message: immediately return if trim is not selected.
diff: @@ -525,6 +525,9 @@ See https://github.com/adobe-type-tools/cmap-resources
  const getTrimScale = () => {
  var trimSelect = document.getElementById("trimSelect");
  + if (trimSelect.selectedIndex <= 0) {
  + return 1.0;
  + }
  var trimValue = trimSelect.options[trimSelect.selectedIndex].value;
  return 1.0/(1 - 2*trimValue);
  };
  @@ -550,7 +553,7 @@ See https://github.com/adobe-type-tools/cmap-resources
  for ( o of scaleSelect.options ) {
  o.disabled = true;
  }
  - if (currentUserSelectScale == undefined) {
  + if (currentUserSelectScale === undefined) {
  currentUserSelectScale = PDFViewerApplication.pdfViewer._currentScale;
  }
  if (originalUserSelectIndex === undefined) {
  @@ -563,24 +566,27 @@ See https://github.com/adobe-type-tools/cmap-resources
  });
  window.addEventListener("pagerendered", (ev) => {
  + var trimSelect = document.getElementById("trimSelect");
  + if (trimSelect.selectedIndex <= 0) {
  + return;
  + }
  var trimScale = getTrimScale();
  var v = document.getElementById("viewer");
  for( var page of v.getElementsByClassName("page") ){
  var textLayer = page.getElementsByClassName("textLayer") ? page.getElementsByClassName("textLayer")[0] : undefined;
  var canvasWrapper = page.getElementsByClassName("canvasWrapper") ? page.getElementsByClassName("canvasWrapper")[0] : undefined;
  var canvas = page.getElementsByTagName("canvas") ? page.getElementsByTagName("canvas")[0] : undefined;
  - if ( canvasWrapper === undefined || canvas === undefined || canvas.isTrimmed ) {
  + if ( textLayer === undefined || canvasWrapper === undefined || canvas === undefined || canvas.isTrimmed ) {
  continue;
  }
  var w = page.style.width;
  var m;
  if (m = w.match(/(\d+)/)) {
  - page.style.width = Number(m[1])/trimScale + 'px';
  - canvasWrapper.style.width = Number(m[1])/trimScale + 'px';
  + var width = Number(m[1])/trimScale + 'px';
  + page.style.width = width;
  + canvasWrapper.style.width = width;
  var offsetX = '-' + Number(m[1]) * (1 - 1/trimScale) / 2 + "px";
  - if (textLayer !== undefined) {
  textLayer.style.left = offsetX;
  - }
  canvas.style.left = offsetX;
  canvas.style.position = "relative";
  canvas.isTrimmed = true;
  