Use a DPI parameter in the WMS request. This allows printing with QGIS from QGIS mapserver (and is ignored by the other WMS servers)

git-svn-id: http://svn.osgeo.org/qgis/trunk@10885 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: mhugent

python/core/qgsrasterdataprovider.sip

@@ -120,6 +120,14 @@ public:
      */
     virtual QString lastError() = 0;
 
+      /**Returns the dpi of the output device.
+      @note: this method was added in version 1.2*/
+    int dpi();
+
+    /**Sets the output device resolution.
+      @note: this method was added in version 1.2*/
+    void setDpi(int dpi);
+
 
 protected:
 

src/core/qgsrasterdataprovider.cpp

@@ -19,13 +19,13 @@
 #include "qgsrasterdataprovider.h"
 #include "qgslogger.h"
 
-QgsRasterDataProvider::QgsRasterDataProvider()
+QgsRasterDataProvider::QgsRasterDataProvider(): mDpi(-1)
 {
 }
 
 
 QgsRasterDataProvider::QgsRasterDataProvider( QString const & uri )
-    : QgsDataProvider( uri )
+    : QgsDataProvider( uri ), mDpi(-1)
 {
 }
 

src/core/qgsrasterdataprovider.h

@@ -152,8 +152,20 @@ class CORE_EXPORT QgsRasterDataProvider : public QgsDataProvider
      */
     virtual QString lastError() = 0;
 
+    /**Returns the dpi of the output device.
+      @note: this method was added in version 1.2*/
+    int dpi() const {return mDpi;}
+
+    /**Sets the output device resolution.
+      @note: this method was added in version 1.2*/
+    void setDpi(int dpi){mDpi = dpi;}
+
 
   protected:
+    /**Dots per intch. Extended WMS (e.g. QGIS mapserver) support DPI dependent output and therefore
+  are suited for printing. A value of -1 means it has not been set
+  @note: this member has been added in version 1.2*/
+    int mDpi;
 
 };
 

src/providers/wms/qgswmsprovider.cpp

@@ -454,6 +454,12 @@ QImage* QgsWmsProvider::draw( QgsRectangle  const & viewExtent, int pixelWidth,
   url += "&";
   url += "FORMAT=" + imageMimeType;
 
+  //DPI parameter is accepted by QGIS mapserver (and ignored by the other WMS servers)
+  if(mDpi != -1)
+  {
+    url += "&DPI=" + QString::number(mDpi);
+  }
+
   //MH: jpeg does not support transparency and some servers complain if jpg and transparent=true
   if ( !imageMimeType.contains( "jpeg", Qt::CaseInsensitive ) && !imageMimeType.contains( "jpg", Qt::CaseInsensitive ) )
   {