Put a mark corresponding to the specified dataset at the specified x and y position. The mark is drawn in the current color. In this base class, a point is a filled rectangle 6 pixels across. Note that marks greater than about 6 pixels in size will not look very good since they will overlap axis labels and may not fit well in the legend. The clip argument, if
Note that this method is not synchronized, so the caller should be. Moreover this method should always be called from the event thread when being used to write to the screen.
Reimplemented in ptolemy::plot::Plot.