9278774b8a
- Replaced direct calls to PDFDocument.load with loadPdfDocument in multiple nodes to standardize PDF loading process.
97 lines
3.3 KiB
TypeScript
97 lines
3.3 KiB
TypeScript
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 { PDFDocument } from 'pdf-lib';
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import * as pdfjsLib from 'pdfjs-dist';
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import { loadPdfDocument } from '../../utils/load-pdf-document.js';
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export class RemoveBlankPagesNode extends BaseWorkflowNode {
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readonly category = 'Edit & Annotate' as const;
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readonly icon = 'ph-file-minus';
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readonly description = 'Remove blank pages automatically';
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constructor() {
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super('Remove Blank Pages');
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this.addInput('pdf', new ClassicPreset.Input(pdfSocket, 'PDF'));
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this.addOutput('pdf', new ClassicPreset.Output(pdfSocket, 'PDF'));
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this.addControl(
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'threshold',
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new ClassicPreset.InputControl('number', { initial: 250 })
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);
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}
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private async isPageBlank(
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page: pdfjsLib.PDFPageProxy,
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maxNonWhitePercent: number
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): Promise<boolean> {
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const viewport = page.getViewport({ scale: 0.5 });
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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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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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const data = imageData.data;
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const totalPixels = data.length / 4;
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let nonWhitePixels = 0;
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for (let i = 0; i < data.length; i += 4) {
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const brightness = (data[i] + data[i + 1] + data[i + 2]) / 3;
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if (brightness < 240) nonWhitePixels++;
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}
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const nonWhitePercent = (nonWhitePixels / totalPixels) * 100;
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return nonWhitePercent <= maxNonWhitePercent;
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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, 'Remove Blank Pages');
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const threshCtrl = this.controls['threshold'] as
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| ClassicPreset.InputControl<'number'>
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| undefined;
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const maxNonWhitePercent = Math.max(
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0.1,
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Math.min(5, threshCtrl?.value ?? 0.5)
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);
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return {
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pdf: await processBatch(pdfInputs, async (input) => {
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const pdfjsDoc = await pdfjsLib.getDocument({ data: input.bytes })
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.promise;
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const srcDoc = await loadPdfDocument(input.bytes);
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const nonBlankIndices: number[] = [];
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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 blank = await this.isPageBlank(page, maxNonWhitePercent);
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if (!blank) {
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nonBlankIndices.push(i - 1);
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} else {
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console.log(`Page ${i} detected as blank, removing`);
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}
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}
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if (nonBlankIndices.length === 0) {
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throw new Error('All pages are blank');
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}
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const newDoc = await PDFDocument.create();
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const copiedPages = await newDoc.copyPages(srcDoc, nonBlankIndices);
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copiedPages.forEach((page) => newDoc.addPage(page));
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const pdfBytes = await newDoc.save();
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return {
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type: 'pdf',
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document: newDoc,
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bytes: new Uint8Array(pdfBytes),
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filename: input.filename.replace(/\.pdf$/i, '_cleaned.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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