Add a missing prepareColor function call in text background color (#303)

Author: patrick-tolosa

__TESTS__/unit/actions/Overlay.test.ts

@@ -10,6 +10,7 @@ import {Format, png} from "../../../src/values/format";
 import {Underlay} from "../../../src/actions/underlay";
 import {Timeline} from "../../../src/values/timeline";
 import {base64Encode} from "../../../src/internal/utils/base64Encode";
+import {TextStyle} from "../../../src/values/textStyle";
 
 describe('Tests for overlay actions', () => {
   it('Tests Image on Image with publicID encoding', () => {
@@ -82,6 +83,18 @@ describe('Tests for overlay actions', () => {
     expect(asset.toString()).toBe(`b_red,co_blue,l_text:${textStyle.toString()}:Testing/fl_layer_apply`);
   });
 
+  it('Tests text on image with RGB backgroundColor', () => {
+    const asset = createNewImage();
+
+    asset.overlay(Overlay.source(
+      Source.text('Testing', new TextStyle('arial', 15))
+        .backgroundColor('#FEB61FC2')
+        .textColor('blue')
+    ));
+
+    expect(asset.toString()).toBe(`b_rgb:FEB61FC2,co_blue,l_text:arial_15:Testing/fl_layer_apply`);
+  });
+
   it('Tests nested subtitles on image', () => {
     const asset = createNewImage();
     const textStyle = sampleTextStyle();

src/values/source/sourceTypes/BaseTextSource.ts

@@ -56,7 +56,7 @@ class BaseTextSource extends BaseSource {
 
     tmpAction.addQualifier(new Qualifier(layerType, layerParam));
     this._textColor && tmpAction.addQualifier(new Qualifier('co', prepareColor(this._textColor)));
-    this._backgroundColor && tmpAction.addQualifier(new Qualifier('b', this._backgroundColor));
+    this._backgroundColor && tmpAction.addQualifier(new Qualifier('b', prepareColor(this._backgroundColor)));
 
     return tmpAction.toString();
   }