Several WMS-related improvements:

* Better bounding-box checking on legacy WMS servers - JPL World Map Service works again.
* Providers can now expose the last error encountered by the provider.  Only WMS returns useful information though.
* Error display is now handled by the QgsMapCanvas not the QgsWmsProvider - this frees QgsWmsProvider from a dependency on the GUI being available.
* For map redraws, QApplication::setOverrideCursor and QApplication::restoreOverrideCursor are now handled by the QgsMapCanvas not the QgisApp - this helps stop error message popups (via QMessageBox) from suffering from the "hourglass" cursor appearing not the "pointer".
* Consective WMS operations do not fail any more - the "url" variable was being appended to, not cleared before each draw.



git-svn-id: http://svn.osgeo.org/qgis/trunk@4907 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/core/qgsrasterdataprovider.h

@@ -87,7 +87,23 @@ class QgsRasterDataProvider : public QgsDataProvider
      */
     virtual QString getMetadata() = 0;
 
-
+    /**
+     * If an operation returns 0 (e.g. draw()), this function
+     * returns the text of the error associated with the failure.
+     * Interactive users of this provider can then, for example,
+     * call a QMessageBox to display the contents.
+     */
+    virtual QString errorCaptionString() = 0;
+
+    /**
+     * If an operation returns 0 (e.g. draw()), this function
+     * returns the text of the error associated with the failure.
+     * Interactive users of this provider can then, for example,
+     * call a QMessageBox to display the contents.
+     */
+    virtual QString errorString() = 0;
+
+
 protected:
 
 };

src/gui/qgisapp.cpp

@@ -1692,7 +1692,8 @@ void QgisApp::addLayer()
 bool QgisApp::addLayer(QFileInfo const & vectorFile)
 {
   // let the user know we're going to possibly be taking a while
-  QApplication::setOverrideCursor(Qt::WaitCursor);
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
 
   mMapCanvas->freeze();         // XXX why do we do this?
 
@@ -1732,7 +1733,8 @@ bool QgisApp::addLayer(QFileInfo const & vectorFile)
     if ( ! renderer )
     {
       mMapCanvas->freeze(false);
-      QApplication::restoreOverrideCursor();
+// Let render() do its own cursor management
+//      QApplication::restoreOverrideCursor();
 
       // XXX should we also delete the layer?
 
@@ -1784,7 +1786,9 @@ bool QgisApp::addLayer(QFileInfo const & vectorFile)
     delete layer;
 
     mMapCanvas->freeze(false);
-    QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//    QApplication::restoreOverrideCursor();
 
     return false;
   }
@@ -1800,7 +1804,8 @@ bool QgisApp::addLayer(QFileInfo const & vectorFile)
                               //                 the layer is intially added
   mMapCanvas->update();
 
-  QApplication::restoreOverrideCursor();
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
 
   statusBar()->message(mMapCanvas->extent().stringRep(2));
 
@@ -1822,8 +1827,8 @@ bool QgisApp::addLayer(QStringList const &theLayerQStringList, const QString& en
 {
   mMapCanvas->freeze();
 
-  QApplication::setOverrideCursor(Qt::WaitCursor);
-
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
 
   for ( QStringList::ConstIterator it = theLayerQStringList.begin();
       it != theLayerQStringList.end();
@@ -1846,7 +1851,9 @@ bool QgisApp::addLayer(QStringList const &theLayerQStringList, const QString& en
     if ( ! layer )
     {
       mMapCanvas->freeze(false);
-      QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//      QApplication::restoreOverrideCursor();
 
       // XXX insert meaningful whine to the user here
       return false;
@@ -1868,7 +1875,9 @@ bool QgisApp::addLayer(QStringList const &theLayerQStringList, const QString& en
       if ( ! renderer )
       {
         mMapCanvas->freeze(false);
-        QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//        QApplication::restoreOverrideCursor();
 
         // XXX insert meaningful whine to the user here
         return false;
@@ -1937,7 +1946,10 @@ bool QgisApp::addLayer(QStringList const &theLayerQStringList, const QString& en
   // [gsherman]
   mMapCanvas->render();
   mMapCanvas->update();
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
+
   statusBar()->message(mMapCanvas->extent().stringRep(2));
 
 
@@ -1975,7 +1987,8 @@ void QgisApp::addDatabaseLayer()
 
   if (dbs->exec())
   {
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+// Let render() do its own cursor management
+//    QApplication::setOverrideCursor(Qt::WaitCursor);
 
 
     // repaint the canvas if it was covered by the dialog
@@ -2056,7 +2069,10 @@ void QgisApp::addDatabaseLayer()
   // [gsherman]
   mMapCanvas->render();
   mMapCanvas->update();
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
+
 } // QgisApp::addDatabaseLayer()
 #endif
 
@@ -4719,7 +4735,10 @@ QString QgisApp::activeLayerSource()
 void QgisApp::addVectorLayer(QString vectorLayerPath, QString baseName, QString providerKey)
 {
   mMapCanvas->freeze();
-  QApplication::setOverrideCursor(Qt::WaitCursor);
+
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
+
   // create the layer
   QgsVectorLayer *layer;
   /* Eliminate the need to instantiate the layer based on provider type.
@@ -4796,7 +4815,9 @@ void QgisApp::addVectorLayer(QString vectorLayerPath, QString baseName, QString
   // [gsherman]
   mMapCanvas->render();
   mMapCanvas->update();
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
 
 } // QgisApp::addVectorLayer
 
@@ -4805,7 +4826,10 @@ void QgisApp::addVectorLayer(QString vectorLayerPath, QString baseName, QString
 void QgisApp::addMapLayer(QgsMapLayer *theMapLayer)
 {
   mMapCanvas->freeze();
-  QApplication::setOverrideCursor(Qt::WaitCursor);
+
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
+
   if(theMapLayer->isValid())
   {
     // Register this layer with the layers registry
@@ -4838,7 +4862,9 @@ void QgisApp::addMapLayer(QgsMapLayer *theMapLayer)
   // [gsherman]
   mMapCanvas->render();
   mMapCanvas->update();
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
 
 }
 
@@ -5476,7 +5502,10 @@ bool QgisApp::addRasterLayer(QFileInfo const & rasterFile, bool guiWarning)
   if (!addRasterLayer(layer))
   {
     mMapCanvas->freeze(false);
-    QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//    QApplication::restoreOverrideCursor();
+
     if(guiWarning)
     {
       // don't show the gui warning (probably because we are loading from command line)
@@ -5491,7 +5520,10 @@ bool QgisApp::addRasterLayer(QFileInfo const & rasterFile, bool guiWarning)
     statusBar()->message(mMapCanvas->extent().stringRep(2));
     mMapCanvas->freeze(false);
     mOverviewCanvas->freeze(false);
-    QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//    QApplication::restoreOverrideCursor();
+
     return true;
   }
 
@@ -5522,7 +5554,10 @@ void QgisApp::addRasterLayer(QString const & rasterLayerPath,
 #endif
 
   mMapCanvas->freeze();
-  QApplication::setOverrideCursor(Qt::WaitCursor);
+
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
+
   // create the layer
   QgsRasterLayer *layer;
   /* Eliminate the need to instantiate the layer based on provider type.
@@ -5605,7 +5640,9 @@ void QgisApp::addRasterLayer(QString const & rasterLayerPath,
   // [gsherman]
   mMapCanvas->render();
   mMapCanvas->update();
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
 
 } // QgisApp::addRasterLayer
 
@@ -5627,7 +5664,9 @@ bool QgisApp::addRasterLayer(QStringList const &theFileNameQStringList, bool gui
   mMapCanvas->freeze(true);
   mOverviewCanvas->freeze(true);
 
-  QApplication::setOverrideCursor(Qt::WaitCursor);
+// Let render() do its own cursor management
+//  QApplication::setOverrideCursor(Qt::WaitCursor);
+
   // this is messy since some files in the list may be rasters and others may
   // be ogr layers. We'll set returnValue to false if one or more layers fail
   // to load.
@@ -5682,7 +5721,9 @@ bool QgisApp::addRasterLayer(QStringList const &theFileNameQStringList, bool gui
   statusBar()->message(mMapCanvas->extent().stringRep(2));
   mMapCanvas->freeze(false);
   mOverviewCanvas->freeze(false);
-  QApplication::restoreOverrideCursor();
+
+// Let render() do its own cursor management
+//  QApplication::restoreOverrideCursor();
 
   return returnValue;
 

src/gui/qgsmapcanvas.cpp

@@ -80,7 +80,7 @@ email                : sherman at mrcc.com
 #include <qcursor.h>
 
 #include <QRubberBand>
-
+#include <QApplication>
 
 #include "qgis.h"
 #include "qgsrect.h"
@@ -558,6 +558,10 @@ void QgsMapCanvas::render(QPaintDevice * theQPaintDevice)
   {
     if (!mCanvasProperties->drawing)
     {
+
+      // Tell the user we're going to be a while
+      QApplication::setOverrideCursor(Qt::WaitCursor);
+
       mCanvasProperties->drawing = true;
       QPainter *paint = new QPainter();
 
@@ -747,10 +751,16 @@ void QgsMapCanvas::render(QPaintDevice * theQPaintDevice)
                 // Now do the call to the layer that actually does
                 // the rendering work!
                 //
-                ml->draw(paint, &r1, mCanvasProperties->coordXForm, this);
+                if (!ml->draw(paint, &r1, mCanvasProperties->coordXForm, this))
+                {
+                  showError(ml);
+                }
                 if (split)
                 {
-                  ml->draw(paint, &r2,mCanvasProperties->coordXForm, this);
+                  if (!ml->draw(paint, &r2, mCanvasProperties->coordXForm, this))
+                  {
+                    showError(ml);
+                  }
                 }
               }
 #ifdef QGISDEBUG
@@ -922,6 +932,9 @@ void QgsMapCanvas::render(QPaintDevice * theQPaintDevice)
       paint->end();
       mCanvasProperties->drawing = false;
       delete paint;
+
+      // Tell the user we've finished going to be a while
+      QApplication::restoreOverrideCursor();
     }
     mCanvasProperties->dirty = false;
 
@@ -3345,3 +3358,17 @@ QgsPoint QgsMapCanvas::maybeInversePoint(QgsPoint point, const char whenmsg[])
   }
   return point;
 }
+
+
+void QgsMapCanvas::showError(QgsMapLayer * mapLayer)
+{
+  QMessageBox::warning(
+    this,
+    mapLayer->errorCaptionString(),
+    tr("Could not draw") + " " + mapLayer->name() + " " + tr("because") + ":\n" +
+      mapLayer->errorCaptionString()
+  );
+
+}
+
+// ENDS

src/gui/qgsmapcanvas.h

@@ -339,6 +339,9 @@ public slots:
      */
     QgsMapCanvas();
 
+    //! show whatever error is exposed by the QgsMapLayer.
+    void showError(QgsMapLayer * mapLayer);
+
     /**
        List to store the points of digitised lines and polygons
 

src/gui/qgsmaplayer.cpp

@@ -153,7 +153,7 @@ void QgsMapLayer::draw(QPainter *, QgsRect * viewExtent, int yTransform)
     //  std::cout << "In QgsMapLayer::draw" << std::endl;
 }
 
-void QgsMapLayer::draw(QPainter *, QgsRect *, QgsMapToPixel *,QPaintDevice * )
+bool QgsMapLayer::draw(QPainter *, QgsRect *, QgsMapToPixel *,QPaintDevice * )
 {
     //  std::cout << "In QgsMapLayer::draw" << std::endl;
 }
@@ -499,6 +499,16 @@ std::vector<QgsField> const & QgsMapLayer::fields() const
     return bogus;
 } // QgsMapLayer::fields()
 
+QString QgsMapLayer::errorCaptionString()
+{
+  return QString();
+}
+
+QString QgsMapLayer::errorString()
+{
+  return QString();
+}
+
 void QgsMapLayer::connectNotify( const char * signal )
 {
 #ifdef QGISDEBUG

src/gui/qgsmaplayer.h

@@ -99,7 +99,10 @@ class QgsMapLayer : public QObject
 
 
     virtual void draw(QPainter *, QgsRect *, int);
-    virtual void draw(QPainter *, QgsRect *, QgsMapToPixel * ,QPaintDevice *);
+
+    //! Returns FALSE if an error occurred during drawing
+    virtual bool draw(QPainter *, QgsRect *, QgsMapToPixel *, QPaintDevice *);
+
     virtual void drawLabels(QPainter *, QgsRect *, QgsMapToPixel * ,QPaintDevice *);
     /*! Identify the feature(s) in this layer that are contained in the search rectangle
      */
@@ -284,6 +287,25 @@ class QgsMapLayer : public QObject
 
     /** \brief accessor for transparency level.  */
     virtual unsigned int getTransparency()=0;
+
+
+    /**
+     * If an operation returns 0 (e.g. draw()), this function
+     * returns the text of the error associated with the failure.
+     * Interactive users of this provider can then, for example,
+     * call a QMessageBox to display the contents.
+     */
+    QString errorCaptionString();
+
+    /**
+     * If an operation returns 0 (e.g. draw()), this function
+     * returns the text of the error associated with the failure.
+     * Interactive users of this provider can then, for example,
+     * call a QMessageBox to display the contents.
+     */
+    QString errorString();
+
+
 public  slots:
     /** \brief Mutator for transparency level. Should be between 0 and 255 */
     virtual void setTransparency(int)=0; //