From 9e6a7d974084a4d7b6be9d68b732558194d20e51 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 23 Dec 2022 17:43:18 +1100
Subject: [PATCH 1/4] Added support for uncompressed L images

---
 Tests/images/uncompressed_l.dds | Bin 0 -> 16512 bytes
 Tests/images/uncompressed_l.png | Bin 0 -> 861 bytes
 Tests/test_file_dds.py          |  12 +++++++++--
 src/PIL/DdsImagePlugin.py       |  35 ++++++++++++++++++++++++--------
 4 files changed, 36 insertions(+), 11 deletions(-)
 create mode 100644 Tests/images/uncompressed_l.dds
 create mode 100644 Tests/images/uncompressed_l.png

diff --git a/Tests/images/uncompressed_l.dds b/Tests/images/uncompressed_l.dds
new file mode 100644
index 0000000000000000000000000000000000000000..b82282587ec30665fceafced278f1c59b3402ed1
GIT binary patch
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diff --git a/Tests/images/uncompressed_l.png b/Tests/images/uncompressed_l.png
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diff --git a/Tests/test_file_dds.py b/Tests/test_file_dds.py
index 4b9f8949ef5..f579cd1c257 100644
--- a/Tests/test_file_dds.py
+++ b/Tests/test_file_dds.py
@@ -22,6 +22,7 @@
 TEST_FILE_DX10_BC7_UNORM_SRGB = "Tests/images/DXGI_FORMAT_BC7_UNORM_SRGB.dds"
 TEST_FILE_DX10_R8G8B8A8 = "Tests/images/argb-32bpp_MipMaps-1.dds"
 TEST_FILE_DX10_R8G8B8A8_UNORM_SRGB = "Tests/images/DXGI_FORMAT_R8G8B8A8_UNORM_SRGB.dds"
+TEST_FILE_UNCOMPRESSED_L = "Tests/images/uncompressed_l.dds"
 TEST_FILE_UNCOMPRESSED_RGB = "Tests/images/hopper.dds"
 TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA = "Tests/images/uncompressed_rgb.dds"
 
@@ -194,8 +195,14 @@ def test_unimplemented_dxgi_format():
             pass
 
 
-def test_uncompressed_rgb():
-    """Check uncompressed RGB images can be opened"""
+def test_uncompressed():
+    """Check uncompressed images can be opened"""
+    with Image.open(TEST_FILE_UNCOMPRESSED_L) as im:
+        assert im.format == "DDS"
+        assert im.mode == "L"
+        assert im.size == (128, 128)
+
+        assert_image_equal_tofile(im, "Tests/images/uncompressed_l.png")
 
     # convert -format dds -define dds:compression=none hopper.jpg hopper.dds
     with Image.open(TEST_FILE_UNCOMPRESSED_RGB) as im:
@@ -305,6 +312,7 @@ def test_save_unsupported_mode(tmp_path):
 @pytest.mark.parametrize(
     ("mode", "test_file"),
     [
+        ("L", "Tests/images/linear_gradient.png"),
         ("RGB", "Tests/images/hopper.png"),
         ("RGBA", "Tests/images/pil123rgba.png"),
     ],
diff --git a/src/PIL/DdsImagePlugin.py b/src/PIL/DdsImagePlugin.py
index eea6e31534c..b78cc649f13 100644
--- a/src/PIL/DdsImagePlugin.py
+++ b/src/PIL/DdsImagePlugin.py
@@ -135,7 +135,12 @@ def _open(self):
         fourcc = header.read(4)
         (bitcount,) = struct.unpack("<I", header.read(4))
         masks = struct.unpack("<4I", header.read(16))
-        if pfflags & DDPF_RGB:
+        if pfflags & DDPF_LUMINANCE:
+            # Texture contains uncompressed L data
+            self.mode = "L"
+
+            self.tile = [("raw", (0, 0) + self.size, 0, ("L", 0, 1))]
+        elif pfflags & DDPF_RGB:
             # Texture contains uncompressed RGB data
             masks = {mask: ["R", "G", "B", "A"][i] for i, mask in enumerate(masks)}
             rawmode = ""
@@ -223,9 +228,24 @@ def load_seek(self, pos):
 
 
 def _save(im, fp, filename):
-    if im.mode not in ("RGB", "RGBA"):
+    if im.mode not in ("RGB", "RGBA", "L"):
         raise OSError(f"cannot write mode {im.mode} as DDS")
 
+    if im.mode == "L":
+        masks = [0xFF000000]
+        pixel_flags = DDPF_LUMINANCE
+    else:
+        masks = [0xFF0000, 0xFF00, 0xFF]
+        if im.mode == "RGBA":
+            pixel_flags = DDS_RGBA
+            masks.append(0xFF000000)
+        else:
+            pixel_flags = DDPF_RGB
+
+    bitcount = len(masks) * 8
+    while len(masks) < 4:
+        masks.append(0)
+
     fp.write(
         o32(DDS_MAGIC)
         + o32(124)  # header size
@@ -234,18 +254,15 @@ def _save(im, fp, filename):
         )  # flags
         + o32(im.height)
         + o32(im.width)
-        + o32((im.width * (32 if im.mode == "RGBA" else 24) + 7) // 8)  # pitch
+        + o32((im.width * bitcount + 7) // 8)  # pitch
         + o32(0)  # depth
         + o32(0)  # mipmaps
         + o32(0) * 11  # reserved
         + o32(32)  # pfsize
-        + o32(DDS_RGBA if im.mode == "RGBA" else DDPF_RGB)  # pfflags
+        + o32(pixel_flags)  # pfflags
         + o32(0)  # fourcc
-        + o32(32 if im.mode == "RGBA" else 24)  # bitcount
-        + o32(0xFF0000)  # rbitmask
-        + o32(0xFF00)  # gbitmask
-        + o32(0xFF)  # bbitmask
-        + o32(0xFF000000 if im.mode == "RGBA" else 0)  # abitmask
+        + o32(bitcount)  # bitcount
+        + b"".join(o32(mask) for mask in masks)  # rgbabitmask
         + o32(DDSCAPS_TEXTURE)  # dwCaps
         + o32(0)  # dwCaps2
         + o32(0)  # dwCaps3

From 582b63100109c951d146276c51a2d7d90e2ac125 Mon Sep 17 00:00:00 2001
From: REDxEYE <med45c@gmail.com>
Date: Mon, 8 Aug 2022 02:24:55 +0300
Subject: [PATCH 2/4] Add missing LA test textures

---
 Tests/images/la.dds | Bin 0 -> 32896 bytes
 Tests/images/la.png | Bin 0 -> 1060 bytes
 2 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 Tests/images/la.dds
 create mode 100644 Tests/images/la.png

diff --git a/Tests/images/la.dds b/Tests/images/la.dds
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From dcf3d0bee2db0ee8b410f6c6355550a2a2a608a2 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 23 Dec 2022 19:07:45 +1100
Subject: [PATCH 3/4] Added support for uncompressed LA images

---
 Tests/images/{la.dds => uncompressed_la.dds} | Bin
 Tests/images/{la.png => uncompressed_la.png} | Bin
 Tests/test_file_dds.py                       |  38 ++++++++-----------
 src/PIL/DdsImagePlugin.py                    |  31 ++++++++-------
 4 files changed, 33 insertions(+), 36 deletions(-)
 rename Tests/images/{la.dds => uncompressed_la.dds} (100%)
 rename Tests/images/{la.png => uncompressed_la.png} (100%)

diff --git a/Tests/images/la.dds b/Tests/images/uncompressed_la.dds
similarity index 100%
rename from Tests/images/la.dds
rename to Tests/images/uncompressed_la.dds
diff --git a/Tests/images/la.png b/Tests/images/uncompressed_la.png
similarity index 100%
rename from Tests/images/la.png
rename to Tests/images/uncompressed_la.png
diff --git a/Tests/test_file_dds.py b/Tests/test_file_dds.py
index f579cd1c257..cac4108a8f0 100644
--- a/Tests/test_file_dds.py
+++ b/Tests/test_file_dds.py
@@ -23,6 +23,7 @@
 TEST_FILE_DX10_R8G8B8A8 = "Tests/images/argb-32bpp_MipMaps-1.dds"
 TEST_FILE_DX10_R8G8B8A8_UNORM_SRGB = "Tests/images/DXGI_FORMAT_R8G8B8A8_UNORM_SRGB.dds"
 TEST_FILE_UNCOMPRESSED_L = "Tests/images/uncompressed_l.dds"
+TEST_FILE_UNCOMPRESSED_L_WITH_ALPHA = "Tests/images/uncompressed_la.dds"
 TEST_FILE_UNCOMPRESSED_RGB = "Tests/images/hopper.dds"
 TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA = "Tests/images/uncompressed_rgb.dds"
 
@@ -195,32 +196,24 @@ def test_unimplemented_dxgi_format():
             pass
 
 
-def test_uncompressed():
+@pytest.mark.parametrize(
+    ("mode", "size", "test_file"),
+    [
+        ("L", (128, 128), TEST_FILE_UNCOMPRESSED_L),
+        ("LA", (128, 128), TEST_FILE_UNCOMPRESSED_L_WITH_ALPHA),
+        ("RGB", (128, 128), TEST_FILE_UNCOMPRESSED_RGB),
+        ("RGBA", (800, 600), TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA),
+    ],
+)
+def test_uncompressed(mode, size, test_file):
     """Check uncompressed images can be opened"""
-    with Image.open(TEST_FILE_UNCOMPRESSED_L) as im:
-        assert im.format == "DDS"
-        assert im.mode == "L"
-        assert im.size == (128, 128)
-
-        assert_image_equal_tofile(im, "Tests/images/uncompressed_l.png")
-
-    # convert -format dds -define dds:compression=none hopper.jpg hopper.dds
-    with Image.open(TEST_FILE_UNCOMPRESSED_RGB) as im:
-        assert im.format == "DDS"
-        assert im.mode == "RGB"
-        assert im.size == (128, 128)
 
-        assert_image_equal_tofile(im, "Tests/images/hopper.png")
-
-    # Test image with alpha
-    with Image.open(TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA) as im:
+    with Image.open(test_file) as im:
         assert im.format == "DDS"
-        assert im.mode == "RGBA"
-        assert im.size == (800, 600)
+        assert im.mode == mode
+        assert im.size == size
 
-        assert_image_equal_tofile(
-            im, TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA.replace(".dds", ".png")
-        )
+        assert_image_equal_tofile(im, test_file.replace(".dds", ".png"))
 
 
 def test__accept_true():
@@ -313,6 +306,7 @@ def test_save_unsupported_mode(tmp_path):
     ("mode", "test_file"),
     [
         ("L", "Tests/images/linear_gradient.png"),
+        ("LA", "Tests/images/uncompressed_la.png"),
         ("RGB", "Tests/images/hopper.png"),
         ("RGBA", "Tests/images/pil123rgba.png"),
     ],
diff --git a/src/PIL/DdsImagePlugin.py b/src/PIL/DdsImagePlugin.py
index b78cc649f13..f78c8b17cbd 100644
--- a/src/PIL/DdsImagePlugin.py
+++ b/src/PIL/DdsImagePlugin.py
@@ -136,15 +136,18 @@ def _open(self):
         (bitcount,) = struct.unpack("<I", header.read(4))
         masks = struct.unpack("<4I", header.read(16))
         if pfflags & DDPF_LUMINANCE:
-            # Texture contains uncompressed L data
-            self.mode = "L"
+            # Texture contains uncompressed L or LA data
+            if pfflags & DDPF_ALPHAPIXELS:
+                self.mode = "LA"
+            else:
+                self.mode = "L"
 
-            self.tile = [("raw", (0, 0) + self.size, 0, ("L", 0, 1))]
+            self.tile = [("raw", (0, 0) + self.size, 0, (self.mode, 0, 1))]
         elif pfflags & DDPF_RGB:
             # Texture contains uncompressed RGB data
             masks = {mask: ["R", "G", "B", "A"][i] for i, mask in enumerate(masks)}
             rawmode = ""
-            if bitcount == 32:
+            if pfflags & DDPF_ALPHAPIXELS:
                 rawmode += masks[0xFF000000]
             else:
                 self.mode = "RGB"
@@ -228,19 +231,19 @@ def load_seek(self, pos):
 
 
 def _save(im, fp, filename):
-    if im.mode not in ("RGB", "RGBA", "L"):
+    if im.mode not in ("RGB", "RGBA", "L", "LA"):
         raise OSError(f"cannot write mode {im.mode} as DDS")
 
-    if im.mode == "L":
-        masks = [0xFF000000]
+    rawmode = im.mode
+    masks = [0xFF0000, 0xFF00, 0xFF]
+    if im.mode in ("L", "LA"):
         pixel_flags = DDPF_LUMINANCE
     else:
-        masks = [0xFF0000, 0xFF00, 0xFF]
-        if im.mode == "RGBA":
-            pixel_flags = DDS_RGBA
-            masks.append(0xFF000000)
-        else:
-            pixel_flags = DDPF_RGB
+        pixel_flags = DDPF_RGB
+        rawmode = rawmode[::-1]
+    if im.mode in ("LA", "RGBA"):
+        pixel_flags |= DDPF_ALPHAPIXELS
+        masks.append(0xFF000000)
 
     bitcount = len(masks) * 8
     while len(masks) < 4:
@@ -272,7 +275,7 @@ def _save(im, fp, filename):
     if im.mode == "RGBA":
         r, g, b, a = im.split()
         im = Image.merge("RGBA", (a, r, g, b))
-    ImageFile._save(im, fp, [("raw", (0, 0) + im.size, 0, (im.mode[::-1], 0, 1))])
+    ImageFile._save(im, fp, [("raw", (0, 0) + im.size, 0, (rawmode, 0, 1))])
 
 
 def _accept(prefix):

From 941a2d60b28c32f1193ef2f9627fc80f9279802d Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sat, 24 Dec 2022 08:41:57 +1100
Subject: [PATCH 4/4] Added release notes

---
 docs/releasenotes/9.4.0.rst | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/docs/releasenotes/9.4.0.rst b/docs/releasenotes/9.4.0.rst
index ccbe62a6bcd..0068f281608 100644
--- a/docs/releasenotes/9.4.0.rst
+++ b/docs/releasenotes/9.4.0.rst
@@ -70,7 +70,8 @@ TODO
 Other Changes
 =============
 
-TODO
-^^^^
+Added support for DDS L and LA images
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-TODO
+Support has been added to read and write L and LA DDS images in the uncompressed
+format, known as "luminance" textures.