PDF changes

- Scale pdf by 2, in order to read smaller QR Codes
- Read last page of PDF (2nd dose often on 2nd page)

src/process.js

@@ -1,49 +1,63 @@
-const PDFJS = require('pdfjs-dist')
-PDFJS.GlobalWorkerOptions.workerSrc = `https://cdnjs.cloudflare.com/ajax/libs/pdf.js/${PDFJS.version}/pdf.worker.js`
-
 import jpeg from 'jpeg-js'
-import { PNG } from 'pngjs'
+import {PNG} from 'pngjs'
+import * as PdfJS from 'pdfjs-dist'
 
+PdfJS.GlobalWorkerOptions.workerSrc = `https://cdnjs.cloudflare.com/ajax/libs/pdf.js/${PdfJS.version}/pdf.worker.js`
+
+// Processes a pdf file and returns it as ImageData
 export async function processPdf(file) {
-  var typedarray = new Uint8Array(file)
+    // Array to store ImageData information
+    const typedArray = new Uint8Array(file)
 
-  const canvas = document.getElementById('canvas')
-  const ctx = canvas.getContext('2d')
+    // PDF scale, increase to read smaller QR Codes
+    const pdfScale = 2;
 
-  var loadingTask = PDFJS.getDocument(typedarray)
-  await loadingTask.promise.then(async function (pdfDocument) {
-    const pdfPage = await pdfDocument.getPage(1)
-    const viewport = pdfPage.getViewport({ scale: 1 })
-    canvas.width = viewport.width
-    canvas.height = viewport.height
+    // Get the canvas and context to render PDF
+    const canvas = document.getElementById('canvas')
+    const ctx = canvas.getContext('2d')
 
-    const renderTask = pdfPage.render({
-      canvasContext: ctx,
-      viewport,
+    let loadingTask = PdfJS.getDocument(typedArray)
+
+    await loadingTask.promise.then(async function (pdfDocument) {
+        // Load last PDF page
+        const pageNumber = pdfDocument.numPages;
+
+        const pdfPage = await pdfDocument.getPage(pageNumber)
+        const viewport = pdfPage.getViewport({scale: pdfScale})
+
+        // Set correct canvas width / height
+        canvas.width = viewport.width
+        canvas.height = viewport.height
+
+        // render PDF
+        const renderTask = pdfPage.render({
+            canvasContext: ctx,
+            viewport,
+        })
+
+        return await renderTask.promise
     })
-    
-    return await renderTask.promise
-  })
 
-  var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height)
-
-  return imageData
+    // Return PDF Image Data
+    return ctx.getImageData(0, 0, canvas.width, canvas.height)
 }
 
+// Processes a JPEG File and returns it as ImageData
 export async function processJpeg(file) {
-  return jpeg.decode(file)
+    return jpeg.decode(file)
 }
 
+// Processes a PNG File and returns it as ImageData
 export async function processPng(file) {
-  return new Promise(async (resolve, reject) => {
-    let png = new PNG({ filterType: 4 })
-    
-    png.parse(file, (error, data) => {
-      if(error) {
-        reject()
-      }
+    return new Promise(async (resolve, reject) => {
+        let png = new PNG({filterType: 4})
 
-      resolve(data)
+        png.parse(file, (error, data) => {
+            if (error) {
+                reject()
+            }
+
+            resolve(data)
+        })
     })
-  })
 }