message: Signature Pad has black background for dataFormat JPEG
diff: @@ -72,7 +72,7 @@ export class QuestionSignaturePadModel extends Question {
  initSignaturePad(el: HTMLElement) {
  var canvas: any = el.getElementsByTagName("canvas")[0];
  var buttonEl = el.getElementsByTagName("button")[0];
  - var signaturePad = new SignaturePad(canvas);
  + var signaturePad = new SignaturePad(canvas, { backgroundColor: "#ffffff" });
  if (this.isReadOnly) {
  signaturePad.off();
  }
  @@ -188,24 +188,29 @@ export class QuestionSignaturePadModel extends Question {
  Serializer.addClass(
  "signaturepad",
  [
  - {
  - name: "allowClear:boolean",
  - default: true,
  - },
  {
  name: "width:number",
  + category: "general",
  default: 300,
  },
  {
  name: "height:number",
  + category: "general",
  default: 200,
  },
  {
  - name: "penColor",
  + name: "allowClear:boolean",
  + category: "general",
  + default: true,
  + },
  + {
  + name: "penColor:color",
  + category: "general",
  default: "#1ab394",
  },
  {
  name: "dataFormat",
  + category: "general",
  default: "",
  choices: [
  { value: "", text: "PNG" },
  @@ -213,6 +218,8 @@ Serializer.addClass(
  { value: "image/svg+xml", text: "SVG" },
  ],
  },
  + { name: "defaultValue", visible: false },
  + { name: "correctAnswer", visible: false },
  ],
  function () {
  return new QuestionSignaturePadModel("");
  