/// <summary>
/// The mobile apps have an unchangeable black background, meaning dark text is unreadable there.
/// As a workaround, we overlap the dark subtitle with an invisible bright one: this way, we
/// get the custom background and dark text on PC, and a black background and bright text
/// on Android (because the Android app doesn't support transparency).
/// Sadly, this trick doesn't work for iOS: that one supports (only) text transparency,
/// meaning our bright yet invisible subtitle doesn't show up there.
/// </summary>
private int ExpandLineForDarkText(int lineIdx)
{
Line line = Lines[lineIdx];
if (!line.Sections.Any(s => s.ForeColor.A > 0 && ColorUtil.IsDark(s.ForeColor)))
{
return(1);
}
Line brightLine = (Line)line.Clone();
foreach (Section section in brightLine.Sections)
{
if (section.ForeColor.A > 0 && ColorUtil.IsDark(section.ForeColor))
{
section.ForeColor = ColorUtil.Brighten(section.ForeColor);
}
section.ForeColor = ColorUtil.ChangeColorAlpha(section.ForeColor, 0);
section.BackColor = ColorUtil.ChangeColorAlpha(section.BackColor, 0);
section.ShadowColors.Clear();
}
Lines.Insert(lineIdx + 1, brightLine);
return(2);
}