Merge pull request #4639 from radarhere/jfif

Write JFIF header when saving JPEG
python-pillow · Jun 20, 2020 · bcb8cbb · bcb8cbb
2 parents 2d9dcc7 + 696aa79
commit bcb8cbb
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
@@ -90,9 +90,12 @@ def test_cmyk(self):
             ]
             assert k > 0.9
 
-    def test_dpi(self):
+    @pytest.mark.parametrize(
+        "test_image_path", [TEST_FILE, "Tests/images/pil_sample_cmyk.jpg"],
+    )
+    def test_dpi(self, test_image_path):
         def test(xdpi, ydpi=None):
-            with Image.open(TEST_FILE) as im:
+            with Image.open(test_image_path) as im:
                 im = self.roundtrip(im, dpi=(xdpi, ydpi or xdpi))
             return im.info.get("dpi")
 

diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c
@@ -222,6 +222,7 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
                 context->cinfo.smoothing_factor = context->smooth;
                 context->cinfo.optimize_coding = (boolean) context->optimize;
                 if (context->xdpi > 0 && context->ydpi > 0) {
+                    context->cinfo.write_JFIF_header = TRUE;
                     context->cinfo.density_unit = 1; /* dots per inch */
                     context->cinfo.X_density = context->xdpi;
                     context->cinfo.Y_density = context->ydpi;