From c4e271c2dc09c287a1940b3e57b93742bc9abf03 Mon Sep 17 00:00:00 2001
From: Arne Baeyens <mail@arnebaeyens.com>
Date: Sat, 22 Aug 2026 19:12:05 +0200
Subject: [PATCH] imgwarp add perf tests where src img much smaller then dst
 img + transparent border

As the existing perf tests don't cover this use case well. Did not do the CONSTANT border type because for that use case the source image is usually projected over about the whole of the destination image so our ROI optimization wouldn't deliver much user value there.

Signed-off-by: Arne Baeyens <mail@arnebaeyens.com>
---
 modules/imgproc/perf/perf_warp.cpp | 59 ++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/modules/imgproc/perf/perf_warp.cpp b/modules/imgproc/perf/perf_warp.cpp
index cb4c32c905..91c24e4699 100644
--- a/modules/imgproc/perf/perf_warp.cpp
+++ b/modules/imgproc/perf/perf_warp.cpp
@@ -16,6 +16,8 @@ typedef TestBaseWithParam< tuple<MatType, Size, InterType, BorderMode> > TestWar
 typedef TestBaseWithParam< tuple<Size, InterType, BorderMode, int> > TestWarpPerspective;
 typedef TestBaseWithParam< tuple<Size, InterType, BorderMode, MatType> > TestWarpPerspectiveNear_t;
 typedef TestBaseWithParam< tuple<MatType, Size, InterTypeExtended, BorderMode, RemapMode> > TestRemap;
+typedef TestBaseWithParam< tuple<MatType, Size, InterType> > TestWarpAffineSmallSrc;
+typedef TestBaseWithParam< tuple<MatType, Size, InterType> > TestWarpPerspectiveSmallSrc;
 
 void update_map(const Mat& src, Mat& map_x, Mat& map_y, const int remapMode, bool relative = false );
 
@@ -307,4 +309,61 @@ PERF_TEST(Transform, getPerspectiveTransform_QR_1000)
     SANITY_CHECK_NOTHING();
 }
 
+PERF_TEST_P( TestWarpAffineSmallSrc, WarpAffine_SmallSrc,
+             Combine(
+                Values(CV_8UC1, CV_8UC4),
+                Values( Size(512, 512) ),
+                InterType::all()
+             )
+)
+{
+    const Size   szSrc(64, 64);
+    const int    dataType   = get<0>(GetParam());
+    const Size   sz         = get<1>(GetParam());
+    const int    interType  = get<2>(GetParam());
+    const int    borderMode = BORDER_TRANSPARENT;
+
+    Mat src(szSrc, dataType), dst(sz, dataType, Scalar::all(0));
+    cvtest::fillGradient(src);
+
+    const double offset = (sz.width - szSrc.width) / 2.0;
+    const Mat warpMat = (Mat_<double>(2, 3) << 1, 0, offset,
+                                               0, 1, offset);
+    declare.in(src).out(dst);
+
+    TEST_CYCLE() warpAffine( src, dst, warpMat, sz, interType, borderMode );
+
+    SANITY_CHECK_NOTHING();
+}
+
+PERF_TEST_P( TestWarpPerspectiveSmallSrc, WarpPerspective_SmallSrc,
+             Combine(
+                Values(CV_8UC1, CV_8UC4),
+                Values( Size(512, 512) ),
+                InterType::all()
+             )
+)
+{
+    const Size   szSrc(64, 64);
+    const int    dataType   = get<0>(GetParam());
+    const Size   sz         = get<1>(GetParam());
+    const int    interType  = get<2>(GetParam());
+    const int    borderMode = BORDER_TRANSPARENT;
+
+    Mat src(szSrc, dataType), dst(sz, dataType, Scalar::all(0));
+    cvtest::fillGradient(src);
+
+    const float w = (float)szSrc.width, h = (float)szSrc.height;
+    const float off = (sz.width - szSrc.width) / 2.0f;
+    const Point2f sp[] = { Point2f(0, 0), Point2f(w, 0), Point2f(0, h), Point2f(w, h) };
+    const Point2f dp[] = { Point2f(off,     off),     Point2f(off + w, off),
+                           Point2f(off,     off + h), Point2f(off + w, off + h) };
+    const Mat warpMat = getPerspectiveTransform(sp, dp);
+    declare.in(src).out(dst);
+
+    TEST_CYCLE() warpPerspective( src, dst, warpMat, sz, interType, borderMode );
+
+    SANITY_CHECK_NOTHING();
+}
+
 } // namespace