From 9e6157d74f624a464969d558ed633afa0de8f540 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. --- Tests/test_file_jpeg.py | 25 +++++++++++++++++++++++++ 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, 52 insertions(+), 1 deletion(-) diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py index a0822d0002c..c02e53b8cc5 100644 --- a/Tests/test_file_jpeg.py +++ b/Tests/test_file_jpeg.py @@ -643,6 +643,31 @@ def test_save_low_quality_baseline_qtables(self): assert max(im2.quantization[0]) <= 255 assert max(im2.quantization[1]) <= 255 + def test_restart_markers(self): + im = Image.new("RGB", (32, 32)) # 16 MCUs + cases = ( + (0, 0, 0), + (1, 0, 15), + (3, 0, 5), + (8, 0, 1), + (0, 1, 3), + (0, 2, 1), + ) + for blocks, rows, markers in cases: + out = BytesIO() + im.save( + out, + format="JPEG", + restart_marker_blocks=blocks, + restart_marker_rows=rows, + # force 8x8 pixel MCUs + subsampling=0, + ) + found_markers = sum( + len(out.getvalue().split(bytes([0xFF, 0xD0 + i]))) - 1 for i in range(8) + ) + assert markers == found_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 d5d95d3ce1a..32a184215b8 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 c091697f52d..3596e089949 100644 --- a/src/PIL/JpegImagePlugin.py +++ b/src/PIL/JpegImagePlugin.py @@ -787,6 +787,8 @@ def validate_qtables(qtables): 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 08544aedeb0..4664ad0f32a 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 1d755081871..5cc74e69bf5 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 2a24eff39ca..6a4b50becec 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 */