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