Added automatic PNG resizing solver

aperisolve/analyzers/image_resize.py

@@ -0,0 +1,189 @@
+"""Image size bruteforcer for common PNG sizes."""
+
+import zlib
+from pathlib import Path
+from .utils import update_data
+
+# Full list of expected sizes
+EXPECTED_SIZES = [
+    # -------------------------
+    # ICONS (Square)
+    # -------------------------
+    (16, 16), (20, 20), (24, 24), (28, 28),
+    (32, 32), (48, 48), (64, 64), (72, 72),
+    (96, 96), (128, 128), (192, 192), (256, 256),
+    (384, 384), (512, 512), (768, 768), (1024, 1024),
+    (1536, 1536), (2048, 2048), (4096, 4096),
+
+    # -------------------------
+    # 1:1 Square (General)
+    # -------------------------
+    (300, 300), (500, 500), (800, 800), (1000, 1000),
+    (1500, 1500), (2000, 2000), (2500, 2500), (3000, 3000),
+
+    # -------------------------
+    # 4:3 Aspect (Classic Screens)
+    # -------------------------
+    (320, 240), (640, 480), (800, 600), (960, 720),
+    (1024, 768), (1280, 960), (1600, 1200), (2048, 1536),
+    (2560, 1920), (3200, 2400), (4096, 3072),
+
+    # -------------------------
+    # 3:2 Aspect (Photography)
+    # -------------------------
+    (600, 400), (900, 600), (1200, 800), (1500, 1000),
+    (1800, 1200), (2400, 1600), (3000, 2000), (3600, 2400),
+    (4500, 3000), (6000, 4000),
+
+    # -------------------------
+    # 16:9 Aspect (Video / Web)
+    # -------------------------
+    (426, 240), (640, 360), (854, 480), (960, 540),
+    (1280, 720), (1366, 768), (1600, 900), (1920, 1080),
+    (2560, 1440), (3200, 1800), (3440, 1935), (3840, 2160),
+    (5120, 2880), (7680, 4320), (10240, 5760),
+
+    # -------------------------
+    # 16:10 Aspect (Laptops)
+    # -------------------------
+    (1280, 800), (1440, 900), (1680, 1050),
+    (1920, 1200), (2560, 1600), (2880, 1800),
+    (3840, 2400), (5120, 3200),
+
+    # -------------------------
+    # Mobile Portrait (9:16)
+    # -------------------------
+    (720, 1280), (1080, 1920), (1440, 2560),
+    (2160, 3840), (1440, 2960), (1080, 2400),
+    (1170, 2532), (1284, 2778), (1290, 2796),
+
+    # -------------------------
+    # Social Media Sizes
+    # -------------------------
+    # Instagram
+    (1080, 1080), (1080, 1350), (1080, 1920),
+
+    # Facebook
+    (1200, 628), (1200, 1200),
+
+    # Twitter/X
+    (1200, 675), (1500, 500),
+
+    # YouTube Thumbnails
+    (1280, 720), (1920, 1080),
+
+    # -------------------------
+    # Banners / Headers
+    # -------------------------
+    (1600, 500), (1920, 500), (2560, 700),
+    (3000, 1000), (3840, 1200),
+
+    # -------------------------
+    # Print-like Digital Sizes
+    # -------------------------
+    (2550, 3300),  # Letter @ 300 DPI
+    (2480, 3508),  # A4 @ 300 DPI
+    (3508, 4961),  # A3 @ 300 DPI
+    (4961, 7016),  # A2 @ 300 DPI
+    (7016, 9933),  # A1 @ 300 DPI
+
+]
+
+def calc_checksum(header_chunk, width_bytes, height_bytes):
+    """
+    Calculates the CRC32 of the IHDR chunk with new dimensions.
+    header_chunk: The full IHDR chunk (Type + Data).
+    """
+    # Reconstruct IHDR: [Type(4)] + [New Width(4)] + [New Height(4)] + [Rest of Data(5)]
+    new_header = header_chunk[:4] + width_bytes + height_bytes + header_chunk[12:]
+
+    # Calculate CRC and return as 4 bytes (Big Endian)
+    return bytearray((zlib.crc32(new_header) & 0xffffffff).to_bytes(4, byteorder='big'))
+
+def analyze_image_resize(input_img: Path, output_dir: Path) -> None:
+    """
+    Analyze an image submission using python-based resize bruteforce.
+    Attempts to recover PNGs with modified resolutions but valid CRCs.
+    """
+
+    # 1. Setup Paths
+    input_img = Path(input_img)
+    output_dir = Path(output_dir)
+    extracted_dir = output_dir / "image_resize_output_dir"
+
+    # 2. CREATE THE DIRECTORY (Crucial Step!)
+    extracted_dir.mkdir(parents=True, exist_ok=True)
+
+    # 3. Initialize Logs
+    logs = []
+    recovered_images = []
+
+    try:
+        with open(input_img, "rb") as image:
+            f = image.read()
+            b = bytearray(f)
+
+            # Find IHDR start
+            IHDR = b.find(b'\x49\x48\x44\x52')
+            if IHDR == -1:
+                logs.append("Failure: PNG header (IHDR) not found.")
+                update_data(output_dir, {"image_resize": {"status": "error", "error": "PNG header not found."}})
+                return
+
+            # Calculate Chunk Length (The 4 bytes BEFORE IHDR tag)
+            chunk_length = int.from_bytes((b[IHDR- 4: IHDR]), byteorder="big") + 4
+
+            # Extract Target CRC (The 4 bytes AFTER the chunk data)
+            target_crc = b[IHDR + chunk_length:IHDR + chunk_length + 4]
+
+            # Isolate the header chunk (Type + Data)
+            header_chunk = b[IHDR:IHDR + chunk_length]
+
+            logs.append(f"Target CRC found: 0x{target_crc.hex()}")
+
+            match_found = False
+
+            # Brute-force Loop
+            for size in EXPECTED_SIZES:
+                width, height = size
+
+                # Convert dimensions to 4-byte Big Endian arrays
+                width_bytes = bytearray(width.to_bytes(4, byteorder='big'))
+                height_bytes = bytearray(height.to_bytes(4, byteorder='big'))
+
+                # Check if this size matches the file's CRC
+                if target_crc == calc_checksum(header_chunk, width_bytes, height_bytes):
+                    match_found = True
+                    logs.append(f"Success: Match found! Dimensions: {width}x{height}")
+
+                    # Create Output Filename
+                    output_filename = f"recovered_{width}x{height}.png"
+                    output_path = extracted_dir / output_filename
+
+                    # Splicing: [Start...IHDR+4] + [W] + [H] + [IHDR+12...End]
+                    full_png_data = b[:IHDR+4] + width_bytes + height_bytes + b[IHDR+12:]
+
+                    # Write the recovered file to disk
+                    with open(output_path, "wb") as out_f:
+                        out_f.write(full_png_data)
+
+                    recovered_images.append(output_filename)
+                    break # Stop looking after finding the match
+
+            if not match_found:
+                logs.append("Failure: No matching dimensions found.")
+
+        # 4. Final Data Update
+        output_data = {
+            "image_resize": {  # Key name must match your module name in AperiSolve
+                "status": "ok",
+                "output": logs,
+                "images": recovered_images, # Tells frontend to display the image
+            }
+        }
+        update_data(output_dir, output_data)
+
+    except Exception as e:
+        update_data(output_dir, {"image_resize": {"status": "error", "error": str(e)}})
+
+    return None