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ogr provider update: lazy determine extent (fixes #2752)
git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@13596 c8812cc2-4d05-0410-92ff-de0c093fc19c
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jef committed May 29, 2010
1 parent 82046b5 commit 8985c517e2ba0fbab7690706761ee4d4a731972a
Showing with 67 additions and 14 deletions.
  1. +67 −14 src/providers/ogr/qgsogrprovider.cpp
@@ -26,6 +26,8 @@ email : sherman at mrcc.com
#include <cpl_error.h>
#include <cpl_conv.h>

#include <limits>

#include <QtDebug>
#include <QFile>
#include <QDir>
@@ -176,8 +178,6 @@ QgsOgrProvider::QgsOgrProvider( QString const & uri )
ogrOrigLayer = OGR_DS_GetLayerByName( ogrDataSource, mLayerName.toLocal8Bit().data() );
}

extent_ = calloc( sizeof( OGREnvelope ), 1 );

ogrLayer = ogrOrigLayer;
setSubsetString( mSubsetString );
}
@@ -205,8 +205,13 @@ QgsOgrProvider::~QgsOgrProvider()

OGR_DS_Destroy( ogrDataSource );
ogrDataSource = 0;
free( extent_ );
extent_ = 0;

if ( extent_ )
{
free( extent_ );
extent_ = 0;
}

if ( mSelectionRectangle )
{
OGR_G_DestroyGeometry( mSelectionRectangle );
@@ -273,19 +278,17 @@ bool QgsOgrProvider::setSubsetString( QString theSQL )
// TODO: This can be expensive, do we really need it!
recalculateFeatureCount();

// get the extent_ (envelope) of the layer
QgsDebugMsg( "Starting get extent" );

// TODO: This can be expensive, do we really need it!
OGR_L_GetExtent( ogrLayer, ( OGREnvelope * ) extent_, true );

QgsDebugMsg( "Finished get extent" );

// check the validity of the layer
QgsDebugMsg( "checking validity" );
loadFields();
QgsDebugMsg( "Done checking validity" );

if ( extent_ )
{
free( extent_ );
extent_ = 0;
}

return true;
}

@@ -607,7 +610,53 @@ unsigned char * QgsOgrProvider::getGeometryPointer( OGRFeatureH fet )

QgsRectangle QgsOgrProvider::extent()
{
OGREnvelope *ext = ( OGREnvelope * ) extent_;
if ( !extent_ )
{
extent_ = calloc( sizeof( OGREnvelope ), 1 );

// get the extent_ (envelope) of the layer
QgsDebugMsg( "Starting get extent" );

// TODO: This can be expensive, do we really need it!
if ( ogrLayer == ogrOrigLayer )
{
OGR_L_GetExtent( ogrLayer, ( OGREnvelope * ) extent_, true );
}
else
{
OGREnvelope *bb = static_cast<OGREnvelope*>( extent_ );

bb->MinX = std::numeric_limits<double>::max();
bb->MinY = std::numeric_limits<double>::max();
bb->MaxX = -std::numeric_limits<double>::max();
bb->MaxY = -std::numeric_limits<double>::max();

OGRFeatureH f;

OGR_L_ResetReading( ogrLayer );
while (( f = OGR_L_GetNextFeature( ogrLayer ) ) )
{
OGRGeometryH g = OGR_F_GetGeometryRef( f );
if ( g )
{
OGREnvelope env;
OGR_G_GetEnvelope( g, &env );

if ( env.MinX < bb->MinX ) bb->MinX = env.MinX;
if ( env.MinY < bb->MinY ) bb->MinY = env.MinY;
if ( env.MaxX > bb->MaxX ) bb->MaxX = env.MaxX;
if ( env.MaxY > bb->MaxY ) bb->MaxY = env.MaxY;
}

OGR_F_Destroy( f );
}
OGR_L_ResetReading( ogrLayer );
}

QgsDebugMsg( "Finished get extent" );
}

OGREnvelope *ext = static_cast<OGREnvelope *>( extent_ );
mExtentRect.set( ext->MinX, ext->MinY, ext->MaxX, ext->MaxY );
return mExtentRect;
}
@@ -999,7 +1048,11 @@ bool QgsOgrProvider::deleteFeatures( const QgsFeatureIds & id )

recalculateFeatureCount();

OGR_L_GetExtent( ogrOrigLayer, ( OGREnvelope * ) extent_, true );
if ( extent_ )
{
free( extent_ );
extent_ = 0;
}

return returnvalue;
}

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