[gdalwarp] Fix -ovr {absolute_value} (#10193)

Fix #10174 -ovr {absolute_value} doesn't influence choice of output resolution
OSGeo · Jun 12, 2024 · 75c9020 · 75c9020
1 parent 6bd9d23
commit 75c9020
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Showing 2 changed files with 39 additions and 0 deletions.
diff --git a/apps/gdalwarp_lib.cpp b/apps/gdalwarp_lib.cpp
@@ -3680,6 +3680,18 @@ static GDALDatasetH GDALWarpCreateOutput(
             return nullptr;
         }
 
+        // Examine desired overview level and retrieve the corresponding dataset
+        // if it exists.
+        std::unique_ptr<GDALDataset> oDstDSOverview;
+        if (psOptions->nOvLevel >= 0)
+        {
+            oDstDSOverview.reset(GDALCreateOverviewDataset(
+                GDALDataset::FromHandle(hSrcDS), psOptions->nOvLevel,
+                /* bThisLevelOnly = */ true));
+            if (oDstDSOverview)
+                hSrcDS = oDstDSOverview.get();
+        }
+
         /* --------------------------------------------------------------------
          */
         /*      Check if the source dataset shares some files with the dest
@@ -4110,6 +4122,7 @@ static GDALDatasetH GDALWarpCreateOutput(
             {
                 nOptions |= GDAL_SWO_FORCE_SQUARE_PIXEL;
             }
+
             if (GDALSuggestedWarpOutput2(hSrcDS, psInfo->pfnTransform,
                                          hTransformArg, adfThisGeoTransform,
                                          &nThisPixels, &nThisLines, adfExtent,

diff --git a/autotest/utilities/test_gdalwarp.py b/autotest/utilities/test_gdalwarp.py
@@ -30,6 +30,7 @@
 ###############################################################################
 
 import os
+import shutil
 import stat
 
 import gdaltest
@@ -1049,6 +1050,7 @@ def test_gdalwarp_39(gdalwarp_path, tmp_path):
 def test_gdalwarp_40(gdalwarp_path, tmp_path):
 
     src_tif = str(tmp_path / "test_gdalwarp_40_src.tif")
+    src_tif_copy = str(tmp_path / "test_gdalwarp_40_src_copy.tif")
     dst_tif = str(tmp_path / "test_gdalwarp_40.tif")
     dst_vrt = str(tmp_path / "test_gdalwarp_40.vrt")
 
@@ -1060,8 +1062,11 @@ def test_gdalwarp_40(gdalwarp_path, tmp_path):
     cs_ov0 = out_ds.GetRasterBand(1).GetOverview(0).Checksum()
     out_ds.GetRasterBand(1).GetOverview(1).Fill(255)
     cs_ov1 = out_ds.GetRasterBand(1).GetOverview(1).Checksum()
+
     out_ds = None
 
+    shutil.copy(src_tif, src_tif_copy)
+
     # Should select main resolution
     gdaltest.runexternal(f"{gdalwarp_path} {src_tif} {dst_tif} -overwrite")
 
@@ -1113,6 +1118,27 @@ def test_gdalwarp_40(gdalwarp_path, tmp_path):
     assert ds.GetRasterBand(1).Checksum() == cs_ov0
     ds = None
 
+    # Should select overview 0
+    gdaltest.runexternal(f"{gdalwarp_path} {src_tif} {dst_tif} -overwrite -ovr 0")
+
+    ds = gdal.Open(dst_tif)
+    assert ds.GetRasterBand(1).Checksum() == cs_ov0
+    ds = None
+
+    # Should select overview 0 (no overwrite)
+    gdaltest.runexternal(f"{gdalwarp_path} {src_tif} {dst_tif} -ovr 0")
+
+    # Repeat with no output file and no overwrite (takes a different code path)
+    os.unlink(dst_tif)
+    gdaltest.runexternal(f"{gdalwarp_path} {src_tif} {dst_tif} -ovr 0")
+
+    # Should not crash (actually it never did)
+    os.unlink(dst_tif)
+    gdaltest.runexternal(f"{gdalwarp_path} {src_tif} {src_tif_copy} {dst_tif} -ovr 0")
+    ds = gdal.Open(dst_tif)
+    assert ds.GetRasterBand(1).Checksum() == cs_ov0
+    ds = None
+
     # Should select overview 0 through VRT
     gdaltest.runexternal(
         f"{gdalwarp_path} {src_tif} {dst_vrt} -overwrite -ts 10 10 -of VRT"