diff --git a/Tests/test_file_webp.py b/Tests/test_file_webp.py index 6ccd489bb..247fc6021 100644 --- a/Tests/test_file_webp.py +++ b/Tests/test_file_webp.py @@ -157,6 +157,17 @@ class TestFileWebp: im.save(temp_file, method=0) assert str(e.value) == "encoding error 6" + @pytest.mark.skipif(sys.maxsize <= 2**32, reason="Requires 64-bit system") + def test_write_encoding_error_bad_dimension(self, tmp_path: Path) -> None: + temp_file = str(tmp_path / "temp.webp") + im = Image.new("L", (16384, 16384)) + with pytest.raises(ValueError) as e: + im.save(temp_file) + assert ( + str(e.value) + == "encoding error 5: Image size exceeds WebP limit of 16383 pixels" + ) + def test_WebPEncode_with_invalid_args(self) -> None: """ Calling encoder functions with no arguments should result in an error. diff --git a/src/_webp.c b/src/_webp.c index d1943b3e0..f59ad3036 100644 --- a/src/_webp.c +++ b/src/_webp.c @@ -672,7 +672,16 @@ WebPEncode_wrapper(PyObject *self, PyObject *args) { WebPPictureFree(&pic); if (!ok) { - PyErr_Format(PyExc_ValueError, "encoding error %d", (&pic)->error_code); + int error_code = (&pic)->error_code; + char message[50] = ""; + if (error_code == VP8_ENC_ERROR_BAD_DIMENSION) { + sprintf( + message, + ": Image size exceeds WebP limit of %d pixels", + WEBP_MAX_DIMENSION + ); + } + PyErr_Format(PyExc_ValueError, "encoding error %d%s", error_code, message); return NULL; } output = writer.mem;