Label background color

[Keith, T. <ke...@um...>]

I'm using qt-win-commercial-src-4.0.1-snapshot-20050721.zip and the =
latest qwtplot3d-0.2.5

In Label::update(), I found it necessary to do the following to avoid a =
white label background (which is undesirable if plot background color is =
not white)

pm_.setMask(bm);

GLdouble col[4];

glGetDoublev(GL_COLOR_CLEAR_VALUE, col);

pm_.fill(GL2Qt(col[0], col[1], col[2]));