From e5727224794620720f9b73098cce8c80b16ac304 Mon Sep 17 00:00:00 2001 From: Benjamin Gilbert Date: Mon, 23 Oct 2023 01:31:23 -0500 Subject: [PATCH] Allow configuring JPEG restart marker interval on save libjpeg allows specifying the marker interval either in MCU blocks or in MCU rows. Support both, via separate parameters, rather than requiring callers to do the math. Co-authored-by: Andrew Murray --- Tests/test_file_jpeg.py | 17 +++++++++++++++++ docs/handbook/image-file-formats.rst | 12 ++++++++++++ src/PIL/JpegImagePlugin.py | 2 ++ src/encode.c | 8 +++++++- src/libImaging/Jpeg.h | 4 ++++ src/libImaging/JpegEncode.c | 2 ++ 6 files changed, 44 insertions(+), 1 deletion(-) diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py index a0822d000..67cf761bb 100644 --- a/Tests/test_file_jpeg.py +++ b/Tests/test_file_jpeg.py @@ -643,6 +643,23 @@ class TestFileJpeg: assert max(im2.quantization[0]) <= 255 assert max(im2.quantization[1]) <= 255 + @pytest.mark.parametrize( + "blocks, rows, markers", + ((0, 0, 0), (1, 0, 15), (3, 0, 5), (8, 0, 1), (0, 1, 3), (0, 2, 1)), + ) + def test_restart_markers(self, blocks, rows, markers): + im = Image.new("RGB", (32, 32)) # 16 MCUs + out = BytesIO() + im.save( + out, + format="JPEG", + restart_marker_blocks=blocks, + restart_marker_rows=rows, + # force 8x8 pixel MCUs + subsampling=0, + ) + assert len(re.findall(b"\xff[\xd0-\xd7]", out.getvalue())) == markers + @pytest.mark.skipif(not djpeg_available(), reason="djpeg not available") def test_load_djpeg(self): with Image.open(TEST_FILE) as img: diff --git a/docs/handbook/image-file-formats.rst b/docs/handbook/image-file-formats.rst index 3cf5ad765..fe310df64 100644 --- a/docs/handbook/image-file-formats.rst +++ b/docs/handbook/image-file-formats.rst @@ -494,6 +494,18 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options: If absent, the setting will be determined by libjpeg or libjpeg-turbo. +**restart_marker_blocks** + If present, emit a restart marker whenever the specified number of MCU + blocks has been produced. + + .. versionadded:: 10.2.0 + +**restart_marker_rows** + If present, emit a restart marker whenever the specified number of MCU + rows has been produced. + + .. versionadded:: 10.2.0 + **qtables** If present, sets the qtables for the encoder. This is listed as an advanced option for wizards in the JPEG documentation. Use with diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py index c091697f5..3596e0899 100644 --- a/src/PIL/JpegImagePlugin.py +++ b/src/PIL/JpegImagePlugin.py @@ -787,6 +787,8 @@ def _save(im, fp, filename): dpi[0], dpi[1], subsampling, + info.get("restart_marker_blocks", 0), + info.get("restart_marker_rows", 0), qtables, comment, extra, diff --git a/src/encode.c b/src/encode.c index 08544aede..4664ad0f3 100644 --- a/src/encode.c +++ b/src/encode.c @@ -1045,6 +1045,8 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { Py_ssize_t streamtype = 0; /* 0=interchange, 1=tables only, 2=image only */ Py_ssize_t xdpi = 0, ydpi = 0; Py_ssize_t subsampling = -1; /* -1=default, 0=none, 1=medium, 2=high */ + Py_ssize_t restart_marker_blocks = 0; + Py_ssize_t restart_marker_rows = 0; PyObject *qtables = NULL; unsigned int *qarrays = NULL; int qtablesLen = 0; @@ -1057,7 +1059,7 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { if (!PyArg_ParseTuple( args, - "ss|nnnnnnnnOz#y#y#", + "ss|nnnnnnnnnnOz#y#y#", &mode, &rawmode, &quality, @@ -1068,6 +1070,8 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { &xdpi, &ydpi, &subsampling, + &restart_marker_blocks, + &restart_marker_rows, &qtables, &comment, &comment_size, @@ -1156,6 +1160,8 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { ((JPEGENCODERSTATE *)encoder->state.context)->streamtype = streamtype; ((JPEGENCODERSTATE *)encoder->state.context)->xdpi = xdpi; ((JPEGENCODERSTATE *)encoder->state.context)->ydpi = ydpi; + ((JPEGENCODERSTATE *)encoder->state.context)->restart_marker_blocks = restart_marker_blocks; + ((JPEGENCODERSTATE *)encoder->state.context)->restart_marker_rows = restart_marker_rows; ((JPEGENCODERSTATE *)encoder->state.context)->comment = comment; ((JPEGENCODERSTATE *)encoder->state.context)->comment_size = comment_size; ((JPEGENCODERSTATE *)encoder->state.context)->extra = extra; diff --git a/src/libImaging/Jpeg.h b/src/libImaging/Jpeg.h index 1d7550818..5cc74e69b 100644 --- a/src/libImaging/Jpeg.h +++ b/src/libImaging/Jpeg.h @@ -83,6 +83,10 @@ typedef struct { /* Chroma Subsampling (-1=default, 0=none, 1=medium, 2=high) */ int subsampling; + /* Restart marker interval, in MCU blocks or MCU rows, or 0 for none */ + unsigned int restart_marker_blocks; + unsigned int restart_marker_rows; + /* Converter input mode (input to the shuffler) */ char rawmode[8 + 1]; diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c index 2a24eff39..6a4b50bec 100644 --- a/src/libImaging/JpegEncode.c +++ b/src/libImaging/JpegEncode.c @@ -210,6 +210,8 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) { } context->cinfo.smoothing_factor = context->smooth; context->cinfo.optimize_coding = (boolean)context->optimize; + context->cinfo.restart_interval = context->restart_marker_blocks; + context->cinfo.restart_in_rows = context->restart_marker_rows; if (context->xdpi > 0 && context->ydpi > 0) { context->cinfo.write_JFIF_header = TRUE; context->cinfo.density_unit = 1; /* dots per inch */