From a7c67fe2870ea9583800503ea244ca10ba98f5c8 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 4 Oct 2007 08:54:41 +0000
Subject: [PATCH] From Trajce Nikolov, added support for extract a region for
 geospatial imagery

---
 src/osgPlugins/gdal/DataSetLayer.cpp     | 44 +++++++++++++++++++-----
 src/osgPlugins/gdal/DataSetLayer.h       |  6 ++++
 src/osgPlugins/gdal/ReaderWriterGDAL.cpp |  1 +
 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/src/osgPlugins/gdal/DataSetLayer.cpp b/src/osgPlugins/gdal/DataSetLayer.cpp
index 67440e46b..2658f15cb 100644
--- a/src/osgPlugins/gdal/DataSetLayer.cpp
+++ b/src/osgPlugins/gdal/DataSetLayer.cpp
@@ -20,21 +20,23 @@
 #include <gdalwarper.h>
 #include <ogr_spatialref.h>
 
+#include <osgDB/ImageOptions>
+
 using namespace GDALPlugin;
 
 DataSetLayer::DataSetLayer():
-    _dataset(0)
+_dataset(0), _gdalReader(0)
 {
 }
 
 DataSetLayer::DataSetLayer(const std::string& fileName):
-    _dataset(0)
+_dataset(0), _gdalReader(0)
 {
     openFile(fileName);
 }
 
 DataSetLayer::DataSetLayer(const DataSetLayer& dataSetLayer,const osg::CopyOp& copyop):
-    ProxyLayer(dataSetLayer)
+ProxyLayer(dataSetLayer), _gdalReader(dataSetLayer._gdalReader)
 {
     if (dataSetLayer._dataset) open();
 }
@@ -49,9 +51,9 @@ void DataSetLayer::open()
     if (_dataset) return;
 
     if (getFileName().empty()) return;
-    
+
     _dataset = static_cast<GDALDataset*>(GDALOpen(getFileName().c_str(),GA_ReadOnly));
-    
+
     setUpLocator();
 }
 
@@ -60,7 +62,7 @@ void DataSetLayer::close()
     if (_dataset)
     {
         GDALClose(static_cast<GDALDatasetH>(_dataset));
-        
+
         _dataset = 0;
     }
 }
@@ -79,15 +81,39 @@ osgTerrain::ImageLayer* DataSetLayer::extractImageLayer(unsigned int sourceMinX,
 {
     if (!_dataset || sourceMaxX<sourceMinX || sourceMaxY<sourceMinY) return 0;
 
-    osg::notify(osg::NOTICE)<<"DataSetLayer::extractImageLayer("<<sourceMinX<<", "<<sourceMinY<<", "<<sourceMaxX<<", "<<sourceMaxY<<", target:"<<targetWidth<<", "<<targetHeight<<") not yet implemented"<<std::endl;
+    if (!_gdalReader) return 0;
 
-    return 0;
+    osg::ref_ptr<osgDB::ImageOptions> imageOptions = new osgDB::ImageOptions;
+    imageOptions->_sourceImageWindowMode = osgDB::ImageOptions::PIXEL_WINDOW;
+    imageOptions->_sourcePixelWindow.windowX = sourceMinX;
+    imageOptions->_sourcePixelWindow.windowY = sourceMinY;
+    imageOptions->_sourcePixelWindow.windowWidth = sourceMaxX-sourceMinX;
+    imageOptions->_sourcePixelWindow.windowHeight = sourceMaxY-sourceMinY;
+    imageOptions->_destinationPixelWindow.windowX = 0;
+    imageOptions->_destinationPixelWindow.windowY = 0;
+    imageOptions->_destinationPixelWindow.windowWidth = targetWidth;
+    imageOptions->_destinationPixelWindow.windowHeight = targetHeight;
+
+    osgDB::ReaderWriter::ReadResult result = _gdalReader->readImage(getFileName(),imageOptions.get());
+    osg::Image* image = result.getImage();
+    if (!image) return 0;
+
+    osgTerrain::ImageLayer* layer = new osgTerrain::ImageLayer;
+    layer->setFileName(getFileName());
+    layer->setImage(image);
+
+    return layer;
+}
+
+void DataSetLayer::setGdalReader(const osgDB::ReaderWriter* rw)
+{
+    _gdalReader = const_cast<osgDB::ReaderWriter*>(rw);
 }
 
 void DataSetLayer::setUpLocator()
 {
     if (!isOpen()) return;
-    
+
     const char* pszSourceSRS = _dataset->GetProjectionRef();
     if (!pszSourceSRS || strlen(pszSourceSRS)==0) pszSourceSRS = _dataset->GetGCPProjection();
 
diff --git a/src/osgPlugins/gdal/DataSetLayer.h b/src/osgPlugins/gdal/DataSetLayer.h
index f7ff1c358..d27995d10 100644
--- a/src/osgPlugins/gdal/DataSetLayer.h
+++ b/src/osgPlugins/gdal/DataSetLayer.h
@@ -15,6 +15,7 @@
 #define DATASETLAYER 1
 
 #include <osgTerrain/Layer>
+#include <osgDB/ReaderWriter>
 
 #include <gdal_priv.h>
 
@@ -45,6 +46,8 @@ class DataSetLayer : public osgTerrain::ProxyLayer
 
         virtual osgTerrain::ImageLayer* extractImageLayer(unsigned int sourceMinX, unsigned int sourceMinY, unsigned int sourceMaxX, unsigned int sourceMaxY, unsigned int targetWidth=0, unsigned int targetHeight=0);
 
+        void setGdalReader(const osgDB::ReaderWriter* rw);
+
     protected:
     
         virtual ~DataSetLayer();
@@ -53,6 +56,9 @@ class DataSetLayer : public osgTerrain::ProxyLayer
     
         GDALDataset* _dataset;
 
+        osgDB::ReaderWriter* _gdalReader;
+
+
 };
 
 }
diff --git a/src/osgPlugins/gdal/ReaderWriterGDAL.cpp b/src/osgPlugins/gdal/ReaderWriterGDAL.cpp
index 7ac1f59b6..6e161f7bf 100644
--- a/src/osgPlugins/gdal/ReaderWriterGDAL.cpp
+++ b/src/osgPlugins/gdal/ReaderWriterGDAL.cpp
@@ -53,6 +53,7 @@ class ReaderWriterGDAL : public osgDB::ReaderWriter
 
             // open a DataSetLayer.
             osg::ref_ptr<GDALPlugin::DataSetLayer> dataset = new GDALPlugin::DataSetLayer(fileName);
+            dataset->setGdalReader(this);
             
             if (dataset->isOpen()) return dataset.release();