JP2OpenJPEG: fix reading overviews, when tiled API is used, and the d…

…imensions of the full resolution image are not a multiple of 2^numresolutions (fixes #1860)
OSGeo · Sep 19, 2019 · 44fcc1b · 44fcc1b
1 parent dd7abfb
commit 44fcc1b
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Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/autotest/gdrivers/jp2openjpeg.py b/autotest/gdrivers/jp2openjpeg.py
@@ -3094,6 +3094,22 @@ def test_jp2openjpeg_external_overviews_multiple_band():
     assert cs == [6233, 7706, 26085]
 
 ###############################################################################
+# Test accessing overview levels when the dimensions of the full resolution
+# image are not a multiple of 2^numresolutions
+
+
+def test_jp2openjpeg_odd_dimensions():
+
+    if gdaltest.jp2openjpeg_drv is None:
+        pytest.skip()
+
+    ds = gdal.Open('data/513x513.jp2')
+    cs = ds.GetRasterBand(1).GetOverview(0).Checksum()
+    ds = None
+
+    assert cs == 29642
+
+###############################################################################
 
 
 def test_jp2openjpeg_cleanup():

diff --git a/gdal/frmts/openjpeg/openjpegdataset.cpp b/gdal/frmts/openjpeg/openjpegdataset.cpp
@@ -2162,8 +2162,9 @@ GDALDataset *JP2OpenJPEGDataset::Open( GDALOpenInfo * poOpenInfo )
            (nW > 128 || nH > 128) &&
            (poDS->bUseSetDecodeArea || ((nTileW % 2) == 0 && (nTileH % 2) == 0)))
     {
-        nW /= 2;
-        nH /= 2;
+        // This must be this exact formula per the JPEG2000 standard
+        nW = (nW + 1) / 2;
+        nH = (nH + 1) / 2;
 
         poDS->papoOverviewDS = (JP2OpenJPEGDataset**) CPLRealloc(
                     poDS->papoOverviewDS,