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010aafb6f4
Main module evaluation drops from ~420 ms to ~330 ms. Types stay as import type; the DeepSeek Harness chunks stay static because the protocol chunk shares code with Main startup paths.
61 lines
2.8 KiB
TypeScript
61 lines
2.8 KiB
TypeScript
// @napi-rs/canvas is a native module (~85 ms to load); load it on first OCR render (P6).
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export async function* renderOcrPdf(
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buffer: Buffer,
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pageNumbers: number[],
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signal?: AbortSignal
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): AsyncGenerator<{ pageNumber: number; data: Buffer; width: number; height: number }> {
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signal?.throwIfAborted()
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const [{ getDocument }, { createCanvas }] = await Promise.all([
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import('pdfjs-dist/legacy/build/pdf.mjs'),
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import('@napi-rs/canvas')
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])
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const task = getDocument({
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data: Uint8Array.from(buffer), disableFontFace: true,
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isOffscreenCanvasSupported: false, useSystemFonts: false, useWorkerFetch: false
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})
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const abort = (): void => { void task.destroy() }
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signal?.addEventListener('abort', abort, { once: true })
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try {
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const pdf = await task.promise
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for (const pageNumber of pageNumbers) {
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signal?.throwIfAborted()
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const page = await pdf.getPage(pageNumber)
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try {
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const original = page.getViewport({ scale: 1 })
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const viewport = page.getViewport({ scale: Math.min(2, 2400 / Math.max(original.width, original.height)) })
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const canvas = createCanvas(Math.ceil(viewport.width), Math.ceil(viewport.height))
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const render = page.render({ canvas: canvas as unknown as Parameters<typeof page.render>[0]['canvas'], viewport })
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const cancel = (): void => render.cancel()
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signal?.addEventListener('abort', cancel, { once: true })
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try { await render.promise } finally { signal?.removeEventListener('abort', cancel) }
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signal?.throwIfAborted()
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yield { pageNumber, data: await canvas.encode('png'), width: canvas.width, height: canvas.height }
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} finally { page.cleanup() }
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}
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} finally {
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signal?.removeEventListener('abort', abort)
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await task.destroy()
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}
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}
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export async function renderSelectedOcrPdf(buffer: Buffer, pageNumbers: number[], signal?: AbortSignal): Promise<Buffer> {
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const { jsPDF } = await import('jspdf')
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let document: InstanceType<typeof jsPDF> | undefined
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let bytes = 0
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for await (const page of renderOcrPdf(buffer, pageNumbers, signal)) {
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bytes += page.data.length
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if (bytes > 20 * 1024 * 1024) throw new Error('选中页面渲染结果超过 20 MiB，请减少单次解析页数')
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const format = [page.width / 2, page.height / 2]
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const orientation = page.width > page.height ? 'landscape' : 'portrait'
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if (!document) document = new jsPDF({ unit: 'pt', format, orientation, compress: true })
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else document.addPage(format, orientation)
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document.addImage(page.data, 'PNG', 0, 0, format[0]!, format[1]!, undefined, 'FAST')
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}
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signal?.throwIfAborted()
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if (!document) throw new Error('没有需要 OCR 的页面')
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const result = Buffer.from(document.output('arraybuffer'))
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if (result.length > 20 * 1024 * 1024) throw new Error('选中页面 PDF 超过 20 MiB')
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return result
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}
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