// set a transparent-background GrahpicsMode
QDRect moveFrom = new QDRect(0, 0, width, height);
QDRect moveTo = new QDRect(x, y, width, height);
Matrix matrix = new Matrix();
matrix.rect(moveFrom, moveTo);
tcTrack.setMatrix (matrix);
// if transparency is indicated, make the special value the transparent
// color
if (bgColor[0] == -1)