bool QgsImageWarper::openSrcDSAndGetWarpOpt( const QString &input, const ResamplingMethod &resampling,
const GDALTransformerFunc &pfnTransform,
GDALDatasetH &hSrcDS, GDALWarpOptions *&psWarpOptions )
{
// Open input file
GDALAllRegister();
hSrcDS = GDALOpen( TO8F( input ), GA_ReadOnly );
if ( !hSrcDS )
return false;
// Setup warp options.
psWarpOptions = GDALCreateWarpOptions();
psWarpOptions->hSrcDS = hSrcDS;
psWarpOptions->nBandCount = GDALGetRasterCount( hSrcDS );
psWarpOptions->panSrcBands =
( int * ) CPLMalloc( sizeof( int ) * psWarpOptions->nBandCount );
psWarpOptions->panDstBands =
( int * ) CPLMalloc( sizeof( int ) * psWarpOptions->nBandCount );
for ( int i = 0; i < psWarpOptions->nBandCount; ++i )
{
psWarpOptions->panSrcBands[i] = i + 1;
psWarpOptions->panDstBands[i] = i + 1;
}
psWarpOptions->pfnProgress = GDALTermProgress;
psWarpOptions->pfnTransformer = pfnTransform;
psWarpOptions->eResampleAlg = GDALResampleAlg( resampling );
return true;
}
void QgsImageWarper::warp( const QString& input, const QString& output,
double& xOffset, double& yOffset,
ResamplingMethod resampling, bool useZeroAsTrans, const QString& compression )
{
// Open input file
GDALAllRegister();
GDALDatasetH hSrcDS = GDALOpen( QFile::encodeName( input ).constData(), GA_ReadOnly );
// Setup warp options.
GDALWarpOptions *psWarpOptions = GDALCreateWarpOptions();
psWarpOptions->hSrcDS = hSrcDS;
psWarpOptions->nBandCount = GDALGetRasterCount( hSrcDS );
psWarpOptions->panSrcBands =
( int * ) CPLMalloc( sizeof( int ) * psWarpOptions->nBandCount );
psWarpOptions->panDstBands =
( int * ) CPLMalloc( sizeof( int ) * psWarpOptions->nBandCount );
for ( int i = 0; i < psWarpOptions->nBandCount; ++i )
{
psWarpOptions->panSrcBands[i] = i + 1;
psWarpOptions->panDstBands[i] = i + 1;
}
psWarpOptions->pfnProgress = GDALTermProgress;
psWarpOptions->pfnTransformer = &QgsImageWarper::transform;
psWarpOptions->eResampleAlg = GDALResampleAlg( resampling );
// check the bounds for the warped raster
// order: upper right, lower right, lower left (y points down)
double x[] = { GDALGetRasterXSize( hSrcDS ), GDALGetRasterXSize( hSrcDS ), 0 };
double y[] = { 0, GDALGetRasterYSize( hSrcDS ), GDALGetRasterYSize( hSrcDS ) };
int s[] = { 0, 0, 0 };
TransformParameters tParam = { mAngle, 0, 0 };
transform( &tParam, FALSE, 3, x, y, NULL, s );
double minX = 0, minY = 0, maxX = 0, maxY = 0;
for ( int i = 0; i < 3; ++i )
{
minX = minX < x[i] ? minX : x[i];
minY = minY < y[i] ? minY : y[i];
maxX = maxX > x[i] ? maxX : x[i];
maxY = maxY > y[i] ? maxY : y[i];
}
int newXSize = int( maxX - minX ) + 1;
int newYSize = int( maxY - minY ) + 1;
xOffset = -minX;
yOffset = -minY;
tParam.x0 = xOffset;
tParam.y0 = yOffset;
psWarpOptions->pTransformerArg = &tParam;
// create the output file
GDALDriverH driver = GDALGetDriverByName( "GTiff" );
char **papszOptions = NULL;
papszOptions = CSLSetNameValue( papszOptions, "INIT_DEST", "NO_DATA" );
papszOptions = CSLSetNameValue( papszOptions, "COMPRESS", compression.toAscii() );
GDALDatasetH hDstDS =
GDALCreate( driver,
QFile::encodeName( output ).constData(), newXSize, newYSize,
GDALGetRasterCount( hSrcDS ),
GDALGetRasterDataType( GDALGetRasterBand( hSrcDS, 1 ) ),
papszOptions );
for ( int i = 0; i < GDALGetRasterCount( hSrcDS ); ++i )
{
GDALRasterBandH hSrcBand = GDALGetRasterBand( hSrcDS, i + 1 );
GDALRasterBandH hDstBand = GDALGetRasterBand( hDstDS, i + 1 );
GDALColorTableH cTable = GDALGetRasterColorTable( hSrcBand );
GDALSetRasterColorInterpretation( hDstBand, GDALGetRasterColorInterpretation( hSrcBand ) );
if ( cTable )
{
GDALSetRasterColorTable( hDstBand, cTable );
}
double noData = GDALGetRasterNoDataValue( hSrcBand, NULL );
if ( noData == -1e10 && useZeroAsTrans )
{
GDALSetRasterNoDataValue( hDstBand, 0 );
}
else
{
GDALSetRasterNoDataValue( hDstBand, noData );
}
}
psWarpOptions->hDstDS = hDstDS;
// Initialize and execute the warp operation.
GDALWarpOperation oOperation;
oOperation.Initialize( psWarpOptions );
oOperation.ChunkAndWarpImage( 0, 0, GDALGetRasterXSize( hDstDS ),
GDALGetRasterYSize( hDstDS ) );
GDALDestroyWarpOptions( psWarpOptions );
GDALClose( hSrcDS );
GDALClose( hDstDS );
}
