Added support for uncompressed LA images

Tests/test_file_dds.py

@@ -23,6 +23,7 @@ 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_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:
+
+    with Image.open(test_file) as im:
         assert im.format == "DDS"
-        assert im.mode == "L"
-        assert im.size == (128, 128)
+        assert im.mode == mode
+        assert im.size == size
 
-        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:
-        assert im.format == "DDS"
-        assert im.mode == "RGBA"
-        assert im.size == (800, 600)
-
-        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"),
     ],

src/PIL/DdsImagePlugin.py

@@ -136,15 +136,18 @@ class DdsImageFile(ImageFile.ImageFile):
         (bitcount,) = struct.unpack("<I", header.read(4))
         masks = struct.unpack("<4I", header.read(16))
         if pfflags & DDPF_LUMINANCE:
-            # Texture contains uncompressed L data
+            # 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 @@ class DdsImageFile(ImageFile.ImageFile):
 
 
 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
+        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):