pdf.js Fixed Width

 const url = 'my.pdf';
  pdfjsLib.GlobalWorkerOptions.workerSrc = 'https://cdn.jsdelivr.net/npm/[email protected]/build/pdf.worker.min.js';
  const loadingTask = pdfjsLib.getDocument(url);
  (async () => {
    const pdf = await loadingTask.promise;
    const page = await pdf.getPage(1);
    const outputScale = window.devicePixelRatio || 1;
    const canvas = document.getElementById("the-canvas");
    const context = canvas.getContext("2d");
    var desiredWidth = 380;
    var viewport = page.getViewport({ scale: 1, });
    var scale = desiredWidth / viewport.width;
    var scaledViewport = page.getViewport({ scale: scale, });
    canvas.width = Math.floor(viewport.width * scale);
    canvas.height = Math.floor(viewport.height * scale);
    const renderContext = {
      canvasContext: context,
      viewport,
    };
    page.render(renderContext);
  })();