92 lines
3.3 KiB
TypeScript
92 lines
3.3 KiB
TypeScript
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import Joi from "@stirling-tools/joi";
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import { PDFPage } from "pdf-lib";
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import { PdfFile, RepresentationType } from "../wrappers/PdfFile";
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import { JoiPDFFileSchema } from "../wrappers/PdfFileJoi";
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const whSchema = Joi.string().custom((value, helpers) => {
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console.log("value.pageSize", typeof value);
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try {
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const obj = JSON.parse(value);
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if (!obj.width && !obj.height) {
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return helpers.error("any.required", { message: "At least one of width/height must be present" });
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}
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if (typeof obj.width != "number" && typeof obj.width != "undefined") {
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return helpers.error("any.invalid", { message: "Width must be a number if present" });
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}
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if (typeof obj.height != "number" && typeof obj.height != "undefined") {
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return helpers.error("any.invalid", { message: "Height must be a number if present" });
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}
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return obj;
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} catch (error) {
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return helpers.error("any.invalid", { message: "Value must be a valid JSON" });
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}
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});
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export const ScalePageSchema = Joi.object({
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file: JoiPDFFileSchema.required(),
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pageSize: Joi.alternatives().try(whSchema, Joi.array().items(whSchema)).required(),
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});
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export interface ScalePageParamsType {
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file: PdfFile;
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pageSize: { width?:number,height?:number }|{ width?:number,height?:number }[];
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}
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export async function scalePage(params: ScalePageParamsType): Promise<PdfFile> {
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const { file, pageSize } = params;
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const pdfDoc = await file.pdfLibDocument;
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const pages = pdfDoc.getPages();
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if (Array.isArray(pageSize)) {
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if (pageSize.length != pages.length) {
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throw new Error(`Number of given sizes '${pageSize.length}' is not the same as the number of pages '${pages.length}'`);
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}
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for (let i=0; i<pageSize.length; i++) {
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resize(pages[i], pageSize[i]);
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}
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} else {
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pages.forEach(page => { resize(page, pageSize) });
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}
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return new PdfFile(file.originalFilename, pdfDoc, RepresentationType.PDFLibDocument, file.filename+"_scaledPages");
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}
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function resize(page: PDFPage, newSize: {width?:number,height?:number}) {
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const calculatedSize = calculateSize(page, newSize);
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const xRatio = calculatedSize.width / page.getWidth();
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const yRatio = calculatedSize.height / page.getHeight();
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page.setSize(calculatedSize.width, calculatedSize.height);
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page.scaleContent(xRatio, yRatio);
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}
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function calculateSize(page: PDFPage, newSize: {width?:number,height?:number}): {width:number,height:number} {
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if (!newSize.width && !newSize.height){
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throw new Error(`Sizes '${newSize}' cannot have null width and null height`);
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} else if (!newSize.width && newSize.height) {
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const oldSize = page.getSize();
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const ratio = oldSize.width / oldSize.height;
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return { width: newSize.height * ratio, height: newSize.height };
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} else if (newSize.width && !newSize.height) {
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const oldSize = page.getSize();
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const ratio = oldSize.height / oldSize.width;
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return { width: newSize.width, height: newSize.width * ratio };
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}
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return { width: newSize.width, height: newSize.height };
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}
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export const PageSize = Object.freeze({
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a4: {
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width: 594.96,
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height: 841.92
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},
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letter: {
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width: 612,
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height: 792
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}
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});
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