diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py index e60ceb18a6d..979c7e33d00 100644 --- a/Tests/test_file_jpeg.py +++ b/Tests/test_file_jpeg.py @@ -142,6 +142,19 @@ def test_cmyk(self): ) assert k > 0.9 + def test_rgb(self): + def getchannels(im): + return tuple(v[0] for v in im.layer) + + im = hopper() + im_ycbcr = self.roundtrip(im) + assert getchannels(im_ycbcr) == (1, 2, 3) + assert_image_similar(im, im_ycbcr, 17) + + im_rgb = self.roundtrip(im, keep_rgb=True) + assert getchannels(im_rgb) == (ord("R"), ord("G"), ord("B")) + assert_image_similar(im, im_rgb, 12) + @pytest.mark.parametrize( "test_image_path", [TEST_FILE, "Tests/images/pil_sample_cmyk.jpg"], @@ -423,25 +436,28 @@ def getsampling(im): return layer[0][1:3] + layer[1][1:3] + layer[2][1:3] # experimental API - im = self.roundtrip(hopper(), subsampling=-1) # default - assert getsampling(im) == (2, 2, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling=0) # 4:4:4 - assert getsampling(im) == (1, 1, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling=1) # 4:2:2 - assert getsampling(im) == (2, 1, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling=2) # 4:2:0 - assert getsampling(im) == (2, 2, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling=3) # default (undefined) - assert getsampling(im) == (2, 2, 1, 1, 1, 1) - - im = self.roundtrip(hopper(), subsampling="4:4:4") - assert getsampling(im) == (1, 1, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling="4:2:2") - assert getsampling(im) == (2, 1, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling="4:2:0") - assert getsampling(im) == (2, 2, 1, 1, 1, 1) - im = self.roundtrip(hopper(), subsampling="4:1:1") - assert getsampling(im) == (2, 2, 1, 1, 1, 1) + for subsampling in (-1, 3): # (default, invalid) + im = self.roundtrip(hopper(), subsampling=subsampling) + assert getsampling(im) == (2, 2, 1, 1, 1, 1) + for subsampling in (0, "4:4:4"): + im = self.roundtrip(hopper(), subsampling=subsampling) + assert getsampling(im) == (1, 1, 1, 1, 1, 1) + for subsampling in (1, "4:2:2"): + im = self.roundtrip(hopper(), subsampling=subsampling) + assert getsampling(im) == (2, 1, 1, 1, 1, 1) + for subsampling in (2, "4:2:0", "4:1:1"): + im = self.roundtrip(hopper(), subsampling=subsampling) + assert getsampling(im) == (2, 2, 1, 1, 1, 1) + + # RGB colorspace + for subsampling in (-1, 0, "4:4:4"): + # "4:4:4" doesn't really make sense for RGB, but the conversion + # to an integer happens at a higher level + im = self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling) + assert getsampling(im) == (1, 1, 1, 1, 1, 1) + for subsampling in (1, "4:2:2", 2, "4:2:0", 3): + with pytest.raises(OSError): + self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling) with pytest.raises(TypeError): self.roundtrip(hopper(), subsampling="1:1:1") diff --git a/docs/handbook/image-file-formats.rst b/docs/handbook/image-file-formats.rst index 53565dbbdb3..276838bed1b 100644 --- a/docs/handbook/image-file-formats.rst +++ b/docs/handbook/image-file-formats.rst @@ -487,6 +487,16 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options: **exif** If present, the image will be stored with the provided raw EXIF data. +**keep_rgb** + By default, libjpeg converts images with an RGB color space to YCbCr. + If this option is present and true, those images will be stored as RGB + instead. + + When this option is enabled, attempting to chroma-subsample RGB images + with the ``subsampling`` option will raise an :py:exc:`OSError`. + + .. versionadded:: 10.2.0 + **subsampling** If present, sets the subsampling for the encoder. diff --git a/docs/releasenotes/10.2.0.rst b/docs/releasenotes/10.2.0.rst index d1f549e9c51..c3947f64c2e 100644 --- a/docs/releasenotes/10.2.0.rst +++ b/docs/releasenotes/10.2.0.rst @@ -42,6 +42,14 @@ Added DdsImagePlugin enums :py:class:`~PIL.DdsImagePlugin.DXGI_FORMAT` and :py:class:`~PIL.DdsImagePlugin.D3DFMT` enums have been added to :py:class:`PIL.DdsImagePlugin`. +JPEG RGB color space +^^^^^^^^^^^^^^^^^^^^ + +When saving JPEG files, ``keep_rgb`` can now be set to ``True``. This will store RGB +images in the RGB color space instead of being converted to YCbCr automatically by +libjpeg. When this option is enabled, attempting to chroma-subsample RGB images with +the ``subsampling`` option will raise an :py:exc:`OSError`. + JPEG restart marker interval ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py index e6b8320402a..81b8749a332 100644 --- a/src/PIL/JpegImagePlugin.py +++ b/src/PIL/JpegImagePlugin.py @@ -785,6 +785,7 @@ def validate_qtables(qtables): progressive, info.get("smooth", 0), optimize, + info.get("keep_rgb", False), info.get("streamtype", 0), dpi[0], dpi[1], diff --git a/src/encode.c b/src/encode.c index 4664ad0f32a..c7dd510150e 100644 --- a/src/encode.c +++ b/src/encode.c @@ -1042,6 +1042,7 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { Py_ssize_t progressive = 0; Py_ssize_t smooth = 0; Py_ssize_t optimize = 0; + int keep_rgb = 0; 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 */ @@ -1059,13 +1060,14 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { if (!PyArg_ParseTuple( args, - "ss|nnnnnnnnnnOz#y#y#", + "ss|nnnnpnnnnnnOz#y#y#", &mode, &rawmode, &quality, &progressive, &smooth, &optimize, + &keep_rgb, &streamtype, &xdpi, &ydpi, @@ -1150,6 +1152,7 @@ PyImaging_JpegEncoderNew(PyObject *self, PyObject *args) { strncpy(((JPEGENCODERSTATE *)encoder->state.context)->rawmode, rawmode, 8); + ((JPEGENCODERSTATE *)encoder->state.context)->keep_rgb = keep_rgb; ((JPEGENCODERSTATE *)encoder->state.context)->quality = quality; ((JPEGENCODERSTATE *)encoder->state.context)->qtables = qarrays; ((JPEGENCODERSTATE *)encoder->state.context)->qtablesLen = qtablesLen; diff --git a/src/libImaging/Jpeg.h b/src/libImaging/Jpeg.h index 5cc74e69bf5..98eaac28dd6 100644 --- a/src/libImaging/Jpeg.h +++ b/src/libImaging/Jpeg.h @@ -74,6 +74,9 @@ typedef struct { /* Optimize Huffman tables (slow) */ int optimize; + /* Disable automatic conversion of RGB images to YCbCr if nonzero */ + int keep_rgb; + /* Stream type (0=full, 1=tables only, 2=image only) */ int streamtype; diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c index 9da830b186f..00f3d5f74db 100644 --- a/src/libImaging/JpegEncode.c +++ b/src/libImaging/JpegEncode.c @@ -137,6 +137,30 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) { /* Compressor configuration */ jpeg_set_defaults(&context->cinfo); + /* Prevent RGB -> YCbCr conversion */ + if (context->keep_rgb) { + switch (context->cinfo.in_color_space) { + case JCS_RGB: +#ifdef JCS_EXTENSIONS + case JCS_EXT_RGBX: +#endif + switch (context->subsampling) { + case -1: /* Default */ + case 0: /* No subsampling */ + break; + default: + /* Would subsample the green and blue + channels, which doesn't make sense */ + state->errcode = IMAGING_CODEC_CONFIG; + return -1; + } + jpeg_set_colorspace(&context->cinfo, JCS_RGB); + break; + default: + break; + } + } + /* Use custom quantization tables */ if (context->qtables) { int i;