 * mMargin + 2 * pen().widthF() + 1) );
 }
 
 QFont QgsComposerLabel::font() const
 {
-  if ( mComposition ) //make pixel to point conversion to show correct point value in dialogs
-  {
-    double pointSize = mComposition->pointFontSize( mFont.pixelSize() );
-    QFont returnFont = mFont;
-    returnFont.setPointSize( pointSize );
-    return returnFont;
-  }
   return mFont;
 }