src/lib/utils/exportPdf.ts - main - ncit/c4panelmodel

src/lib/utils/exportPdf.ts
92 строки2 KB
ncit
feat: implement full IcePanel feature clone (Phases 1-8)
09 июн 2026, 11:13
09 июн 2026, 11:13858c15a
/**
 * Export diagram as PDF using jsPDF (browser-side).
 * Wraps PNG export into a PDF page.
 */

import { exportPng } from './exportImage';

export interface PdfOptions {
	theme?: 'light' | 'dark';
	pageSize?: 'a4' | 'letter' | 'fit';
	orientation?: 'portrait' | 'landscape';
	scale?: number;
}

export async function exportPdf(element: HTMLElement, opts: PdfOptions = {}): Promise<Blob> {
	const { jsPDF } = await import('jspdf');

	// Determine page dimensions in mm.
	const pageSizes: Record<string, [number, number]> = {
		a4: [210, 297],
		letter: [215.9, 279.4],
		fit: [0, 0] // will be computed from image aspect ratio
	};

	const [pw, ph] = pageSizes[opts.pageSize ?? 'a4'] ?? pageSizes.a4;
	const orientation = opts.orientation ?? 'landscape';
	const width = orientation === 'landscape' ? Math.max(pw, ph) : Math.min(pw, ph);
	const height = orientation === 'landscape' ? Math.min(pw, ph) : Math.max(pw, ph);

	// Render element to PNG.
	const pngBlob = await exportPng(element, { theme: opts.theme, scale: opts.scale });
	const pngUrl = URL.createObjectURL(pngBlob);

	try {
		const doc = new jsPDF({
			orientation,
			unit: 'mm',
			format: opts.pageSize === 'fit' ? undefined : [width, height]
		});

		// For 'fit' mode, compute dimensions from image aspect ratio.
		const img = await loadImage(pngUrl);
		let imgW: number;
		let imgH: number;

		if (opts.pageSize === 'fit') {
			const aspect = img.width / img.height;
			// Use A4 width as base, compute height from aspect.
			imgW = width;
			imgH = width / aspect;
			// Recreate doc with computed size.
			const fitDoc = new jsPDF({
				orientation,
				unit: 'mm',
				format: [imgW, imgH]
			});
			fitDoc.addImage(pngUrl, 'PNG', 0, 0, imgW, imgH);
			return fitDoc.output('blob');
		} else {
			// Fit image within page with margins.
			const margin = 10;
			const maxW = width - margin * 2;
			const maxH = height - margin * 2;
			const aspect = img.width / img.height;

			if (maxW / aspect <= maxH) {
				imgW = maxW;
				imgH = maxW / aspect;
			} else {
				imgH = maxH;
				imgW = maxH * aspect;
			}

			const x = (width - imgW) / 2;
			const y = (height - imgH) / 2;

			doc.addImage(pngUrl, 'PNG', x, y, imgW, imgH);
			return doc.output('blob');
		}
	} finally {
		URL.revokeObjectURL(pngUrl);
	}
}

function loadImage(src: string): Promise<HTMLImageElement> {
	return new Promise((resolve, reject) => {
		const img = new Image();
		img.onload = () => resolve(img);
		img.onerror = reject;
		img.src = src;
	});
}