visibility of objects with hidden handles

[Ben Abbott]

The code below produces two sets of x/y-labels

        set (0, "showhiddenhandles", "on")
        clf
        plot ((0:2)-1, (0:2)-1)
        xlabel ("xlabel")
        ylabel ("ylabel")

This results in the labels being rendered twice. One as gnuplot axis  
labels

        set xlabel {"<label>"} {offset <offset>} ...

And once as text labels

        set label {<tag>} {"<label text>"} {at <position>} ...

The fix is to treat the axis labels and title specially. Once the  
placement of the axis labels is controlled by Octave, they will not  
need to be treated specially.

The double rendering was not readily apparent, because octave did not  
render objects with hidden handles. This is wrong as well. For  
example, the statement below should produce a visible result.

        ht = text (0, 0, "text with hidden handle", "handlevisibility", "off");

To suppress the visibility

        set (ht, "visible", "off")

A trivial changeset has been pushed to savannah, and is also attached.

Ben

changeset-visible.patch
Description: Binary data