Blender thumbnail support

tagstudio/src/qt/helpers/blender_thumbnailer.py

@@ -0,0 +1,137 @@
+#!/usr/bin/env python3
+
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+# <pep8 compliant>
+
+
+## This file is a modified script that gets the thumbnail data stored in a blend file
+
+
+import struct
+
+
+def open_wrapper_get():
+    """wrap OS specific read functionality here, fallback to 'open()'"""
+
+    def open_local_url(url, mode="r"):
+        # Redundant af, but this is where the checking of file path can be done
+
+        path = url
+
+        return open(str(path), mode)
+
+    return open_local_url
+
+
+def blend_extract_thumb(path):
+    import os
+
+    open_wrapper = open_wrapper_get()
+
+    REND = b"REND"
+    TEST = b"TEST"
+
+    blendfile = open_wrapper(path, "rb")
+
+    head = blendfile.read(12)
+
+    if head[0:2] == b"\x1f\x8b":  # gzip magic
+        import gzip
+
+        blendfile.close()
+        blendfile = gzip.GzipFile("", "rb", 0, open_wrapper(path, "rb"))
+        head = blendfile.read(12)
+
+    if not head.startswith(b"BLENDER"):
+        blendfile.close()
+        return None, 0, 0
+
+    is_64_bit = head[7] == b"-"[0]
+
+    # true for PPC, false for X86
+    is_big_endian = head[8] == b"V"[0]
+
+    # blender pre 2.5 had no thumbs
+    if head[9:11] <= b"24":
+        return None, 0, 0
+
+    sizeof_bhead = 24 if is_64_bit else 20
+    int_endian = ">i" if is_big_endian else "<i"
+    int_endian_pair = int_endian + "i"
+
+    while True:
+        bhead = blendfile.read(sizeof_bhead)
+
+        if len(bhead) < sizeof_bhead:
+            return None, 0, 0
+
+        code = bhead[:4]
+        length = struct.unpack(int_endian, bhead[4:8])[0]  # 4 == sizeof(int)
+
+        if code == REND:
+            blendfile.seek(length, os.SEEK_CUR)
+        else:
+            break
+
+    if code != TEST:
+        return None, 0, 0
+
+    try:
+        x, y = struct.unpack(int_endian_pair, blendfile.read(8))  # 8 == sizeof(int) * 2
+    except struct.error:
+        return None, 0, 0
+
+    length -= 8  # sizeof(int) * 2
+
+    if length != x * y * 4:
+        return None, 0, 0
+
+    image_buffer = blendfile.read(length)
+
+    if len(image_buffer) != length:
+        return None, 0, 0
+
+    return image_buffer, x, y
+
+
+# Trying to flip image buffer to have the image right way round on the output, but can't figure it out
+# Currently, just flipping it with ImageOps in the thumbnail_renderer.py
+
+##def flip_image(buf, width, height):
+##    import zlib
+##
+##    # reverse the vertical line order and add null bytes at the start
+##    width_byte_4 = width * 4
+##    raw_data = b"".join(b'\x00' + buf[span:span + width_byte_4] for span in range((height - 1) * width * 4, -1, - width_byte_4))
+##
+##    def png_pack(png_tag, data):
+##        chunk_head = png_tag + data
+##        return struct.pack("!I", len(data)) + chunk_head + struct.pack("!I", 0xFFFFFFFF & zlib.crc32(chunk_head))
+##
+##    return [b"".join([
+##        b'\x89PNG\r\n\x1a\n',
+##        png_pack(b'IHDR', struct.pack("!2I5B", width, height, 8, 6, 0, 0, 0)),
+##        png_pack(b'IDAT', zlib.compress(raw_data, 9)),
+##        png_pack(b'IEND', b'')]), width, height]
+
+
+def blendthumb(file_in):
+    buf, width, height = blend_extract_thumb(file_in)
+    return [buf, width, height]

tagstudio/src/qt/widgets/thumb_renderer.py

@@ -30,6 +30,7 @@
     RAW_IMAGE_TYPES,
 )
 from src.core.utils.encoding import detect_char_encoding
+from src.qt.helpers.blender_thumbnailer import blendthumb
 
 ImageFile.LOAD_TRUNCATED_IMAGES = True
 
@@ -204,6 +205,50 @@ def render(
                 # 	img_buf = io.BytesIO()
                 # 	plt.savefig(img_buf, format='png')
                 # 	image = Image.open(img_buf)
+
+                # Blender ===========================================================
+                elif _filepath.suffix.lower() == ".blend":
+                    try:
+                        blendthumbnail = blendthumb(str(_filepath))
+                        image = Image.frombuffer(
+                            "RGBA",
+                            (blendthumbnail[1], blendthumbnail[2]),
+                            blendthumbnail[0],
+                        )
+                        image = ImageOps.flip(image)
+                        image = ImageOps.exif_transpose(image)
+
+                    except (
+                        AttributeError,
+                        UnidentifiedImageError,
+                        FileNotFoundError,
+                        DecompressionBombError,
+                        UnicodeDecodeError,
+                        TypeError,
+                    ) as e:
+                        if str(e) == "expected string or buffer":
+                            logging.info(
+                                f"[ThumbRenderer]{ERROR} Can't read the blender thumbnail of {_filepath.name}. Either deleted or doesn't have a thumbnail."
+                            )
+
+                        else:
+                            logging.info(
+                                f"[ThumbRenderer]{ERROR}: Couldn't render thumbnail for {_filepath.name} ({type(e).__name__})"
+                            )
+
+                        # Making the "No blend thumbnail avaliable" thumbnail
+                        font_path = "./resources/qt/fonts/Oxanium-Bold.ttf"
+                        font = ImageFont.truetype(font_path, 17)
+                        bg = Image.new("RGB", (256, 256), color="#1e1e1e")
+                        draw = ImageDraw.Draw(bg)
+                        draw.text(
+                            (16, 16),
+                            "Can't read blend thumbnail",
+                            file=(255, 255, 255),
+                            font=font,
+                        )
+                        image = bg
+
                 # No Rendered Thumbnail ========================================
                 else:
                     image = ThumbRenderer.thumb_file_default_512.resize(