feat: implement backend label print agent system for remote label rendering and job management

2026-05-07 22:46:29 +02:00
parent 0c94e7b999
commit 80f862a0c0
15 changed files with 995 additions and 15 deletions
@@ -0,0 +1,81 @@
+import { Injectable, Logger } from '@nestjs/common';
+import * as QRCode from 'qrcode';
+import sharp from 'sharp';
+import type { LabelElement } from '../database/entities/barcode-template.entity';
+
+const MM_TO_PX = 300 / 25.4; // 300 DPI
+
+function mm(v: number): number {
+  return Math.round(v * MM_TO_PX);
+}
+
+function escape(s: string): string {
+  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+
+function applyVars(template: string, vars: Record<string, string>): string {
+  return template.replace(/\{([^}]+)\}/g, (_, key) => vars[key] ?? `{${key}}`);
+}
+
+@Injectable()
+export class LabelRendererService {
+  private readonly logger = new Logger(LabelRendererService.name);
+
+  async render(
+    layout: LabelElement[],
+    widthMm: number,
+    heightMm: number,
+    variables: Record<string, string>,
+  ): Promise<Buffer> {
+    const W = mm(widthMm);
+    const H = mm(heightMm);
+
+    const parts: string[] = [];
+
+    for (const el of layout) {
+      if (el.type === 'text') {
+        const x = mm(el.x);
+        const y = mm(el.y);
+        const fontSize = mm(el.fontSize);
+        const content = escape(applyVars(el.content, variables));
+        const fontWeight = el.bold ? 'bold' : 'normal';
+        const textAnchor = el.align === 'center' ? 'middle' : el.align === 'right' ? 'end' : 'start';
+        const maxWidthAttr = el.maxWidth ? ` textLength="${mm(el.maxWidth)}" lengthAdjust="spacingAndGlyphs"` : '';
+        parts.push(
+          `<text x="${x}" y="${y}" font-family="Arial,Helvetica,sans-serif" font-size="${fontSize}" font-weight="${fontWeight}" text-anchor="${textAnchor}" dominant-baseline="hanging"${maxWidthAttr}>${content}</text>`,
+        );
+      } else if (el.type === 'qr') {
+        const x = mm(el.x);
+        const y = mm(el.y);
+        const size = mm(el.sizeMm);
+        const content = applyVars(el.content, variables);
+        try {
+          const qrBuffer = await QRCode.toBuffer(content, {
+            type: 'png',
+            margin: 0,
+            width: size,
+            errorCorrectionLevel: 'M',
+          });
+          const b64 = qrBuffer.toString('base64');
+          parts.push(`<image href="data:image/png;base64,${b64}" x="${x}" y="${y}" width="${size}" height="${size}"/>`);
+        } catch (err: any) {
+          this.logger.warn(`QR-Code-Rendering fehlgeschlagen für "${content}": ${err.message}`);
+        }
+      } else if (el.type === 'line') {
+        const x1 = mm(el.x1);
+        const y1 = mm(el.y1);
+        const x2 = mm(el.x2);
+        const y2 = mm(el.y2);
+        const strokeWidth = el.lineWidth ? mm(el.lineWidth) : 1;
+        parts.push(`<line x1="${x1}" y1="${y1}" x2="${x2}" y2="${y2}" stroke="black" stroke-width="${strokeWidth}"/>`);
+      }
+    }
+
+    const svg = `<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="${W}" height="${H}" viewBox="0 0 ${W} ${H}">
+  <rect width="${W}" height="${H}" fill="white"/>
+  ${parts.join('\n  ')}
+</svg>`;
+
+    return sharp(Buffer.from(svg)).png().toBuffer();
+  }
+}