Added raster renderer interface and test implementation for paletted rasters

Author: mhugent

src/core/raster/qgspalettedrasterrenderer.cpp

@@ -0,0 +1,48 @@
+#include "qgspalettedrasterrenderer.h"
+#include "qgsrasterviewport.h"
+#include <QColor>
+#include <QImage>
+#include <QPainter>
+
+QgsPalettedRasterRenderer::QgsPalettedRasterRenderer( QgsRasterDataProvider* provider, int bandNumber, QColor* colorArray, int nColors ):
+  QgsRasterRenderer( provider ), mBandNumber( bandNumber), mColors( colorArray ), mNColors( nColors )
+{
+}
+
+QgsPalettedRasterRenderer::~QgsPalettedRasterRenderer()
+{
+  delete[] mColors;
+}
+
+void QgsPalettedRasterRenderer::draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel )
+{
+  if( !p || !mProvider || !viewPort || !theQgsMapToPixel )
+  {
+    return;
+  }
+
+  //read data from provider
+  int typeSize = mProvider->dataTypeSize( mBandNumber ) / 8;
+  QgsRasterDataProvider::DataType rasterType = (QgsRasterDataProvider::DataType)mProvider->dataType( mBandNumber );
+  void* rasterData = VSIMalloc( typeSize * viewPort->drawableAreaXDim *  viewPort->drawableAreaYDim);
+  mProvider->readBlock( mBandNumber, viewPort->mDrawnExtent, viewPort->drawableAreaXDim, viewPort->drawableAreaYDim,
+             viewPort->mSrcCRS, viewPort->mDestCRS, rasterData );
+  int currentRasterPos = 0;
+
+  //raster image
+  QImage img( viewPort->drawableAreaXDim, viewPort->drawableAreaYDim, QImage::Format_ARGB32_Premultiplied );
+  QRgb* imageScanLine = 0;
+
+  for( int i = 0; i < viewPort->drawableAreaYDim; ++i )
+  {
+    imageScanLine = ( QRgb* )( img.scanLine( i ) );
+    for( int j = 0; j < viewPort->drawableAreaXDim; ++j )
+    {
+      int val = readValue( rasterData, rasterType, currentRasterPos );
+      imageScanLine[j] = mColors[ val ].rgba();
+      ++currentRasterPos;
+    }
+  }
+  CPLFree( rasterData );
+  p->drawImage( QPointF( viewPort->topLeftPoint.x(), viewPort->topLeftPoint.y() ), img );
+}

src/core/raster/qgspalettedrasterrenderer.h

@@ -0,0 +1,24 @@
+#ifndef QGSPALETTEDRASTERRENDERER_H
+#define QGSPALETTEDRASTERRENDERER_H
+
+#include "qgsrasterrenderer.h"
+
+class QColor;
+
+class QgsPalettedRasterRenderer: public QgsRasterRenderer
+{
+  public:
+    /**Renderer owns color array*/
+    QgsPalettedRasterRenderer( QgsRasterDataProvider* provider, int bandNumber, QColor* colorArray, int nColors );
+    ~QgsPalettedRasterRenderer();
+    void draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel );
+
+  private:
+    int mBandNumber;
+    /**Color array*/
+    QColor* mColors;
+    /**Number of colors*/
+    int mNColors;
+};
+
+#endif // QGSPALETTEDRASTERRENDERER_H

src/core/raster/qgsrasterrenderer.cpp

@@ -0,0 +1,9 @@
+#include "qgsrasterrenderer.h"
+
+QgsRasterRenderer::QgsRasterRenderer( QgsRasterDataProvider* provider ): mProvider( provider )
+{
+}
+
+QgsRasterRenderer::~QgsRasterRenderer()
+{
+}

src/core/raster/qgsrasterrenderer.h

@@ -0,0 +1,66 @@
+#ifndef QGSRASTERRENDERER_H
+#define QGSRASTERRENDERER_H
+
+#include "qgsrasterdataprovider.h"
+
+class QPainter;
+class QgsMapToPixel;
+class QgsRasterViewPort;
+
+class QgsRasterRenderer
+{
+  public:
+    QgsRasterRenderer( QgsRasterDataProvider* provider );
+    virtual ~QgsRasterRenderer();
+    virtual void draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel ) = 0;
+
+  protected:
+    inline double readValue( void *data, QgsRasterDataProvider::DataType type, int index );
+
+    QgsRasterDataProvider* mProvider;
+};
+
+inline double QgsRasterRenderer::readValue( void *data, QgsRasterDataProvider::DataType type, int index )
+{
+  if( !mProvider )
+  {
+    return 0;
+  }
+
+  if( !data )
+  {
+    return mProvider->noDataValue();
+  }
+
+  switch ( type )
+  {
+    case QgsRasterDataProvider::Byte:
+      return ( double )(( GByte * )data )[index];
+      break;
+    case QgsRasterDataProvider::UInt16:
+      return ( double )(( GUInt16 * )data )[index];
+      break;
+    case QgsRasterDataProvider::Int16:
+      return ( double )(( GInt16 * )data )[index];
+      break;
+    case QgsRasterDataProvider::UInt32:
+      return ( double )(( GUInt32 * )data )[index];
+      break;
+    case QgsRasterDataProvider::Int32:
+      return ( double )(( GInt32 * )data )[index];
+      break;
+    case QgsRasterDataProvider::Float32:
+      return ( double )(( float * )data )[index];
+      break;
+    case QgsRasterDataProvider::Float64:
+      return ( double )(( double * )data )[index];
+      break;
+    default:
+      //QgsMessageLog::logMessage( tr( "GDAL data type %1 is not supported" ).arg( type ), tr( "Raster" ) );
+      break;
+  }
+
+  return mProvider->noDataValue();
+}
+
+#endif // QGSRASTERRENDERER_H