Patch qgis#878 for PrintComposer SVG Export from Steven Bell with con…

…ditional compilation directives added to use QSvgGenerator for Qt4.3 or greater while continuing to use Q3Picture for Qt 4.2 or lower.

git-svn-id: http://svn.osgeo.org/qgis/trunk@8264 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/app/composer/qgscomposer.cpp

@@ -37,7 +37,11 @@
 #include <QSettings>
 #include <QIcon>
 #include <QPixmap>
+#if QT_VERSION < 0x040300
 #include <Q3Picture>
+#else
+#include <QSvgGenerator>
+#endif
 #include <QToolBar>
 #include <QImageWriter>
 #include <QCheckBox>
@@ -773,9 +777,6 @@ QRectF renderArea(0,0,(mComposition->paperWidth() * mComposition->scale()),(mCom
 void QgsComposer::on_mActionExportAsSVG_activated(void)
 {
 
-// QT 4 QPicture does not support export to SVG, so we're still using Q3Picture.
-// When QGIS moves to Qt 4.3, we can use QSvgGenerator instead.
-
   QString myQSettingsLabel = "/UI/displaySVGWarning";
   QSettings myQSettings;
 
@@ -791,10 +792,16 @@ void QgsComposer::on_mActionExportAsSVG_activated(void)
     m->setCheckBoxQSettingsLabel(myQSettingsLabel);
     m->setMessageAsHtml(tr("<p>The SVG export function in Qgis has several "
                            "problems due to bugs and deficiencies in the "
+#if QT_VERSION < 0x040300
                            "Qt4 svg code. Of note, text does not "
                            "appear in the SVG file and there are problems "
                            "with the map bounding box clipping other items "
                            "such as the legend or scale bar.</p>"
+#else
+                           "Qt4 svg code. In particular, there are problems "
+                           "with layers not being clipped to the map"
+                           "bounding box.</p>"
+#endif
                            "If you require a vector-based output file from "
                            "Qgis it is suggested that you try printing "
                            "to PostScript if the SVG output is not "
@@ -822,20 +829,30 @@ void QgsComposer::on_mActionExportAsSVG_activated(void)
   mView->setScene(0);//don't redraw the scene on the display while we render
   mComposition->setPlotStyle ( QgsComposition::Print );
 
+#if QT_VERSION < 0x040300
   Q3Picture pic;
   QPainter p(&pic);
   QRectF renderArea(0,0, (mComposition->paperWidth() * mComposition->scale()), (mComposition->paperHeight() * mComposition->scale()) );
-
+#else
+  QSvgGenerator generator;
+  generator.setFileName(myOutputFileNameQString);
+  generator.setSize(QSize( (int)mComposition->paperWidth(), (int)mComposition->paperHeight() ));
+  generator.setResolution((int)(mComposition->resolution() / 25.4)); //because the rendering is done in mm, convert the dpi
+
+  QPainter p(&generator);
+  QRectF renderArea(0,0, mComposition->paperWidth(), mComposition->paperHeight());
+#endif
   mComposition->canvas()->render(&p, renderArea);
   p.end();
 
   mComposition->setPlotStyle ( QgsComposition::Preview );
   mView->setScene(mComposition->canvas()); //now that we're done, set the view to show the scene again
 
+#if QT_VERSION < 0x040300
   QRect br = pic.boundingRect();
 
   pic.save ( myOutputFileNameQString, "svg" );
-
+#endif
 }