Do not use MozJPEG progressive default

radarhere · Dec 31, 2024 · 19d4fdb · 19d4fdb
1 parent c3fac1d
commit 19d4fdb
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
@@ -281,7 +281,10 @@ def test_progressive(self) -> None:
         assert not im2.info.get("progressive")
         assert im3.info.get("progressive")
 
-        assert_image_equal(im1, im3)
+        if features.check_feature("mozjpeg"):
+            assert_image_similar(im1, im3, 9.39)
+        else:
+            assert_image_equal(im1, im3)
         assert im1_bytes >= im3_bytes
 
     def test_progressive_large_buffer(self, tmp_path: Path) -> None:

diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c
@@ -134,7 +134,16 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
                     return -1;
             }
 
-            /* Compressor configuration */
+                /* Compressor configuration */
+#ifdef JPEG_C_PARAM_SUPPORTED
+            /* MozJPEG */
+            if (!context->progressive) {
+                /* Do not use MozJPEG progressive default */
+                jpeg_c_set_int_param(
+                    &context->cinfo, JINT_COMPRESS_PROFILE, JCP_FASTEST
+                );
+            }
+#endif
             jpeg_set_defaults(&context->cinfo);
 
             /* Prevent RGB -> YCbCr conversion */