Add OCR, Background Removal, and PDF Editor features with tests

- Implemented OCR functionality using pytesseract for image and PDF text extraction.
- Added Background Removal service using rembg for image processing.
- Developed PDF Editor service for applying text annotations to PDF files.
- Created corresponding API routes for OCR, Background Removal, and PDF Editor.
- Added frontend components for OCR and Background Removal tools.
- Integrated feature flagging for new tools, ensuring they are disabled by default.
- Implemented comprehensive unit tests for OCR service, PDF editor, and background removal.
- Updated documentation to reflect new features and usage instructions.
- Added translations for new features in English, Arabic, and French.

backend/app/services/pdf_editor_service.py

@@ -0,0 +1,120 @@
+"""PDF Editor service — add text annotations and simple edits to PDFs."""
+import io
+import logging
+import os
+
+logger = logging.getLogger(__name__)
+
+
+class PDFEditorError(Exception):
+    """Custom exception for PDF editor failures."""
+    pass
+
+
+def apply_pdf_edits(input_path: str, output_path: str, edits: list[dict]) -> dict:
+    """Apply a list of edits (text annotations) to an existing PDF.
+
+    Each edit dict can contain:
+        - type: "text"
+        - page: 1-based page number
+        - x, y: position in points from bottom-left
+        - content: text string to place
+        - fontSize: optional, default 12
+        - color: optional hex e.g. "#000000"
+
+    Args:
+        input_path: Path to the source PDF.
+        output_path: Path for the edited PDF.
+        edits: List of edit operation dicts.
+
+    Returns:
+        dict with ``page_count``, ``edits_applied``, ``output_size``.
+
+    Raises:
+        PDFEditorError: If the edit fails.
+    """
+    if not edits:
+        raise PDFEditorError("No edits provided.")
+
+    os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+    try:
+        from PyPDF2 import PdfReader, PdfWriter
+        from reportlab.pdfgen import canvas
+        from reportlab.lib.pagesizes import letter
+        from reportlab.lib.colors import HexColor
+
+        reader = PdfReader(input_path)
+        writer = PdfWriter()
+        page_count = len(reader.pages)
+
+        if page_count == 0:
+            raise PDFEditorError("PDF has no pages.")
+
+        # Group edits by page
+        edits_by_page: dict[int, list[dict]] = {}
+        for edit in edits:
+            page_num = int(edit.get("page", 1))
+            if page_num < 1 or page_num > page_count:
+                continue
+            edits_by_page.setdefault(page_num, []).append(edit)
+
+        edits_applied = 0
+
+        for page_idx in range(page_count):
+            page = reader.pages[page_idx]
+            page_num = page_idx + 1
+            page_edits = edits_by_page.get(page_num, [])
+
+            if page_edits:
+                # Get page dimensions
+                media_box = page.mediabox
+                page_width = float(media_box.width)
+                page_height = float(media_box.height)
+
+                # Create overlay with annotations
+                packet = io.BytesIO()
+                c = canvas.Canvas(packet, pagesize=(page_width, page_height))
+
+                for edit in page_edits:
+                    edit_type = edit.get("type", "text")
+                    if edit_type == "text":
+                        x = float(edit.get("x", 72))
+                        y = float(edit.get("y", 72))
+                        content = str(edit.get("content", ""))
+                        font_size = int(edit.get("fontSize", 12))
+                        color = str(edit.get("color", "#000000"))
+
+                        try:
+                            c.setFillColor(HexColor(color))
+                        except Exception:
+                            c.setFillColor(HexColor("#000000"))
+
+                        c.setFont("Helvetica", font_size)
+                        c.drawString(x, y, content)
+                        edits_applied += 1
+
+                c.save()
+                packet.seek(0)
+
+                overlay_reader = PdfReader(packet)
+                if len(overlay_reader.pages) > 0:
+                    page.merge_page(overlay_reader.pages[0])
+
+            writer.add_page(page)
+
+        with open(output_path, "wb") as f:
+            writer.write(f)
+
+        output_size = os.path.getsize(output_path)
+
+        return {
+            "page_count": page_count,
+            "edits_applied": edits_applied,
+            "output_size": output_size,
+        }
+
+    except PDFEditorError:
+        raise
+    except Exception as e:
+        raise PDFEditorError(f"PDF editing failed: {str(e)}")