Add visual workflow builder, fix critical bugs, and add Arabic i18n support

src/js/workflow/nodes/greyscale-node.ts

@@ -0,0 +1,76 @@
+import { ClassicPreset } from 'rete';
+import { BaseWorkflowNode } from './base-node';
+import { pdfSocket } from '../sockets';
+import type { SocketData } from '../types';
+import { requirePdfInput, processBatch } from '../types';
+import { applyGreyscale } from '../../utils/image-effects';
+import { PDFDocument } from 'pdf-lib';
+import * as pdfjsLib from 'pdfjs-dist';
+
+export class GreyscaleNode extends BaseWorkflowNode {
+  readonly category = 'Edit & Annotate' as const;
+  readonly icon = 'ph-palette';
+  readonly description = 'Convert to greyscale';
+
+  constructor() {
+    super('Greyscale');
+    this.addInput('pdf', new ClassicPreset.Input(pdfSocket, 'PDF'));
+    this.addOutput('pdf', new ClassicPreset.Output(pdfSocket, 'Greyscale PDF'));
+  }
+
+  async data(
+    inputs: Record<string, SocketData[]>
+  ): Promise<Record<string, SocketData>> {
+    const pdfInputs = requirePdfInput(inputs, 'Greyscale');
+
+    return {
+      pdf: await processBatch(pdfInputs, async (input) => {
+        const newPdfDoc = await PDFDocument.create();
+        const pdfjsDoc = await pdfjsLib.getDocument({ data: input.bytes })
+          .promise;
+
+        for (let i = 1; i <= pdfjsDoc.numPages; i++) {
+          const page = await pdfjsDoc.getPage(i);
+          const viewport = page.getViewport({ scale: 2.0 });
+
+          const canvas = document.createElement('canvas');
+          canvas.width = viewport.width;
+          canvas.height = viewport.height;
+          const ctx = canvas.getContext('2d');
+          if (!ctx)
+            throw new Error(`Failed to get canvas context for page ${i}`);
+          await page.render({ canvasContext: ctx, viewport, canvas }).promise;
+
+          const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
+          applyGreyscale(imageData);
+          ctx.putImageData(imageData, 0, 0);
+
+          const jpegBlob = await new Promise<Blob | null>((resolve) =>
+            canvas.toBlob(resolve, 'image/jpeg', 0.9)
+          );
+
+          if (!jpegBlob) throw new Error(`Failed to render page ${i} to image`);
+          const jpegBytes = await jpegBlob.arrayBuffer();
+          const jpegImage = await newPdfDoc.embedJpg(jpegBytes);
+          const newPage = newPdfDoc.addPage([viewport.width, viewport.height]);
+          newPage.drawImage(jpegImage, {
+            x: 0,
+            y: 0,
+            width: viewport.width,
+            height: viewport.height,
+          });
+        }
+
+        if (newPdfDoc.getPageCount() === 0)
+          throw new Error('No pages were processed');
+        const pdfBytes = await newPdfDoc.save();
+        return {
+          type: 'pdf',
+          document: newPdfDoc,
+          bytes: new Uint8Array(pdfBytes),
+          filename: input.filename.replace(/\.pdf$/i, '_greyscale.pdf'),
+        };
+      }),
+    };
+  }
+}