Merge pull request #7956 from Cirras/obscure-bitmap-headers

Add support for reading `BITMAPV2INFOHEADER` and `BITMAPV3INFOHEADER`

Tests/test_bmp_reference.py

@@ -44,6 +44,9 @@ def test_questionable() -> None:
         "pal8os2sp.bmp",
         "pal8rletrns.bmp",
         "rgb32bf-xbgr.bmp",
+        "rgba32.bmp",
+        "rgb32h52.bmp",
+        "rgba32h56.bmp",
     ]
     for f in get_files("q"):
         try:

Tests/test_file_bmp.py

@@ -5,7 +5,7 @@
 
 import pytest
 
-from PIL import BmpImagePlugin, Image
+from PIL import BmpImagePlugin, Image, _binary
 
 from .helper import (
     assert_image_equal,
@@ -128,6 +128,29 @@ def test_load_dib() -> None:
         assert_image_equal_tofile(im, "Tests/images/clipboard_target.png")
 
 
+@pytest.mark.parametrize(
+    "header_size, path",
+    (
+        (12, "g/pal8os2.bmp"),
+        (40, "g/pal1.bmp"),
+        (52, "q/rgb32h52.bmp"),
+        (56, "q/rgba32h56.bmp"),
+        (64, "q/pal8os2v2.bmp"),
+        (108, "g/pal8v4.bmp"),
+        (124, "g/pal8v5.bmp"),
+    ),
+)
+def test_dib_header_size(header_size, path):
+    image_path = "Tests/images/bmp/" + path
+    with open(image_path, "rb") as fp:
+        data = fp.read()[14:]
+    assert _binary.i32le(data) == header_size
+
+    dib = io.BytesIO(data)
+    with Image.open(dib) as im:
+        im.load()
+
+
 def test_save_dib(tmp_path: Path) -> None:
     outfile = str(tmp_path / "temp.dib")
 

src/PIL/BmpImagePlugin.py

@@ -53,7 +53,7 @@ def _accept(prefix: bytes) -> bool:
 
 
 def _dib_accept(prefix):
-    return i32(prefix) in [12, 40, 64, 108, 124]
+    return i32(prefix) in [12, 40, 52, 56, 64, 108, 124]
 
 
 # =============================================================================
@@ -83,8 +83,9 @@ def _bitmap(self, header=0, offset=0):
         # read the rest of the bmp header, without its size
         header_data = ImageFile._safe_read(self.fp, file_info["header_size"] - 4)
 
-        # -------------------------------------------------- IBM OS/2 Bitmap v1
+        # ------------------------------- Windows Bitmap v2, IBM OS/2 Bitmap v1
         # ----- This format has different offsets because of width/height types
+        # 12: BITMAPCOREHEADER/OS21XBITMAPHEADER
         if file_info["header_size"] == 12:
             file_info["width"] = i16(header_data, 0)
             file_info["height"] = i16(header_data, 2)
@@ -93,9 +94,14 @@ def _bitmap(self, header=0, offset=0):
             file_info["compression"] = self.RAW
             file_info["palette_padding"] = 3
 
-        # --------------------------------------------- Windows Bitmap v2 to v5
-        # v3, OS/2 v2, v4, v5
-        elif file_info["header_size"] in (40, 64, 108, 124):
+        # --------------------------------------------- Windows Bitmap v3 to v5
+        #  40: BITMAPINFOHEADER
+        #  52: BITMAPV2HEADER
+        #  56: BITMAPV3HEADER
+        #  64: BITMAPCOREHEADER2/OS22XBITMAPHEADER
+        # 108: BITMAPV4HEADER
+        # 124: BITMAPV5HEADER
+        elif file_info["header_size"] in (40, 52, 56, 64, 108, 124):
             file_info["y_flip"] = header_data[7] == 0xFF
             file_info["direction"] = 1 if file_info["y_flip"] else -1
             file_info["width"] = i32(header_data, 0)
@@ -117,10 +123,13 @@ def _bitmap(self, header=0, offset=0):
             file_info["palette_padding"] = 4
             self.info["dpi"] = tuple(x / 39.3701 for x in file_info["pixels_per_meter"])
             if file_info["compression"] == self.BITFIELDS:
-                if len(header_data) >= 52:
-                    for idx, mask in enumerate(
-                        ["r_mask", "g_mask", "b_mask", "a_mask"]
-                    ):
+                masks = ["r_mask", "g_mask", "b_mask"]
+                if len(header_data) >= 48:
+                    if len(header_data) >= 52:
+                        masks.append("a_mask")
+                    else:
+                        file_info["a_mask"] = 0x0
+                    for idx, mask in enumerate(masks):
                         file_info[mask] = i32(header_data, 36 + idx * 4)
                 else:
                     # 40 byte headers only have the three components in the
@@ -132,7 +141,7 @@ def _bitmap(self, header=0, offset=0):
                     # location, but it is listed as a reserved component,
                     # and it is not generally an alpha channel
                     file_info["a_mask"] = 0x0
-                    for mask in ["r_mask", "g_mask", "b_mask"]:
+                    for mask in masks:
                         file_info[mask] = i32(read(4))
                 file_info["rgb_mask"] = (
                     file_info["r_mask"],
@@ -175,9 +184,11 @@ def _bitmap(self, header=0, offset=0):
                 32: [
                     (0xFF0000, 0xFF00, 0xFF, 0x0),
                     (0xFF000000, 0xFF0000, 0xFF00, 0x0),
+                    (0xFF000000, 0xFF00, 0xFF, 0x0),
                     (0xFF000000, 0xFF0000, 0xFF00, 0xFF),
                     (0xFF, 0xFF00, 0xFF0000, 0xFF000000),
                     (0xFF0000, 0xFF00, 0xFF, 0xFF000000),
+                    (0xFF000000, 0xFF00, 0xFF, 0xFF0000),
                     (0x0, 0x0, 0x0, 0x0),
                 ],
                 24: [(0xFF0000, 0xFF00, 0xFF)],
@@ -186,9 +197,11 @@ def _bitmap(self, header=0, offset=0):
             MASK_MODES = {
                 (32, (0xFF0000, 0xFF00, 0xFF, 0x0)): "BGRX",
                 (32, (0xFF000000, 0xFF0000, 0xFF00, 0x0)): "XBGR",
+                (32, (0xFF000000, 0xFF00, 0xFF, 0x0)): "BGXR",
                 (32, (0xFF000000, 0xFF0000, 0xFF00, 0xFF)): "ABGR",
                 (32, (0xFF, 0xFF00, 0xFF0000, 0xFF000000)): "RGBA",
                 (32, (0xFF0000, 0xFF00, 0xFF, 0xFF000000)): "BGRA",
+                (32, (0xFF000000, 0xFF00, 0xFF, 0xFF0000)): "BGAR",
                 (32, (0x0, 0x0, 0x0, 0x0)): "BGRA",
                 (24, (0xFF0000, 0xFF00, 0xFF)): "BGR",
                 (16, (0xF800, 0x7E0, 0x1F)): "BGR;16",

src/libImaging/Unpack.c

@@ -790,6 +790,17 @@ ImagingUnpackBGRX(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+ImagingUnpackBGXR(UINT8 *_out, const UINT8 *in, int pixels) {
+    int i;
+    for (i = 0; i < pixels; i++) {
+        UINT32 iv = MAKE_UINT32(in[3], in[1], in[0], 255);
+        memcpy(_out, &iv, sizeof(iv));
+        in += 4;
+        _out += 4;
+    }
+}
+
 static void
 ImagingUnpackXRGB(UINT8 *_out, const UINT8 *in, int pixels) {
     int i;
@@ -1090,6 +1101,17 @@ unpackBGRA16B(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+unpackBGAR(UINT8 *_out, const UINT8 *in, int pixels) {
+    int i;
+    for (i = 0; i < pixels; i++) {
+        UINT32 iv = MAKE_UINT32(in[3], in[1], in[0], in[2]);
+        memcpy(_out, &iv, sizeof(iv));
+        in += 4;
+        _out += 4;
+    }
+}
+
 /* Unpack to "CMYK" image */
 
 static void
@@ -1584,6 +1606,7 @@ static struct {
     {"RGB", "RGBA;L", 32, unpackRGBAL},
     {"RGB", "RGBA;15", 16, ImagingUnpackRGBA15},
     {"RGB", "BGRX", 32, ImagingUnpackBGRX},
+    {"RGB", "BGXR", 32, ImagingUnpackBGXR},
     {"RGB", "XRGB", 32, ImagingUnpackXRGB},
     {"RGB", "XBGR", 32, ImagingUnpackXBGR},
     {"RGB", "YCC;P", 24, ImagingUnpackYCC},
@@ -1624,6 +1647,7 @@ static struct {
     {"RGBA", "BGRA", 32, unpackBGRA},
     {"RGBA", "BGRA;16L", 64, unpackBGRA16L},
     {"RGBA", "BGRA;16B", 64, unpackBGRA16B},
+    {"RGBA", "BGAR", 32, unpackBGAR},
     {"RGBA", "ARGB", 32, unpackARGB},
     {"RGBA", "ABGR", 32, unpackABGR},
     {"RGBA", "YCCA;P", 32, ImagingUnpackYCCA},