Add multi-page PDF support: process up to 5 pages and combine vertically

pdf_comparator.py

@@ -114,7 +114,7 @@ def normalize_token(token: str) -> str:
 def _is_pdf(path: str) -> bool:
     return os.path.splitext(path.lower())[1] == ".pdf"
 
-def load_first_page(path: str, dpi: int = 300) -> Image.Image:
+def load_pdf_pages(path: str, dpi: int = 300, max_pages: int = 5) -> List[Image.Image]:
     if _is_pdf(path):
         # Try pdf2image with multiple poppler paths first
         poppler_paths = ["/usr/bin", "/usr/local/bin", "/bin", None]
@@ -122,14 +122,14 @@ def load_first_page(path: str, dpi: int = 300) -> Image.Image:
         for poppler_path in poppler_paths:
             try:
                 if poppler_path:
-                    imgs = convert_from_path(path, dpi=dpi, first_page=1, last_page=1, poppler_path=poppler_path)
+                    imgs = convert_from_path(path, dpi=dpi, first_page=1, last_page=max_pages, poppler_path=poppler_path)
                 else:
-                    imgs = convert_from_path(path, dpi=dpi, first_page=1, last_page=1)
+                    imgs = convert_from_path(path, dpi=dpi, first_page=1, last_page=max_pages)
                 
                 if not imgs:
                     continue
                     
-                return imgs[0].convert("RGB")
+                return [img.convert("RGB") for img in imgs]
             except Exception as e:
                 if poppler_path is None:  # All pdf2image attempts failed
                     break
@@ -139,20 +139,48 @@ def load_first_page(path: str, dpi: int = 300) -> Image.Image:
         if HAS_PYMUPDF:
             try:
                 doc = fitz.open(path)
-                page = doc[0]  # First page
-                mat = fitz.Matrix(dpi/72, dpi/72)  # Scale factor for DPI
-                pix = page.get_pixmap(matrix=mat)
-                img_data = pix.tobytes("ppm")
-                img = Image.open(io.BytesIO(img_data))
+                pages = []
+                for page_num in range(min(len(doc), max_pages)):
+                    page = doc[page_num]
+                    mat = fitz.Matrix(dpi/72, dpi/72)  # Scale factor for DPI
+                    pix = page.get_pixmap(matrix=mat)
+                    img_data = pix.tobytes("ppm")
+                    img = Image.open(io.BytesIO(img_data))
+                    pages.append(img.convert("RGB"))
                 doc.close()
-                return img.convert("RGB")
+                return pages
             except Exception as e:
                 raise ValueError(f"Failed to convert PDF with both pdf2image and PyMuPDF. pdf2image error: poppler not found. PyMuPDF error: {str(e)}")
         else:
             raise ValueError(f"Failed to convert PDF to image with all poppler paths. Last error: poppler not found. PyMuPDF not available as fallback.")
                 
         raise ValueError(f"No pages in PDF: {path}")
-    return Image.open(path).convert("RGB")
+    return [Image.open(path).convert("RGB")]
+
+def combine_pages_vertically(pages: List[Image.Image], spacing: int = 20) -> Image.Image:
+    """Combine multiple pages into a single vertical image"""
+    if not pages:
+        raise ValueError("No pages to combine")
+    if len(pages) == 1:
+        return pages[0]
+    
+    # Find the maximum width
+    max_width = max(page.width for page in pages)
+    
+    # Calculate total height
+    total_height = sum(page.height for page in pages) + spacing * (len(pages) - 1)
+    
+    # Create combined image
+    combined = Image.new('RGB', (max_width, total_height), (255, 255, 255))
+    
+    y_offset = 0
+    for page in pages:
+        # Center the page horizontally if it's narrower than max_width
+        x_offset = (max_width - page.width) // 2
+        combined.paste(page, (x_offset, y_offset))
+        y_offset += page.height + spacing
+    
+    return combined
 
 def match_sizes(a: Image.Image, b: Image.Image) -> Tuple[Image.Image, Image.Image]:
     if a.size == b.size:
@@ -455,9 +483,13 @@ def compare_pdfs(file_a, file_b):
         if file_a is None or file_b is None:
             return None, None, None, "❌ Please upload both PDF files to compare", [], []
 
-        # Load images with default settings
-        a = load_first_page(file_a.name, dpi=300)
-        b = load_first_page(file_b.name, dpi=300)
+        # Load images with multiple pages support
+        pages_a = load_pdf_pages(file_a.name, dpi=300, max_pages=5)
+        pages_b = load_pdf_pages(file_b.name, dpi=300, max_pages=5)
+        
+        # Combine pages into single images for comparison
+        a = combine_pages_vertically(pages_a)
+        b = combine_pages_vertically(pages_b)
 
         # Match sizes
         a, b = match_sizes(a, b)
@@ -495,10 +527,11 @@ def compare_pdfs(file_a, file_b):
         # Create status message
         status = f"""
         📊 **Analysis Complete!**
+        - **Pages processed:** A: {len(pages_a)}, B: {len(pages_b)}
         - **Difference regions found:** {len(red_boxes)}
         - **Misspellings detected:** A: {len(misspell_a)}, B: {len(misspell_b)}
         - **Barcodes found:** A: {len(bar_a)}, B: {len(bar_b)}
-        - **Image dimensions:** {a.width} × {a.height} pixels
+        - **Combined image dimensions:** {a.width} × {a.height} pixels
 
         **Legend:**
         - 🔴 Red boxes: Visual differences
@@ -525,6 +558,7 @@ def create_demo():
         # 🔍 Advanced PDF Comparison Tool
 
         Upload two PDF files to get comprehensive analysis including:
+        - **Multi-page PDF support** (up to 5 pages per document)
         - **Visual differences** with bounding boxes
         - **OCR and spell checking**
         - **Barcode/QR code detection**