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Convenience API call to create empty raster file

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This commit is contained in:
Martin Dobias 2017-01-19 13:23:15 +08:00
parent 15cd8331ac
commit 7b27079de9
4 changed files with 61 additions and 0 deletions
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10
python/core/raster/qgsrasterfilewriter.sip
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@ -29,6 +29,16 @@ class QgsRasterFileWriter
QgsRasterFileWriter( const QString& outputUrl );
/** Create a raster file with one band without initializing the pixel data.
* @note Does not work with tiled mode enabled.
* @returns true when the raster has been created successfully
* @note added in QGIS 3.0
*/
bool createOneBandRaster( Qgis::DataType dataType,
int width, int height,
const QgsRectangle& extent,
const QgsCoordinateReferenceSystem& crs );
/** Write raster file
@param pipe raster pipe
@param nCols number of output columns

15
src/core/raster/qgsrasterfilewriter.cpp
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@ -29,6 +29,21 @@
#include <QTextStream>
#include <QMessageBox>
bool QgsRasterFileWriter::createOneBandRaster( Qgis::DataType dataType, int width, int height, const QgsRectangle &extent, const QgsCoordinateReferenceSystem &crs )
{
if ( mTiledMode )
return false; // does not make sense with tiled mode
double pixelSize;
double geoTransform[6];
globalOutputParameters( extent, width, height, geoTransform, pixelSize );
QgsRasterDataProvider* destProvider = initOutput( width, height, crs, geoTransform, 1, dataType, QList<bool>(), QList<double>() );
bool res = destProvider != nullptr;
delete destProvider;
return res;
}
QgsRasterFileWriter::QgsRasterFileWriter( const QString& outputUrl )
: mMode( Raw )
, mOutputUrl( outputUrl )

10
src/core/raster/qgsrasterfilewriter.h
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@ -55,6 +55,16 @@ class CORE_EXPORT QgsRasterFileWriter
QgsRasterFileWriter( const QString& outputUrl );
/** Create a raster file with one band without initializing the pixel data.
* @note Does not work with tiled mode enabled.
* @returns true when the raster has been created successfully
* @note added in QGIS 3.0
*/
bool createOneBandRaster( Qgis::DataType dataType,
int width, int height,
const QgsRectangle& extent,
const QgsCoordinateReferenceSystem& crs );
/** Write raster file
@param pipe raster pipe
@param nCols number of output columns

26
tests/src/core/testqgsrasterfilewriter.cpp
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@ -47,6 +47,7 @@ class TestQgsRasterFileWriter: public QObject
void cleanup() {} // will be called after every testfunction.
void writeTest();
void testCreateOneBandRaster();
private:
bool writeTest( const QString& rasterName );
void log( const QString& msg );
@ -178,6 +179,31 @@ bool TestQgsRasterFileWriter::writeTest( const QString& theRasterName )
return ok;
}
void TestQgsRasterFileWriter::testCreateOneBandRaster()
{
// generate unique filename (need to open the file first to generate it)
QTemporaryFile tmpFile;
tmpFile.open();
tmpFile.close();
QString filename = tmpFile.fileName();
QgsRectangle extent( 106.7, -6.2, 106.9, -6.1 );
int width = 200, height = 100;
QgsRasterFileWriter writer( filename );
bool res = writer.createOneBandRaster( Qgis::Byte, width, height, extent, QgsCoordinateReferenceSystem( "EPSG:4326" ) );
QVERIFY( res );
QgsRasterLayer* rlayer = new QgsRasterLayer( filename, "tmp", "gdal" );
QVERIFY( rlayer->isValid() );
QCOMPARE( rlayer->width(), width );
QCOMPARE( rlayer->height(), height );
QCOMPARE( rlayer->extent(), extent );
QCOMPARE( rlayer->bandCount(), 1 );
QCOMPARE( rlayer->dataProvider()->dataType( 1 ), Qgis::Byte );
}
void TestQgsRasterFileWriter::log( const QString& msg )
{
mReport += msg + "<br>";