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GDALOpenEx(): supports OVERVIEW_LEVEL=NONE to indicate overviews shou…
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…ldn't be exposed

Adresses https://rasterio.groups.io/g/main/message/649
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@rouault
rouault committed Nov 13, 2020
1 parent cb2f706 commit d7963d8
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Showing 3 changed files with 58 additions and 29 deletions.
30 changes: 22 additions & 8 deletions autotest/gcore/overviewds.py
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Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,6 @@


def test_overviewds_1():
ds = gdal.OpenEx('data/byte.tif', open_options=['OVERVIEW_LEVEL=-1'])
assert ds is None
ds = gdal.OpenEx('data/byte.tif', open_options=['OVERVIEW_LEVEL=0'])
assert ds is None

Expand All @@ -56,13 +54,27 @@ def test_overviewds_2():
shutil.copy('data/byte.tif', 'tmp')
ds = gdal.Open('tmp/byte.tif')
ds.BuildOverviews('NEAR', overviewlist=[2, 4])
ds.GetRasterBand(1).WriteRaster(2, 2, 5, 5, b'\0' * 25)
ds.GetRasterBand(1).WriteRaster(2, 2, 1, 1, b'\0')
ds = None

src_ds = gdal.Open('tmp/byte.tif')

ds = gdal.OpenEx('data/byte.tif', open_options=['OVERVIEW_LEVEL=NONE'])
assert ds.RasterXSize == 20 and ds.RasterYSize == 20 and ds.RasterCount == 1
assert ds.GetRasterBand(1).GetOverviewCount() == 0
assert ds.GetProjectionRef() == src_ds.GetProjectionRef()
assert ds.GetGeoTransform() == src_ds.GetGeoTransform()
assert ds.ReadRaster() == src_ds.ReadRaster()
# Check that subsampled request doesn't use source overviews
assert ds.ReadRaster(0, 0, 20, 20, 10, 10) != src_ds.GetRasterBand(1).GetOverview(0).ReadRaster()
ds = None

ds = gdal.OpenEx('tmp/byte.tif', open_options=['OVERVIEW_LEVEL=0only'])
assert ds.RasterXSize == 10 and ds.RasterYSize == 10 and ds.RasterCount == 1
assert ds.GetRasterBand(1).GetOverviewCount() == 0
ds = None

src_ds = gdal.Open('tmp/byte.tif')
ds = gdal.OpenEx('tmp/byte.tif', open_options=['OVERVIEW_LEVEL=0'])
assert ds is not None
assert ds.RasterXSize == 10 and ds.RasterYSize == 10 and ds.RasterCount == 1
Expand All @@ -73,14 +85,16 @@ def test_overviewds_2():
for i in range(6):
assert expected_gt[i] == pytest.approx(gt[i], abs=1e-5)
assert ds.GetGCPCount() == 0 and ds.GetGCPProjection() == src_ds.GetGCPProjection() and not ds.GetGCPs()
expected_data = src_ds.ReadRaster(0, 0, 20, 20, 10, 10)
got_data = ds.ReadRaster(0, 0, 10, 10)
expected_data = src_ds.GetRasterBand(1).GetOverview(0).ReadRaster()
got_data = ds.ReadRaster()
assert expected_data == got_data
got_data = ds.GetRasterBand(1).ReadRaster(0, 0, 10, 10)
got_data = ds.GetRasterBand(1).ReadRaster()
assert expected_data == got_data
assert ds.GetRasterBand(1).GetOverviewCount() == 1
expected_data = src_ds.ReadRaster(0, 0, 20, 20, 5, 5)
got_data = ds.GetRasterBand(1).GetOverview(0).ReadRaster(0, 0, 5, 5)
expected_data = src_ds.GetRasterBand(1).GetOverview(1).ReadRaster()
got_data = ds.GetRasterBand(1).GetOverview(0).ReadRaster()
assert expected_data == got_data
got_data = ds.ReadRaster(0, 0, 10, 10, 5, 5)
assert expected_data == got_data
assert ds.GetRasterBand(1).GetMaskFlags() == gdal.GMF_ALL_VALID
assert ds.GetRasterBand(1).GetMaskBand()
Expand Down
6 changes: 4 additions & 2 deletions gdal/gcore/gdaldataset.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3223,6 +3223,8 @@ GDALOpen( const char * pszFilename, GDALAccess eAccess )
* VALIDATE_OPEN_OPTIONS can be set to NO to avoid such warnings. Alternatively,
* since GDAL 2.1, an option name can be preceded by the @ character to indicate
* that it may not cause a warning if the driver doesn't declare this option.
* Starting with GDAL 3.3, OVERVIEW_LEVEL=NONE is supported to indicate that
* no overviews should be exposed.
*
* @param papszSiblingFiles NULL, or a NULL terminated list of strings that are
* filenames that are auxiliary to the main filename. If NULL is passed, a
Expand Down Expand Up @@ -3486,9 +3488,9 @@ GDALDatasetH CPL_STDCALL GDALOpenEx( const char *pszFilename,
{
CPLString osVal(
CSLFetchNameValue(papszOpenOptions, "OVERVIEW_LEVEL"));
const int nOvrLevel = atoi(osVal);
const int nOvrLevel = EQUAL(osVal, "NONE") ? -1 : atoi(osVal);
const bool bThisLevelOnly =
osVal.ifind("only") != std::string::npos;
nOvrLevel == -1 || osVal.ifind("only") != std::string::npos;
GDALDataset *poOvrDS = GDALCreateOverviewDataset(
poDS, nOvrLevel, bThisLevelOnly);
poDS->ReleaseRef();
Expand Down
51 changes: 32 additions & 19 deletions gdal/gcore/gdaloverviewdataset.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -133,11 +133,24 @@ class GDALOverviewBand final: public GDALProxyRasterBand
CPL_DISALLOW_COPY_ASSIGN(GDALOverviewBand)
};

/************************************************************************/
/* GetOverviewEx() */
/************************************************************************/

static GDALRasterBand* GetOverviewEx(GDALRasterBand* poBand, int nLevel)
{
if( nLevel == -1 )
return poBand;
return poBand->GetOverview(nLevel);
}

/************************************************************************/
/* GDALCreateOverviewDataset() */
/************************************************************************/

// Takes a reference on poMainDS in case of success.
// nOvrLevel=-1 means the full resolution dataset (only useful if
// bThisLevelOnly = false to expose a dataset without its overviews)
GDALDataset* GDALCreateOverviewDataset( GDALDataset* poMainDS, int nOvrLevel,
int bThisLevelOnly )
{
Expand All @@ -146,16 +159,16 @@ GDALDataset* GDALCreateOverviewDataset( GDALDataset* poMainDS, int nOvrLevel,
if( nBands == 0 )
return nullptr;

auto poFirstBand = GetOverviewEx(poMainDS->GetRasterBand(1), nOvrLevel);
for( int i = 1; i<= nBands; ++i )
{
if( poMainDS->GetRasterBand(i)->GetOverview(nOvrLevel) == nullptr )
auto poBand = GetOverviewEx(poMainDS->GetRasterBand(i), nOvrLevel);
if( poBand == nullptr )
{
return nullptr;
}
if( poMainDS->GetRasterBand(i)->GetOverview(nOvrLevel)->GetXSize() !=
poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetXSize() ||
poMainDS->GetRasterBand(i)->GetOverview(nOvrLevel)->GetYSize() !=
poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetYSize() )
if( poBand->GetXSize() != poFirstBand->GetXSize() ||
poBand->GetYSize() != poFirstBand->GetYSize() )
{
return nullptr;
}
Expand All @@ -177,12 +190,11 @@ GDALOverviewDataset::GDALOverviewDataset( GDALDataset* poMainDSIn,
{
poMainDSIn->Reference();
eAccess = poMainDS->GetAccess();
nRasterXSize =
poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetXSize();
nRasterYSize =
poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetYSize();
poOvrDS = poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetDataset();
if( poOvrDS != nullptr && poOvrDS == poMainDS )
auto poFirstBand = GetOverviewEx(poMainDS->GetRasterBand(1), nOvrLevel);
nRasterXSize = poFirstBand->GetXSize();
nRasterYSize = poFirstBand->GetYSize();
poOvrDS = poFirstBand->GetDataset();
if( nOvrLevel != -1 && poOvrDS != nullptr && poOvrDS == poMainDS )
{
CPLDebug( "GDAL",
"Dataset of overview is the same as the main band. "
Expand All @@ -195,9 +207,9 @@ GDALOverviewDataset::GDALOverviewDataset( GDALDataset* poMainDSIn,
SetBand(i+1, new GDALOverviewBand(this, i+1));
}

if( poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetMaskFlags() == GMF_PER_DATASET )
if( poFirstBand->GetMaskFlags() == GMF_PER_DATASET )
{
auto poOvrMaskBand = poMainDS->GetRasterBand(1)->GetOverview(nOvrLevel)->GetMaskBand();
auto poOvrMaskBand = poFirstBand->GetMaskBand();
if( poOvrMaskBand && poOvrMaskBand->GetXSize() == nRasterXSize &&
poOvrMaskBand->GetYSize() == nRasterYSize )
{
Expand All @@ -224,7 +236,8 @@ GDALOverviewDataset::GDALOverviewDataset( GDALDataset* poMainDSIn,
papszOpenOptions = CSLDuplicate(poMainDS->GetOpenOptions());
// Add OVERVIEW_LEVEL if not called from GDALOpenEx(), but directly.
papszOpenOptions = CSLSetNameValue(papszOpenOptions, "OVERVIEW_LEVEL",
CPLSPrintf("%d", nOvrLevel));
nOvrLevel == -1 ? "NONE" :
CPLSPrintf("%d%s", nOvrLevel, bThisLevelOnly ? " only" :""));
}

/************************************************************************/
Expand Down Expand Up @@ -309,7 +322,7 @@ CPLErr GDALOverviewDataset::IRasterIO( GDALRWFlag eRWFlag,
{
// In case the overview bands are really linked to a dataset, then issue
// the request to that dataset.
if( poOvrDS != nullptr )
if( nOvrLevel != -1 && poOvrDS != nullptr )
{
return poOvrDS->RasterIO(
eRWFlag, nXOff, nYOff, nXSize, nYSize, pData, nBufXSize, nBufYSize,
Expand Down Expand Up @@ -558,13 +571,13 @@ GDALOverviewBand::GDALOverviewBand( GDALOverviewDataset* poDSIn, int nBandIn )
nRasterYSize = poDSIn->nRasterYSize;
if( nBandIn == 0 )
{
poUnderlyingBand = poDSIn->poMainDS->GetRasterBand(1)->
GetOverview(poDSIn->nOvrLevel)->GetMaskBand();
poUnderlyingBand =
GetOverviewEx(poDSIn->poMainDS->GetRasterBand(1), poDSIn->nOvrLevel)->GetMaskBand();
}
else
{
poUnderlyingBand = poDSIn->poMainDS->GetRasterBand(nBandIn)->
GetOverview(poDSIn->nOvrLevel);
poUnderlyingBand =
GetOverviewEx(poDSIn->poMainDS->GetRasterBand(nBandIn), poDSIn->nOvrLevel);
}
eDataType = poUnderlyingBand->GetRasterDataType();
poUnderlyingBand->GetBlockSize(&nBlockXSize, &nBlockYSize);
Expand Down

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