import fitz import math import io import uuid import base64 from flask import Flask, request, jsonify, render_template from PIL import Image from reportlab.pdfgen import canvas from reportlab.lib.pagesizes import A3, A4, A5, A6 from reportlab.lib.utils import ImageReader app = Flask(__name__) app.config['MAX_CONTENT_LENGTH'] = 200 * 1024 * 1024 # 200 MB PREVIEW_SCALE = 1.0 EXPORT_SCALE = 4.0 PAGE_SIZES = { 'A3': A3, 'A4': A4, 'A5': A5, 'A6': A6, 'Letter': (612, 792), 'Legal': (612, 1008), 'Custom': None, } def in_to_pt(i): return i * 72.0 def mm_to_pt(m): return m * 2.83465 def find_best_layout(ipp, img_w, img_h, page_w, page_h, margin, gap): usable_w = page_w - 2 * margin usable_h = page_h - 2 * margin best = None for cols in range(1, ipp + 1): rows = math.ceil(ipp / cols) cell_w = (usable_w - gap * (cols - 1)) / cols cell_h = (usable_h - gap * (rows - 1)) / rows scale = min(cell_w / img_w, cell_h / img_h) if scale <= 0: continue area = (img_w * scale) * (img_h * scale) if best is None or area > best['area']: best = {'cols': cols, 'rows': rows, 'label_w': img_w * scale, 'label_h': img_h * scale, 'area': area} return best @app.route('/') def index(): return render_template('index.html') @app.route('/api/upload', methods=['POST']) def upload_pdf(): """ Receive one PDF file. Extract page count and (optionally) a preview image. Return the PDF bytes as base64 to be stored in the browser. The server stores nothing — zero session state. """ if 'file' not in request.files: return jsonify({'error': 'No file uploaded'}), 400 f = request.files['file'] if not f.filename.lower().endswith('.pdf'): return jsonify({'error': 'File must be a PDF'}), 400 is_first = request.form.get('is_first', 'false').lower() == 'true' pdf_bytes = f.read() try: pdf = fitz.open(stream=pdf_bytes, filetype='pdf') page_count = len(pdf) preview_b64 = None if is_first: pix = pdf[0].get_pixmap(matrix=fitz.Matrix(PREVIEW_SCALE, PREVIEW_SCALE)) preview_b64 = base64.b64encode(pix.tobytes('png')).decode('utf-8') pdf.close() except Exception as e: return jsonify({'error': f'Could not read PDF: {e}'}), 400 # Send the PDF bytes back to the browser as base64 — browser owns the data pdf_b64 = base64.b64encode(pdf_bytes).decode('utf-8') resp = { 'file_id': str(uuid.uuid4()), 'name': f.filename, 'page_count': page_count, 'pdf_b64': pdf_b64, # browser stores this } if preview_b64: resp['preview'] = f'data:image/png;base64,{preview_b64}' resp['preview_w'] = pix.width resp['preview_h'] = pix.height return jsonify(resp) @app.route('/api/process', methods=['POST']) def process(): """ Fully stateless. The browser sends all PDF bytes (as base64 list) with the request. Server processes and returns the output PDF as base64. Nothing is stored anywhere. """ data = request.json or {} pdfs_b64 = data.get('pdfs', []) # [{ file_id, name, pdf_b64, page_count }, ...] crop = data.get('crop') ipp = int(data.get('items_per_page', 0)) margin_mm = float(data.get('margin_mm', 3)) gap_mm = float(data.get('gap_mm', 1)) page_size = data.get('page_size', 'A4') custom_w = data.get('custom_w_in') custom_h = data.get('custom_h_in') if not pdfs_b64: return jsonify({'error': 'No PDF data provided — please re-upload your files'}), 400 if not crop: return jsonify({'error': 'No crop region provided'}), 400 # Resolve page size if page_size == 'Custom': if not custom_w or not custom_h: return jsonify({'error': 'Custom size requires width and height in inches'}), 400 pw = in_to_pt(float(custom_w)) ph = in_to_pt(float(custom_h)) page_w, page_h = (pw, ph) if ph >= pw else (ph, pw) elif page_size in PAGE_SIZES: page_w, page_h = PAGE_SIZES[page_size] else: return jsonify({'error': f'Unknown page size: {page_size}'}), 400 sf = EXPORT_SCALE / PREVIEW_SCALE rx1, ry1 = int(crop['x1'] * sf), int(crop['y1'] * sf) rx2, ry2 = int(crop['x2'] * sf), int(crop['y2'] * sf) if rx2 <= rx1 or ry2 <= ry1: return jsonify({'error': 'Invalid crop region — please redraw the selection'}), 400 # Decode and crop every page of every PDF cropped_images = [] export_mat = fitz.Matrix(EXPORT_SCALE, EXPORT_SCALE) try: for entry in pdfs_b64: pdf_bytes = base64.b64decode(entry['pdf_b64']) pdf = fitz.open(stream=pdf_bytes, filetype='pdf') for page_num in range(len(pdf)): pix = pdf[page_num].get_pixmap(matrix=export_mat, alpha=False) image = Image.open(io.BytesIO(pix.tobytes('png'))) cropped_images.append(image.crop((rx1, ry1, rx2, ry2))) pdf.close() except Exception as e: return jsonify({'error': f'PDF processing error: {e}'}), 500 total = len(cropped_images) if total == 0: return jsonify({'error': 'No pages found in uploaded files'}), 400 img_w, img_h = cropped_images[0].size if img_w == 0 or img_h == 0: return jsonify({'error': 'Crop region is empty — please redraw the selection'}), 400 if ipp == 0: ipp = total margin = mm_to_pt(margin_mm) gap = mm_to_pt(gap_mm) layout = find_best_layout(ipp, img_w, img_h, page_w, page_h, margin, gap) if not layout: return jsonify({'error': 'Labels do not fit — try reducing margins/gap or a larger page size'}), 400 cols, rows = layout['cols'], layout['rows'] label_w, label_h = layout['label_w'], layout['label_h'] cell_w = (page_w - 2 * margin - gap * (cols - 1)) / cols cell_h = (page_h - 2 * margin - gap * (rows - 1)) / rows try: buf = io.BytesIO() pdf_canvas = canvas.Canvas(buf, pagesize=(page_w, page_h)) idx = 0 while idx < total: for i, image in enumerate(cropped_images[idx:idx + ipp]): row, col = divmod(i, cols) x = margin + col * (cell_w + gap) y = page_h - margin - (row + 1) * cell_h - row * gap draw_x = x + (cell_w - label_w) / 2 draw_y = y + (cell_h - label_h) / 2 pdf_canvas.drawImage(ImageReader(image), draw_x, draw_y, width=label_w, height=label_h) idx += ipp if idx < total: pdf_canvas.showPage() pdf_canvas.save() buf.seek(0) out_b64 = base64.b64encode(buf.read()).decode('utf-8') except Exception as e: return jsonify({'error': f'PDF generation error: {e}'}), 500 return jsonify({ 'pdf_b64': out_b64, 'filename': f'shipsheet_{page_size.lower()}.pdf', 'total_labels': total, 'items_per_page': ipp, 'cols': cols, 'rows': rows, 'output_pages': math.ceil(total / ipp), 'page_size': page_size, }) if __name__ == '__main__': app.run(debug=False)