— Function File: hggroup ()
— Function File: hggroup (h)
— Function File: hggroup (..., property, value, ...)

Create group object with parent h. If no parent is specified, the group is created in the current axes. Return the handle of the group object created.

Multiple property-value pairs may be specified for the group, but they must appear in pairs.

     x = 0:0.1:10;
     hg = hggroup ();
     plot (x, sin (x), "color", [1, 0, 0], "parent", hg);
     hold on
     plot (x, cos (x), "color", [0, 1, 0], "parent", hg);
     set (hg, "visible", "off");

— Built-in Function: addproperty (name, h, type)
— Built-in Function: addproperty (name, h, type, arg, ...)

Create a new property named name in graphics object h. type determines the type of the property to create. args usually contains the default value of the property, but additional arguments might be given, depending on the type of the property.

The supported property types are:

string

A string property. arg contains the default string value.

any

An un-typed property. This kind of property can hold any octave value. args contains the default value.

radio

A string property with a limited set of accepted values. The first argument must be a string with all accepted values separated by a vertical bar ('|'). The default value can be marked by enclosing it with a '{' '}' pair. The default value may also be given as an optional second string argument.

boolean

A boolean property. This property type is equivalent to a radio property with "on|off" as accepted values. arg contains the default property value.

double

A scalar double property. arg contains the default value.

handle

A handle property. This kind of property holds the handle of a graphics object. arg contains the default handle value. When no default value is given, the property is initialized to the empty matrix.

data

A data (matrix) property. arg contains the default data value. When no default value is given, the data is initialized to the empty matrix.

color

A color property. arg contains the default color value. When no default color is given, the property is set to black. An optional second string argument may be given to specify an additional set of accepted string values (like a radio property).

type may also be the concatenation of a core object type and a valid property name for that object type. The property created then has the same characteristics as the referenced property (type, possible values, hidden state...). This allows to clone an existing property into the graphics object h.

Examples:

          addproperty ("my_property", gcf, "string", "a string value");
          addproperty ("my_radio", gcf, "radio", "val_1|val_2|{val_3}");
          addproperty ("my_style", gcf, "linelinestyle", "--");

— Built-in Function: addlistener (h, prop, fcn)

Register fcn as listener for the property prop of the graphics object h. Property listeners are executed (in order of registration) when the property is set. The new value is already available when the listeners are executed.

prop must be a string naming a valid property in h.

fcn can be a function handle, a string or a cell array whose first element is a function handle. If fcn is a function handle, the corresponding function should accept at least 2 arguments, that will be set to the object handle and the empty matrix respectively. If fcn is a string, it must be any valid octave expression. If fcn is a cell array, the first element must be a function handle with the same signature as described above. The next elements of the cell array are passed as additional arguments to the function.

Example:

          function my_listener (h, dummy, p1)
            fprintf ("my_listener called with p1=%s\n", p1);
          endfunction
          
          addlistener (gcf, "position", {@my_listener, "my string"})

— Built-in Function: dellistener (h, prop, fcn)

Remove the registration of fcn as a listener for the property prop of the graphics object h. The function fcn must be the same variable (not just the same value), as was passed to the original call to addlistener.

If fcn is not defined then all listener functions of prop are removed.

Example:

          function my_listener (h, dummy, p1)
            fprintf ("my_listener called with p1=%s\n", p1);
          endfunction
          
          c = {@my_listener, "my string"};
          addlistener (gcf, "position", c);
          dellistener (gcf, "position", c);

     x = 0:0.1:10;
     hg = hggroup ();
     h = plot (x, sin (x), "color", [1, 0, 0], "parent", hg);
     addproperty ("linestyle", hg, "linelinestyle", get (h, "linestyle"));
     addlistener (hg, "linestyle", @update_props);
     hold on
     plot (x, cos (x), "color", [0, 1, 0], "parent", hg);
     
     function update_props (h, d)
       set (get (h, "children"), "linestyle", get (h, "linestyle"));
     endfunction

     x = 0:0.1:10;
     hg = hggroup ();
     h1 = plot (x, sin (x), "color", [1, 0, 0], "parent", hg);
     addproperty ("linestyle", hg, "linelinestyle", get (h, "linestyle"));
     hold on
     h2 = plot (x, cos (x), "color", [0, 1, 0], "parent", hg);
     hlink = linkprop ([hg, h1, h2], "color");

— Function File: hlink = linkprop (h, prop)

Link graphics object properties, such that a change in one is propagated to the others. The properties to link are given as a string of cell string array by prop and the objects containing these properties by the handle array h.

An example of the use of linkprop is

          x = 0:0.1:10;
          subplot (1, 2, 1);
          h1 = plot (x, sin (x));
          subplot (1, 2, 2);
          h2 = plot (x, cos (x));
          hlink = linkprop ([h1, h2], {"color","linestyle"});
          set (h1, "color", "green");
          set (h2, "linestyle", "--");

     h = stem (1:4)
     get (h, "xdata")
     ⇒ [  1   2   3   4]'
     get (get (h, "children")(1), "xdata")
     ⇒ [  1   1 NaN   2   2 NaN   3   3 NaN   4   4 NaN]'