From 7edefe64ab75102ce137ab5266232a12462b5e87 Mon Sep 17 00:00:00 2001
From: stevehalasz <stevehalasz@c8812cc2-4d05-0410-92ff-de0c093fc19c>
Date: Thu, 20 Nov 2003 21:16:42 +0000
Subject: [PATCH] can display indexed color GeoTIFF with GDAL

git-svn-id: http://svn.osgeo.org/qgis/trunk@311 c8812cc2-4d05-0410-92ff-de0c093fc19c
---
 qgis/src/qgsrasterlayer.cpp | 92 +++++++++++++++++++++----------------
 1 file changed, 53 insertions(+), 39 deletions(-)

diff --git a/qgis/src/qgsrasterlayer.cpp b/qgis/src/qgsrasterlayer.cpp
index 81dc5d693a6..c65f2917020 100644
--- a/qgis/src/qgsrasterlayer.cpp
+++ b/qgis/src/qgsrasterlayer.cpp
@@ -22,61 +22,75 @@
 #include "qgsrect.h"
 #include "qgsrasterlayer.h"
 #include "gdal_priv.h"
-#include "qtiffio.h"
+//#include "qtiffio.h"
 
 QgsRasterLayer::QgsRasterLayer(QString path, QString baseName)
 :QgsMapLayer(RASTER, baseName, path)
 {
 	std::cout << "QgsRasterLayer::QgsRasterLayer()" << std::endl;
-	// test image handling using only Qt classes (don't use gdal)
 	
-	//~ GDALAllRegister();
-	//~ gdalDataset = (GDALDataset *) GDALOpen( path, GA_ReadOnly );
-	//~ std::cout << "Raster Count: " << gdalDataset->GetRasterCount() << std::endl;
+	GDALAllRegister();
+	gdalDataset = (GDALDataset *) GDALOpen( path, GA_ReadOnly );
+	std::cout << "Raster Count: " << gdalDataset->GetRasterCount() << std::endl;
 	
 }
 
 QgsRasterLayer::~QgsRasterLayer()
 {
+	GDALClose(gdalDataset);
 }
+
 void QgsRasterLayer::draw(QPainter * p, QgsRect * viewExtent, QgsCoordinateTransform * cXf)
 {
-	std::cout << "QgsRasterLayer::draw()" << std::endl;
+	/*
 	// init the tiff handler
-	qInitTiffIO();
-	std::cout << "Image source is " << source() << std::endl;
-	QImage *image = new QImage(source());
-	if(!image){
-		qWarning("Failed to load the image using path stored in source()");
-	}else{
-		qWarning("Loaded image");
+	//qInitTiffIO();
+	//std::cout << "Image source is " << source() << std::endl;
+	//QImage *image = new QImage(source());
+	//if(!image){
+	//	qWarning("Failed to load the image using path stored in source()");
+	//}else{
+	//	qWarning("Loaded image");
+	//}
+	//
+	//qWarning("Attempting to draw the image");
+	//p->drawImage(0, 0, *image);
+	//delete image;
+	*/
+	
+	std::cout << "QgsRasterLayer::draw()" << std::endl;
+	std::cout << "gdalDataset->GetRasterCount(): " << gdalDataset->GetRasterCount() << std::endl;
+	
+	// if there is more than one raster band they can be for red, green, blue, etc.
+	// so this loop doesn't make much sense right now
+	// only handling the case of 1 raster band that uses a palette
+	// to index the rgb color values
+	// this works for GeoTIFFs from:
+	// http://cugir.mannlib.cornell.edu/browse_map/quad_map.html
+	for (int i = 1; i <= gdalDataset->GetRasterCount(); i++) {
+		GDALRasterBand  *gdalBand = gdalDataset->GetRasterBand( i );
+
+		int nXSize = gdalBand->GetXSize();
+		int nYSize = gdalBand->GetYSize();
+		// read raster 1 line at a time
+		// display image at 0,0
+		for (int nYOff = 0; nYOff < nYSize; nYOff++) {
+			uint *scanline = (uint*) CPLMalloc(sizeof(uint)*nXSize);
+			CPLErr result = gdalBand->RasterIO( 
+					GF_Read, 0, nYOff, nXSize, 1, scanline, nXSize, 1, GDT_UInt32, 0, 0 );
+			
+			GDALColorTable *colorTable = gdalBand->GetColorTable();
+			
+			// print each point in scanline using color looked up in color table
+			for (int i = 0; i < nXSize; i++) {
+				const GDALColorEntry *colorEntry = GDALGetColorEntry (colorTable, scanline[i]);
+				p->setPen(QColor(colorEntry->c1, colorEntry->c2, colorEntry->c3));
+				p->drawPoint(i, nYOff);
+			}
+			
+			CPLFree(scanline);
+		}
 	}
-	//~ for (int i = 1; i <= gdalDataset->GetRasterCount(); i++) {
-		//~ GDALRasterBand  *gdalBand = gdalDataset->GetRasterBand( i );
-		//~ int xBlk;
-		//~ int yBlk;
-		//~ gdalBand->GetBlockSize(&xBlk, &yBlk);
-		//~ std::cout << "Block Size: " << xBlk << ", " << yBlk << std::endl;
-		//~ std::cout << "Raster Data Type: " << gdalBand->GetRasterDataType() << std::endl
-		//~ QImage image;
-		//~ bool good = image.
-		//~ /*
-		//~ std::cout << "Raster X, Y: : " << gdalBand->GetXSize() << ", "
-			//~ << gdalBand->GetYSize()  << std::endl;
-		//~ int *pafScanline = (int *) CPLMalloc(nXSize);
-		//~ gdalBand->RasterIO( GF_Read, 0, 0, nXSize, 1, pafScanline, nXSize, 1, GDT_UInt32, 0, 0 );
-		
-		//~ QImage image;
-		//~ bool good = image.loadFromData(reinterpret_cast <const uchar*> (pafScanline), nXSize);
-		//~ if(!good){
-			//~ qWarning("Unable to load image data from GDAL scan line");
-		//~ }
-		//~ CPLFree(pafScanline);
-		//~ */
-		qWarning("Attempting to draw the image");
-		p->drawImage(0, 0, *image);
-		delete image;
-//	}
 }
 
 //void QgsRasterLayer::identify(QgsRect * r)