Check wether a set of graphic handles is still valid.
isValid = is_handle_valid(h)
:h Matrix of graphic handles : :isValid Matrix of boolean with the same size as h :
is_handle_valid function tests wether a set of graphic handle is still valid. A valid handle is a handle which has not been deleted. The result, isValid, is a boolean matrix such as isValid(i,j) is true if h(i,j) is valid and false otherwise.
// check that current objects are valid
is_handle_valid([`gcf`_(), `gca`_(), `gce`_()])
// create 11 polylines
`plot`_([0:10; 0:10; 0:10], [0:10; 0:0.5:5; 0:2:20]);
// check polylines validity
axes = `gca`_();
polylines = axes.children(1).children
is_handle_valid(polylines)
// delete some polylines
`delete`_(polylines(3:7));
// print validity
is_handle_valid(polylines)