MATLAB Function Reference |
You can set and query graphics object properties in two ways:
set
and get
commands enable you to set and query the values of properties.
To change the default values of properties, see Setting Default Property Values.
See Core Objects for general information about this type of object.
Light Property Descriptions
This section lists property names along with the type of values each accepts.
BeingDeleted
on | {off}
Read Only
This object is being deleted. The BeingDeleted
property provides a mechanism that you can use to determine if objects are in the process of being deleted. MATLAB sets the BeingDeleted
property to on
when the object's delete function callback is called (see the DeleteFcn
property). It remains set to on
while the delete function executes, after which the object no longer exists.
For example, an object's delete function might call other functions that act on a number of different objects. These functions may not need to perform actions on objects that are going to be deleted and, therefore, can check the object's BeingDeleted
property before acting.
BusyAction
cancel | {queue}
Callback routine interruption. The BusyAction
property enables you to control how MATLAB handles events that potentially interrupt executing callback routines. If there is a callback routine executing, callback routines invoked subsequently always attempt to interrupt it. If the Interruptible
property of the object whose callback is executing is set to on
(the default), then interruption occurs at the next point where the event queue is processed. If the Interruptible
property is off
, the BusyAction
property (of the object owning the executing callback) determines how MATLAB handles the event. The choices are
cancel
-- Discard the event that attempted to execute a second callback routine.
queue
-- Queue the event that attempted to execute a second callback routine until the current callback finishes.
ButtonDownFcn
string
This property is not useful on lights.
Children
handles
The empty matrix; light objects have no children.
Clipping
on | off
Clipping
has no effect on light objects.
Color
ColorSpec
Color of light. This property defines the color of the light emanating from the light object. Define it as a three-element RGB vector or one of the MATLAB predefined names. See the ColorSpec
reference page for more information.
CreateFcn
string or function handle
Callback routine executed during object creation. This property defines a callback routine that executes when MATLAB creates a light object. You must define this property as a default value for lights or in a call to the light
function to create a new light object. For example, the statement
sets the current figure colormap to hsv
whenever you create a light object. MATLAB executes this routine after setting all light properties. Setting this property on an existing light object has no effect.
The handle of the object whose CreateFcn
is being executed is accessible only through the root CallbackObject
property, which you can query using gcbo
.
See Function Handle Callbacks for information on how to use function handles to define the callback function.
DeleteFcn
string or function handle
Delete light callback routine. A callback routine that executes when you delete the light object (i.e., when you issue a delete
command or clear the axes or figure containing the light). MATLAB executes the routine before destroying the object's properties so these values are available to the callback routine.
The handle of the object whose DeleteFcn
is being executed is accessible only through the root CallbackObject
property, which you can query using gcbo
.
See Function Handle Callbacks for information on how to use function handles to define the callback function.
HandleVisibility
{on} | callback | off
Control access to object's handle by command-line users and GUIs. This property determines when an object's handle is visible in its parent's list of children. HandleVisibility
is useful for preventing command-line users from accidentally drawing into or deleting a figure that contains only user interface devices (such as a dialog box).
Handles are always visible when HandleVisibility
is on
.
Setting HandleVisibility
to callback
causes handles to be visible from within callback routines or functions invoked by callback routines, but not from within functions invoked from the command line. This provides a means to protect GUIs from command-line users, while allowing callback routines to have complete access to object handles.
Setting HandleVisibility
to off
makes handles invisible at all times. This may be necessary when a callback routine invokes a function that might potentially damage the GUI (such as evaluating a user-typed string), and so temporarily hides its own handles during the execution of that function.
When a handle is not visible in its parent's list of children, it cannot be returned by functions that obtain handles by searching the object hierarchy or querying handle properties. This includes get
, findobj
, gca
, gcf
, gco
, newplot
, cla
, clf
, and close
.
When a handle's visibility is restricted using callback
or off
, the object's handle does not appear in its parent's Children
property, figures do not appear in the root's CurrentFigure
property, objects do not appear in the root's CallbackObject
property or in the figure's CurrentObject
property, and axes do not appear in their parent's CurrentAxes
property.
You can set the root ShowHiddenHandles
property to on
to make all handles visible regardless of their HandleVisibility
settings (this does not affect the values of the HandleVisibility
properties).
Handles that are hidden are still valid. If you know an object's handle, you can set
and get
its properties, and pass it to any function that operates on handles.
HitTest
{on} | off
This property is not used by light objects.
Interruptible
{on} | off
Callback routine interruption mode. Light object callback routines defined for the DeleteFcn
property are not affected by the Interruptible
property.
Parent
handle of parent axes, hggroup,or hgtransform
Parent of light object. This property contains the handle of the light object's parent. The parent of a light object is the axes, hggroup, or hgtransform object that contains it.
See Objects That Can Contain Other Objects for more information on parenting graphics objects.
Position
[x,y,z]
in axes data units
Location of light object. This property specifies a vector defining the location of the light object. The vector is defined from the origin to the specified x-, y-, and z-coordinates. The placement of the light depends on the setting of the Style
property:
Style
property is set to local
, Position
specifies the actual location of the light (which is then a point source that radiates from the location in all directions).
Style
property is set to infinite
, Position
specifies the direction from which the light shines in parallel rays.
Selected
on | off
This property is not used by light objects.
SelectionHighlight
{on} | off
This property is not used by light objects.
Style
{infinite} | local
Parallel or divergent light source. This property determines whether MATLAB places the light object at infinity, in which case the light rays are parallel, or at the location specified by the Position
property, in which case the light rays diverge in all directions. See the Position
property.
Tag
string
User-specified object label. The Tag
property provides a means to identify graphics objects with a user-specified label. This is particularly useful when you are constructing interactive graphics programs that would otherwise need to define object handles as global variables or pass them as arguments between callback routines. You can define Tag
as any string.
Type
string (read only)
Type of graphics object. This property contains a string that identifies the class of graphics object. For light objects, Type
is always 'light'
.
UIContextMenu
handle of a uicontextmenu object
This property is not used by light objects.
UserData
matrix
User-specified data. This property can be any data you want to associate with the light object. The light does not use this property, but you can access it using set
and get
.
Visible
{on} | off
Light visibility. While light objects themselves are not visible, you can see the light on patch and surface objects. When you set Visible
to off
, the light emanating from the source is not visible. There must be at least one light object in the axes whose Visible
property is on
for any lighting features to be enabled (including the axes AmbientLightColor
and patch and surface AmbientStrength
).
light | lightangle |
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