From 464627feb864b6a593d28ea2f983a6e1c32738d9 Mon Sep 17 00:00:00 2001
From: Aarni Koskela <akx@iki.fi>
Date: Thu, 20 Aug 2026 09:32:45 +0300
Subject: [PATCH 1/2] Add benchmark for get_flattened_data

---
 Tests/benchmarks.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Tests/benchmarks.py b/Tests/benchmarks.py
index 11ed3cf743b..7bada08ba0c 100644
--- a/Tests/benchmarks.py
+++ b/Tests/benchmarks.py
@@ -898,3 +898,15 @@ def test_quantize_to_palette(
         result = bench(lambda: im._new(im.im.convert(output_mode, dither, palette.im)))
     assert result.mode == output_mode
     benchmark_save(result)
+
+
+@pytest.mark.benchmark
+@pytest.mark.parametrize("mode", MODES)
+@pytest.mark.parametrize("size", SIZES, ids=_format_size)
+def test_get_flattened_data(
+    bench: BenchmarkFixture,
+    mode: str,
+    size: tuple[int, int],
+) -> None:
+    im = make_pillow_image(mode, size)
+    bench(im.get_flattened_data)

From eb40a75d0a974c9ae125fe963b87dee79f8e5e9d Mon Sep 17 00:00:00 2001
From: Aarni Koskela <akx@iki.fi>
Date: Thu, 20 Aug 2026 11:08:28 +0300
Subject: [PATCH 2/2] Speed up getpixel() (and get_flattened_data() as a side
 effect)

* Build N-tuples by hand instead of Py_BuildValue parsing format strings over and over
* Tell the Python GC that the returned tuple contains no objects that may cause cycles
---
 src/_imaging.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/_imaging.c b/src/_imaging.c
index 9bdb6328782..bbaf83f307f 100644
--- a/src/_imaging.c
+++ b/src/_imaging.c
@@ -523,6 +523,27 @@ float16tofloat32(const FLOAT16 in) {
     return out[0];
 }
 
+static inline PyObject *
+make_pixel_tuple(const UINT8 *b, Py_ssize_t bands) {
+    PyObject *tuple = PyTuple_New(bands);
+    if (tuple == NULL) {
+        return NULL;
+    }
+    for (Py_ssize_t i = 0; i < bands; i++) {
+        PyObject *v = PyLong_FromLong(b[i]);
+        if (v == NULL) {
+            Py_DECREF(tuple);
+            return NULL;
+        }
+        PyTuple_SET_ITEM(tuple, i, v);
+    }
+    // We know these tuples will only have small integers,
+    // so we can tell the garbage collector to not look inside
+    // for cycles.
+    PyObject_GC_UnTrack(tuple);
+    return tuple;
+}
+
 static inline PyObject *
 getpixel(Imaging im, ImagingAccess access, int x, int y) {
     union {
@@ -552,13 +573,11 @@ getpixel(Imaging im, ImagingAccess access, int x, int y) {
                 case 1:
                     return PyLong_FromLong(pixel.b[0]);
                 case 2:
-                    return Py_BuildValue("BB", pixel.b[0], pixel.b[1]);
+                    return make_pixel_tuple(pixel.b, 2);
                 case 3:
-                    return Py_BuildValue("BBB", pixel.b[0], pixel.b[1], pixel.b[2]);
+                    return make_pixel_tuple(pixel.b, 3);
                 case 4:
-                    return Py_BuildValue(
-                        "BBBB", pixel.b[0], pixel.b[1], pixel.b[2], pixel.b[3]
-                    );
+                    return make_pixel_tuple(pixel.b, 4);
             }
             break;
         case IMAGING_TYPE_INT32: