lightweight dimensions detectors for pictures

requirements.txt

@@ -6,4 +6,3 @@ waitress
 flask-login
 pysqlite3
 psutil
-pillow

src/util/UtilPicture.py

@@ -1,8 +1,133 @@
 import struct
-from PIL import Image
+import imghdr
+import os
+
+
+def get_png_size(file):
+    file.seek(16)
+    width, height = struct.unpack('>ii', file.read(8))
+    return width, height
+
+
+def get_jpeg_size(file):
+    file.seek(0)
+    size = 2
+    ftype = 0
+    while not 0xC0 <= ftype <= 0xCF:
+        file.seek(size, 1)
+        byte = file.read(1)
+        while ord(byte) == 0xFF:
+            byte = file.read(1)
+        ftype = ord(byte)
+        size = struct.unpack('>H', file.read(2))[0] - 2
+    file.seek(1, 1)
+    height, width = struct.unpack('>HH', file.read(4))
+    return width, height
+
+
+def get_gif_size(file):
+    file.seek(6)
+    width, height = struct.unpack('<HH', file.read(4))
+    return width, height
+
+
+def get_webp_size(file):
+    file.seek(12)
+    chunk_header = file.read(8)
+    while chunk_header:
+        chunk_size = struct.unpack('<I', chunk_header[4:])[0]
+        if chunk_header[0:4] == b'VP8 ':
+            vp8_header = file.read(10)
+            width, height = struct.unpack('<HH', vp8_header[6:10])
+            return width, height
+        elif chunk_header[0:4] == b'VP8L':
+            vp8l_header = file.read(5)
+            b1, b2, b3, b4 = struct.unpack('<BBBB', vp8l_header[1:])
+            width = (b1 | ((b2 & 0x3F) << 8)) + 1
+            height = ((b2 >> 6) | (b3 << 2) | ((b4 & 0x0F) << 10)) + 1
+            return width, height
+        elif chunk_header[0:4] == b'VP8X':
+            vp8x_header = file.read(10)
+            width, height = struct.unpack('<HH', vp8x_header[4:8])
+            width = (width + 1) & 0xFFFFFF
+            height = (height + 1) & 0xFFFFFF
+            return width, height
+        else:
+            file.seek(chunk_size, 1)
+        chunk_header = file.read(8)
+    raise ValueError("Not a valid WebP file")
+
+
+def get_bmp_size(file):
+    file.seek(18)
+    width, height = struct.unpack('<ii', file.read(8))
+    return width, height
+
+
+def get_tiff_size(file):
+    file.seek(0)
+    byte_order = file.read(2)
+    if byte_order == b'II':
+        endian = '<'
+    elif byte_order == b'MM':
+        endian = '>'
+    else:
+        raise ValueError("Not a valid TIFF file")
+
+    file.seek(4)
+    offset = struct.unpack(endian + 'I', file.read(4))[0]
+    file.seek(offset)
+
+    while True:
+        num_tags = struct.unpack(endian + 'H', file.read(2))[0]
+        for _ in range(num_tags):
+            tag = file.read(12)
+            if struct.unpack(endian + 'H', tag[:2])[0] == 256:
+                width = struct.unpack(endian + 'I', tag[8:])[0]
+            elif struct.unpack(endian + 'H', tag[:2])[0] == 257:
+                height = struct.unpack(endian + 'I', tag[8:])[0]
+        next_ifd_offset = struct.unpack(endian + 'I', file.read(4))[0]
+        if next_ifd_offset == 0:
+            break
+        file.seek(next_ifd_offset)
+    return width, height
+
+
+def get_ico_size(file):
+    file.seek(6)
+    num_images = struct.unpack('<H', file.read(2))[0]
+    largest_size = (0, 0)
+    for _ in range(num_images):
+        width, height = struct.unpack('<BB', file.read(2))
+        width = width if width != 0 else 256
+        height = height if height != 0 else 256
+        if width * height > largest_size[0] * largest_size[1]:
+            largest_size = (width, height)
+        file.seek(14, 1)  # Skip over the rest of the directory entry
+    return largest_size
 
 
 def get_picture_metadata(image_path):
-    with Image.open(image_path) as img:
-        width, height = img.size
-        return width, height
+    # Determine the image type using imghdr and file extension as a fallback
+    img_type = imghdr.what(image_path)
+    if not img_type:
+        _, ext = os.path.splitext(image_path)
+        img_type = ext.lower().replace('.', '')
+
+    with open(image_path, 'rb') as file:
+        if img_type == 'png':
+            return get_png_size(file)
+        elif img_type == 'jpeg' or img_type == 'jpg':
+            return get_jpeg_size(file)
+        elif img_type == 'gif':
+            return get_gif_size(file)
+        elif img_type == 'webp':
+            return get_webp_size(file)
+        elif img_type == 'bmp':
+            return get_bmp_size(file)
+        elif img_type == 'tiff' or img_type == 'tif':
+            return get_tiff_size(file)
+        elif img_type == 'ico':
+            return get_ico_size(file)
+        else:
+            raise ValueError("Unsupported image format or corrupted file")