feat(image): add progressive JPEG generation support

- Add convertPDFToJpegBytes method for progressive JPEG images
- Integrate @push.rocks/smartjimp for true progressive encoding
- Update readme with comprehensive documentation
- Update legal section to Task Venture Capital GmbH

ts/smartpdf.classes.smartpdf.ts

@@ -538,4 +538,52 @@ export class SmartPdf {
     await page.close();
     return webpBuffers;
   }
+
+  /**
+   * Converts a PDF to progressive JPEG bytes for each page.
+   * This method creates progressive JPEG images that load in multiple passes,
+   * showing a low-quality preview first, then progressively improving.
+   * Uses SmartJimp for true progressive JPEG encoding.
+   */
+  public async convertPDFToJpegBytes(
+    pdfBytes: Uint8Array,
+    options: {
+      scale?: number;      // Scale factor for output size (default: 3.0 for 216 DPI)
+      quality?: number;    // JPEG quality 0-100 (default: 85)
+      maxWidth?: number;   // Maximum width in pixels (optional)
+      maxHeight?: number;  // Maximum height in pixels (optional)
+    } = {}
+  ): Promise<Uint8Array[]> {
+    // First, convert PDF to PNG using our existing method
+    const pngBuffers = await this.convertPDFToPngBytes(pdfBytes, {
+      scale: options.scale,
+      maxWidth: options.maxWidth,
+      maxHeight: options.maxHeight
+    });
+
+    // Initialize SmartJimp in sharp mode for progressive JPEG support
+    const smartJimpInstance = new plugins.smartjimp.SmartJimp({ mode: 'sharp' });
+    
+    // Convert each PNG to progressive JPEG
+    const jpegBuffers: Uint8Array[] = [];
+    const quality = options.quality || 85;
+    
+    for (const pngBuffer of pngBuffers) {
+      // Convert PNG buffer to progressive JPEG
+      const jpegBuffer = await smartJimpInstance.computeAssetVariation(
+        Buffer.from(pngBuffer),
+        {
+          format: 'jpeg',
+          progressive: true,
+          // SmartJimp uses a different quality scale, need to check if adjustment is needed
+          // For now, pass through the quality value
+          quality
+        }
+      );
+      
+      jpegBuffers.push(new Uint8Array(jpegBuffer));
+    }
+    
+    return jpegBuffers;
+  }
 }

ts/smartpdf.plugins.ts

@@ -13,6 +13,7 @@ import * as smartpath from '@push.rocks/smartpath';
 import * as smartpuppeteer from '@push.rocks/smartpuppeteer';
 import * as smartnetwork from '@push.rocks/smartnetwork';
 import * as smartunique from '@push.rocks/smartunique';
+import * as smartjimp from '@push.rocks/smartjimp';
 
 export {
   smartbuffer,
@@ -23,6 +24,7 @@ export {
   smartpuppeteer,
   smartunique,
   smartnetwork,
+  smartjimp,
 };
 
 // tsclass scope