1 files changed, 66 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/preview_test.cc b/third_party/jpeg-xl/lib/jxl/preview_test.cc
new file mode 100644
index 0000000000..b7fe855d4d
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/preview_test.cc
@@ -0,0 +1,66 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <jxl/cms.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "lib/extras/codec.h"
+#include "lib/jxl/base/span.h"
+#include "lib/jxl/codec_in_out.h"
+#include "lib/jxl/enc_butteraugli_comparator.h"
+#include "lib/jxl/enc_params.h"
+#include "lib/jxl/headers.h"
+#include "lib/jxl/image_bundle.h"
+#include "lib/jxl/test_utils.h"
+#include "lib/jxl/testing.h"
+
+namespace jxl {
+namespace {
+using test::ReadTestData;
+using test::Roundtrip;
+
+TEST(PreviewTest, RoundtripGivenPreview) {
+  const std::vector<uint8_t> orig =
+      ReadTestData("external/wesaturate/500px/u76c0g_bliznaca_srgb8.png");
+  CodecInOut io;
+  ASSERT_TRUE(SetFromBytes(Bytes(orig), &io));
+  io.ShrinkTo(io.xsize() / 8, io.ysize() / 8);
+  // Same as main image
+  io.preview_frame = io.Main().Copy();
+  const size_t preview_xsize = 15;
+  const size_t preview_ysize = 27;
+  io.preview_frame.ShrinkTo(preview_xsize, preview_ysize);
+  io.metadata.m.have_preview = true;
+  ASSERT_TRUE(io.metadata.m.preview_size.Set(io.preview_frame.xsize(),
+                                             io.preview_frame.ysize()));
+
+  CompressParams cparams;
+  cparams.butteraugli_distance = 2.0;
+  cparams.speed_tier = SpeedTier::kSquirrel;
+  cparams.SetCms(*JxlGetDefaultCms());
+
+  CodecInOut io2;
+  JXL_EXPECT_OK(Roundtrip(&io, cparams, {}, &io2, _));
+  EXPECT_EQ(preview_xsize, io2.metadata.m.preview_size.xsize());
+  EXPECT_EQ(preview_ysize, io2.metadata.m.preview_size.ysize());
+  EXPECT_EQ(preview_xsize, io2.preview_frame.xsize());
+  EXPECT_EQ(preview_ysize, io2.preview_frame.ysize());
+
+  EXPECT_LE(ButteraugliDistance(io.preview_frame, io2.preview_frame,
+                                ButteraugliParams(), *JxlGetDefaultCms(),
+                                /*distmap=*/nullptr),
+            2.5);
+  EXPECT_LE(ButteraugliDistance(io.Main(), io2.Main(), ButteraugliParams(),
+                                *JxlGetDefaultCms(),
+                                /*distmap=*/nullptr),
+            2.5);
+}
+
+}  // namespace
+}  // namespace jxl