Merge pull request #8807 from radarhere/dxt1

Support saving DDS images with pixel formats

Author: hugovk

Tests/test_file_dds.py

@@ -9,7 +9,13 @@
 
 from PIL import DdsImagePlugin, Image
 
-from .helper import assert_image_equal, assert_image_equal_tofile, hopper
+from .helper import (
+    assert_image_equal,
+    assert_image_equal_tofile,
+    assert_image_similar,
+    assert_image_similar_tofile,
+    hopper,
+)
 
 TEST_FILE_DXT1 = "Tests/images/dxt1-rgb-4bbp-noalpha_MipMaps-1.dds"
 TEST_FILE_DXT3 = "Tests/images/dxt3-argb-8bbp-explicitalpha_MipMaps-1.dds"
@@ -109,6 +115,32 @@ def test_sanity_ati1_bc4u(image_path: str) -> None:
         assert_image_equal_tofile(im, TEST_FILE_ATI1.replace(".dds", ".png"))
 
 
+def test_dx10_bc2(tmp_path: Path) -> None:
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DXT3) as im:
+        im.save(out, pixel_format="BC2")
+
+    with Image.open(out) as reloaded:
+        assert reloaded.format == "DDS"
+        assert reloaded.mode == "RGBA"
+        assert reloaded.size == (256, 256)
+
+        assert_image_similar(im, reloaded, 3.81)
+
+
+def test_dx10_bc3(tmp_path: Path) -> None:
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DXT5) as im:
+        im.save(out, pixel_format="BC3")
+
+    with Image.open(out) as reloaded:
+        assert reloaded.format == "DDS"
+        assert reloaded.mode == "RGBA"
+        assert reloaded.size == (256, 256)
+
+        assert_image_similar(im, reloaded, 3.69)
+
+
 @pytest.mark.parametrize(
     "image_path",
     (
@@ -370,7 +402,7 @@ def test_not_implemented(test_file: str) -> None:
 def test_save_unsupported_mode(tmp_path: Path) -> None:
     out = str(tmp_path / "temp.dds")
     im = hopper("HSV")
-    with pytest.raises(OSError):
+    with pytest.raises(OSError, match="cannot write mode HSV as DDS"):
         im.save(out)
 
 
@@ -389,5 +421,93 @@ def test_save(mode: str, test_file: str, tmp_path: Path) -> None:
         assert im.mode == mode
         im.save(out)
 
-        with Image.open(out) as reloaded:
-            assert_image_equal(im, reloaded)
+        assert_image_equal_tofile(im, out)
+
+
+def test_save_unsupported_pixel_format(tmp_path: Path) -> None:
+    out = str(tmp_path / "temp.dds")
+    im = hopper()
+    with pytest.raises(OSError, match="cannot write pixel format UNKNOWN"):
+        im.save(out, pixel_format="UNKNOWN")
+
+
+def test_save_dxt1(tmp_path: Path) -> None:
+    # RGB
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DXT1) as im:
+        im.convert("RGB").save(out, pixel_format="DXT1")
+    assert_image_similar_tofile(im, out, 1.84)
+
+    # RGBA
+    im_alpha = im.copy()
+    im_alpha.putpixel((0, 0), (0, 0, 0, 0))
+    im_alpha.save(out, pixel_format="DXT1")
+    with Image.open(out) as reloaded:
+        assert reloaded.getpixel((0, 0)) == (0, 0, 0, 0)
+
+    # L
+    im_l = im.convert("L")
+    im_l.save(out, pixel_format="DXT1")
+    assert_image_similar_tofile(im_l.convert("RGBA"), out, 6.07)
+
+    # LA
+    im_alpha.convert("LA").save(out, pixel_format="DXT1")
+    with Image.open(out) as reloaded:
+        assert reloaded.getpixel((0, 0)) == (0, 0, 0, 0)
+
+
+def test_save_dxt3(tmp_path: Path) -> None:
+    # RGB
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DXT3) as im:
+        im_rgb = im.convert("RGB")
+    im_rgb.save(out, pixel_format="DXT3")
+    assert_image_similar_tofile(im_rgb.convert("RGBA"), out, 1.26)
+
+    # RGBA
+    im.save(out, pixel_format="DXT3")
+    assert_image_similar_tofile(im, out, 3.81)
+
+    # L
+    im_l = im.convert("L")
+    im_l.save(out, pixel_format="DXT3")
+    assert_image_similar_tofile(im_l.convert("RGBA"), out, 5.89)
+
+    # LA
+    im_la = im.convert("LA")
+    im_la.save(out, pixel_format="DXT3")
+    assert_image_similar_tofile(im_la.convert("RGBA"), out, 8.44)
+
+
+def test_save_dxt5(tmp_path: Path) -> None:
+    # RGB
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DXT1) as im:
+        im.convert("RGB").save(out, pixel_format="DXT5")
+    assert_image_similar_tofile(im, out, 1.84)
+
+    # RGBA
+    with Image.open(TEST_FILE_DXT5) as im_rgba:
+        im_rgba.save(out, pixel_format="DXT5")
+    assert_image_similar_tofile(im_rgba, out, 3.69)
+
+    # L
+    im_l = im.convert("L")
+    im_l.save(out, pixel_format="DXT5")
+    assert_image_similar_tofile(im_l.convert("RGBA"), out, 6.07)
+
+    # LA
+    im_la = im_rgba.convert("LA")
+    im_la.save(out, pixel_format="DXT5")
+    assert_image_similar_tofile(im_la.convert("RGBA"), out, 8.32)
+
+
+def test_save_dx10_bc5(tmp_path: Path) -> None:
+    out = str(tmp_path / "temp.dds")
+    with Image.open(TEST_FILE_DX10_BC5_TYPELESS) as im:
+        im.save(out, pixel_format="BC5")
+    assert_image_similar_tofile(im, out, 9.56)
+
+    im = hopper("L")
+    with pytest.raises(OSError, match="only RGB mode can be written as BC5"):
+        im.save(out, pixel_format="BC5")

setup.py

@@ -68,6 +68,7 @@ def get_version() -> str:
     "Reduce",
     "Bands",
     "BcnDecode",
+    "BcnEncode",
     "BitDecode",
     "Blend",
     "Chops",

src/PIL/DdsImagePlugin.py

@@ -419,6 +419,14 @@ def _open(self) -> None:
                     self._mode = "RGBA"
                     self.pixel_format = "BC1"
                     n = 1
+                elif dxgi_format in (DXGI_FORMAT.BC2_TYPELESS, DXGI_FORMAT.BC2_UNORM):
+                    self._mode = "RGBA"
+                    self.pixel_format = "BC2"
+                    n = 2
+                elif dxgi_format in (DXGI_FORMAT.BC3_TYPELESS, DXGI_FORMAT.BC3_UNORM):
+                    self._mode = "RGBA"
+                    self.pixel_format = "BC3"
+                    n = 3
                 elif dxgi_format in (DXGI_FORMAT.BC4_TYPELESS, DXGI_FORMAT.BC4_UNORM):
                     self._mode = "L"
                     self.pixel_format = "BC4"
@@ -518,30 +526,68 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
         msg = f"cannot write mode {im.mode} as DDS"
         raise OSError(msg)
 
-    alpha = im.mode[-1] == "A"
-    if im.mode[0] == "L":
-        pixel_flags = DDPF.LUMINANCE
-        rawmode = im.mode
-        if alpha:
-            rgba_mask = [0x000000FF, 0x000000FF, 0x000000FF]
+    flags = DDSD.CAPS | DDSD.HEIGHT | DDSD.WIDTH | DDSD.PIXELFORMAT
+    bitcount = len(im.getbands()) * 8
+    pixel_format = im.encoderinfo.get("pixel_format")
+    args: tuple[int] | str
+    if pixel_format:
+        codec_name = "bcn"
+        flags |= DDSD.LINEARSIZE
+        pitch = (im.width + 3) * 4
+        rgba_mask = [0, 0, 0, 0]
+        pixel_flags = DDPF.FOURCC
+        if pixel_format == "DXT1":
+            fourcc = D3DFMT.DXT1
+            args = (1,)
+        elif pixel_format == "DXT3":
+            fourcc = D3DFMT.DXT3
+            args = (2,)
+        elif pixel_format == "DXT5":
+            fourcc = D3DFMT.DXT5
+            args = (3,)
         else:
-            rgba_mask = [0xFF000000, 0xFF000000, 0xFF000000]
+            fourcc = D3DFMT.DX10
+            if pixel_format == "BC2":
+                args = (2,)
+                dxgi_format = DXGI_FORMAT.BC2_TYPELESS
+            elif pixel_format == "BC3":
+                args = (3,)
+                dxgi_format = DXGI_FORMAT.BC3_TYPELESS
+            elif pixel_format == "BC5":
+                args = (5,)
+                dxgi_format = DXGI_FORMAT.BC5_TYPELESS
+                if im.mode != "RGB":
+                    msg = "only RGB mode can be written as BC5"
+                    raise OSError(msg)
+            else:
+                msg = f"cannot write pixel format {pixel_format}"
+                raise OSError(msg)
     else:
-        pixel_flags = DDPF.RGB
-        rawmode = im.mode[::-1]
-        rgba_mask = [0x00FF0000, 0x0000FF00, 0x000000FF]
+        codec_name = "raw"
+        flags |= DDSD.PITCH
+        pitch = (im.width * bitcount + 7) // 8
+
+        alpha = im.mode[-1] == "A"
+        if im.mode[0] == "L":
+            pixel_flags = DDPF.LUMINANCE
+            args = im.mode
+            if alpha:
+                rgba_mask = [0x000000FF, 0x000000FF, 0x000000FF]
+            else:
+                rgba_mask = [0xFF000000, 0xFF000000, 0xFF000000]
+        else:
+            pixel_flags = DDPF.RGB
+            args = im.mode[::-1]
+            rgba_mask = [0x00FF0000, 0x0000FF00, 0x000000FF]
 
+            if alpha:
+                r, g, b, a = im.split()
+                im = Image.merge("RGBA", (a, r, g, b))
         if alpha:
-            r, g, b, a = im.split()
-            im = Image.merge("RGBA", (a, r, g, b))
-    if alpha:
-        pixel_flags |= DDPF.ALPHAPIXELS
-    rgba_mask.append(0xFF000000 if alpha else 0)
-
-    flags = DDSD.CAPS | DDSD.HEIGHT | DDSD.WIDTH | DDSD.PITCH | DDSD.PIXELFORMAT
-    bitcount = len(im.getbands()) * 8
-    pitch = (im.width * bitcount + 7) // 8
+            pixel_flags |= DDPF.ALPHAPIXELS
+        rgba_mask.append(0xFF000000 if alpha else 0)
 
+        fourcc = D3DFMT.UNKNOWN
     fp.write(
         o32(DDS_MAGIC)
         + struct.pack(
@@ -556,11 +602,16 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
         )
         + struct.pack("11I", *((0,) * 11))  # reserved
         # pfsize, pfflags, fourcc, bitcount
-        + struct.pack("<4I", 32, pixel_flags, 0, bitcount)
+        + struct.pack("<4I", 32, pixel_flags, fourcc, bitcount)
         + struct.pack("<4I", *rgba_mask)  # dwRGBABitMask
         + struct.pack("<5I", DDSCAPS.TEXTURE, 0, 0, 0, 0)
     )
-    ImageFile._save(im, fp, [ImageFile._Tile("raw", (0, 0) + im.size, 0, rawmode)])
+    if fourcc == D3DFMT.DX10:
+        fp.write(
+            # dxgi_format, 2D resource, misc, array size, straight alpha
+            struct.pack("<5I", dxgi_format, 3, 0, 0, 1)
+        )
+    ImageFile._save(im, fp, [ImageFile._Tile(codec_name, (0, 0) + im.size, 0, args)])
 
 
 def _accept(prefix: bytes) -> bool:

src/_imaging.c

@@ -4041,6 +4041,8 @@ PyImaging_ZipDecoderNew(PyObject *self, PyObject *args);
 
 /* Encoders (in encode.c) */
 extern PyObject *
+PyImaging_BcnEncoderNew(PyObject *self, PyObject *args);
+extern PyObject *
 PyImaging_EpsEncoderNew(PyObject *self, PyObject *args);
 extern PyObject *
 PyImaging_GifEncoderNew(PyObject *self, PyObject *args);
@@ -4109,6 +4111,7 @@ static PyMethodDef functions[] = {
 
     /* Codecs */
     {"bcn_decoder", (PyCFunction)PyImaging_BcnDecoderNew, METH_VARARGS},
+    {"bcn_encoder", (PyCFunction)PyImaging_BcnEncoderNew, METH_VARARGS},
     {"bit_decoder", (PyCFunction)PyImaging_BitDecoderNew, METH_VARARGS},
     {"eps_encoder", (PyCFunction)PyImaging_EpsEncoderNew, METH_VARARGS},
     {"fli_decoder", (PyCFunction)PyImaging_FliDecoderNew, METH_VARARGS},

src/encode.c

@@ -27,6 +27,7 @@
 
 #include "thirdparty/pythoncapi_compat.h"
 #include "libImaging/Imaging.h"
+#include "libImaging/Bcn.h"
 #include "libImaging/Gif.h"
 
 #ifdef HAVE_UNISTD_H
@@ -350,6 +351,31 @@ get_packer(ImagingEncoderObject *encoder, const char *mode, const char *rawmode)
     return 0;
 }
 
+/* -------------------------------------------------------------------- */
+/* BCN                                                                  */
+/* -------------------------------------------------------------------- */
+
+PyObject *
+PyImaging_BcnEncoderNew(PyObject *self, PyObject *args) {
+    ImagingEncoderObject *encoder;
+
+    char *mode;
+    int n;
+    if (!PyArg_ParseTuple(args, "si", &mode, &n)) {
+        return NULL;
+    }
+
+    encoder = PyImaging_EncoderNew(0);
+    if (encoder == NULL) {
+        return NULL;
+    }
+
+    encoder->encode = ImagingBcnEncode;
+    encoder->state.state = n;
+
+    return (PyObject *)encoder;
+}
+
 /* -------------------------------------------------------------------- */
 /* EPS                                                                  */
 /* -------------------------------------------------------------------- */