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Rectangle Properties

Define rectangle properties

Creating Rectangle Objects

Use rectangle to create rectangle objects.

Modifying Properties

You can set and query graphics object properties in two ways:

  • Customize Objects in Graph is an interactive tool that enables you to see and change object property values.

  • The 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 Graphics Objects for general information about this type of object.

Rectangle Property Descriptions

This section provides a description of properties. Curly braces { } enclose default values.

Annotation

hg.Annotation object (read-only)

Handle of Annotation object. The Annotation property enables you to specify whether this rectangle object is represented in a figure legend.

Querying the Annotation property returns the handle of an hg.Annotation object. The hg.Annotation object has a property called LegendInformation, which contains an hg.LegendEntry object.

Once you have obtained the hg.LegendEntry object, you can set its IconDisplayStyle property to control whether the rectangle object is displayed in a figure legend:

IconDisplayStyle ValuePurpose
onRepresent this rectangle object in a legend (default)
offDo not include this rectangle object in a legend
childrenSame as on because rectangle objects do not have children

Setting the IconDisplayStyle property

Set the IconDisplayStyle of a graphics object with handle hobj to off:

hAnnotation = get(hobj,'Annotation');
hLegendEntry = get(hAnnotation,'LegendInformation');
set(hLegendEntry,'IconDisplayStyle','off')

Using the IconDisplayStyle property

See Control Legend Content for more information and examples.

BeingDeleted

on | {off} (read-only)

This object is being deleted. Mechanism 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 calls other functions that act on a number of different objects. If a function does not need to perform an action on an about-be-deleted object, it can check the object's BeingDeleted property before acting.

BusyAction

cancel | {queue}

Callback queuing

Determines how MATLAB handles the execution of interrupting callbacks.

A running callback is the currently executing callback. The interrupting callback is the callback that tries to interrupt the running callback. The BusyAction property of the interrupting callback determines how MATLAB handles its execution. When the BusyAction property is set to:

  • 'queue' — Puts the interrupting callback in a queue to be processed after the running callback finishes execution.

  • 'cancel' — Discards the interrupting callback as MATLAB finishes execution.

For information about how the Interruptible property of the callback controls whether other callbacks can interrupt the running callback, see the Interruptible property description.

ButtonDownFcn

function handle | cell array containing function handle and additional arguments | string (not recommended)

Button press callback function. Executes whenever you press a mouse button while the pointer is over the rectangle object.

See the figure's SelectionType property to determine if modifier keys were also pressed.

Set this property to a function handle that references the callback. The function must define at least two input arguments (handle of object associated with the button down event and an event structure, which is empty for this property).

The following example shows how to access the callback object's handle as well as the handle of the figure that contains the object from the callback function.

function button_down(src,evnt)
% src - the object that is the source of the event
% evnt - empty for this property
   sel_typ = get(gcbf,'SelectionType')
   switch sel_typ 
      case 'normal'
         disp('User clicked left-mouse button')
         set(src,'Selected','on')
      case 'extend'
         disp('User did a shift-click')
         set(src,'Selected','on')
      case 'alt'
         disp('User did a control-click')
         set(src,'Selected','on')
         set(src,'SelectionHighlight','off')
   end
end

Suppose h is the handle of a rectangle object and the button_down function is on your MATLAB path. The following statement assigns the button_down function to the ButtonDownFcn property:

set(h,'ButtonDownFcn',@button_down)

For information on the syntax of callback functions, see Function Handle Callbacks.

Children

vector of handles

The empty matrix; rectangle objects have no children.

Clipping

{on} | off

Clipping mode. MATLAB clips rectangles to the axes plot box by default. If you set Clipping to off, rectangles are displayed outside the axes plot box. This can occur if you create a rectangle, set hold to on, freeze axis scaling (axis set to manual), and then create a larger rectangle.

CreateFcn

function handle | cell array containing function handle and additional arguments | string (not recommended)

Callback function executed during object creation. Executes when MATLAB creates a rectangle object. You must define this property as a default value for rectangles or in a call to the rectangle function to create a new rectangle object. For example, the statement:

set(0,'DefaultRectangleCreateFcn',@rect_create)

defines a default value for the rectangle CreateFcn property on the root level that sets the axes DataAspectRatio whenever you create a rectangle object. The callback function must be on your MATLAB path when you execute the above statement.

function rect_create(src,evnt)
% src - the object that is the source of the event 
% evnt - empty for this property
  axh = get(src,'Parent');
  set(axh,'DataAspectRatio',[1,1,1]))
end

MATLAB executes this function after setting all rectangle properties. Setting this property on an existing rectangle object has no effect. The function must define at least two input arguments (handle of object created and an event structure, which is empty for this property).

The handle of the object whose CreateFcn is being executed is passed by MATLAB as the first argument to the callback function and is also accessible through the root CallbackObject property, which you can query using gcbo.

For information on the syntax of callback functions, see Function Handle Callbacks.

Curvature

one- or two-element vector [x,y]

Amount of horizontal and vertical curvature. Specifies the curvature of the rectangle sides, which enables the shape of the rectangle to vary from rectangular to ellipsoidal. The horizontal curvature x is the fraction of width of the rectangle that is curved along the top and bottom edges. The vertical curvature y is the fraction of the height of the rectangle that is curved along the left and right edges.

The values of x and y can range from 0 (no curvature) to 1 (maximum curvature). A value of [0,0] creates a rectangle with square sides. A value of [1,1] creates an ellipse. If you specify only one value for Curvature, then the same length (in axes data units) is curved along both horizontal and vertical sides. The amount of curvature is determined by the shorter dimension.

DeleteFcn

function handle | cell array containing function handle and additional arguments | string (not recommended)

Delete rectangle callback function. Executes when you delete the rectangle object (for example, when you issue a delete command or clear the axes cla or figure clf).

For example, the following function displays object property data before the object is deleted.

function delete_fcn(src,evnt)
% src - the object that is the source of the event 
% evnt - empty for this property
   obj_tp = get(src,'Type');
   disp([obj_tp, ' object deleted'])
   disp('Its user data is:')
   disp(get(src,'UserData'))
end

MATLAB executes the function before deleting the object's properties so these values are available to the callback function. The function must define at least two input arguments (handle of object being deleted and an event structure, which is empty for this property).

The handle of the object whose DeleteFcn is being executed is passed by MATLAB as the first argument to the callback function and is also accessible through the root CallbackObject property, which you can query using gcbo.

For information on the syntax of callback functions, see Function Handle Callbacks.

DisplayName

string

String used by legend. The legend function uses the DisplayName property to label the rectangle object in the legend. The default is an empty string.

  • If you specify string arguments with the legend function, MATLAB set DisplayName to the corresponding string and uses that string for the legend.

  • If DisplayName is empty, legend creates a string of the form, ['data' n], where n is the number assigned to the object based on its location in the list of legend entries. However, legend does not set DisplayName to this string.

  • If you edit the string directly in an existing legend, MATLAB set DisplayName to the edited string.

  • If you specify a string for the DisplayName property and create the legend using the figure toolbar, then MATLAB uses the string defined by DisplayName.

  • To add a legend programmatically that uses the DisplayName string, call legend with the toggle or show option.

See Control Legend Content for more information and examples.

EdgeColor

{ColorSpec} | none

Color of the rectangle edges. Specifies the color of the rectangle edges as a color or specifies that no edges be drawn.

EraseMode

{normal} | none | xor | background

Erase mode. Controls the technique MATLAB uses to draw and erase rectangle objects. Use alternative erase modes for creating animated sequences, where control of the way individual objects are redrawn is necessary to improve performance and obtain the desired effect.

  • normal — Redraw the affected region of the display, performing the three-dimensional analysis necessary to ensure that all objects are rendered correctly. This mode produces the most accurate picture, but is the slowest. The other modes are faster, but do not perform a complete redraw and are therefore less accurate.

  • none — Do not erase the rectangle when it is moved or destroyed. While the object is still visible on the screen after erasing with EraseMode none, you cannot print it because MATLAB stores no information about its former location.

  • xor — Draw and erase the rectangle by performing an exclusive OR (XOR) with the color of the screen beneath it. This mode does not damage the color of the objects beneath the rectangle. However, the rectangle's color depends on the color of whatever is beneath it on the display.

  • background — Erase the rectangle by drawing it in the axes background Color, or the figure background Color if the axes Color is none. This damages objects that are behind the erased rectangle, but rectangles are always properly colored.

Printing with Nonnormal Erase Modes

MATLAB always prints figures as if the EraseMode of all objects is normal. This means graphics objects created with EraseMode set to none, xor, or background can look different on screen than on paper. On screen, MATLAB mathematically combines layers of colors (for example, performing an XOR on a pixel color with that of the pixel behind it) and ignore three-dimensional sorting to obtain greater rendering speed. However, these techniques are not applied to the printed output.

You can use the getframe command or other screen capture applications to create an image of a figure containing nonnormal mode objects.

FaceColor

ColorSpec | {none}

Color of rectangle face. Specifies the color of the rectangle face, which is not colored by default.

HandleVisibility

{on} | callback | off

Control access to object's handle. 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).

  • on — Handles are always visible.

  • callback — Handles are 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 access to object handles.

  • off — Handles are invisible at all times. Use this option when a callback invokes a function that could damage the GUI (such as evaluating a user-typed string). This option 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

Selectable by mouse click. Determines if the rectangle can become the current object (as returned by the gco command and the figure CurrentObject property) as a result of a mouse click on the rectangle. If HitTest is off, clicking the rectangle selects the object below it (which might be the axes containing it).

Interruptible

off | {on}

Callback routine interruption

Controls whether MATLAB can interrupt an object's callback function when subsequent callbacks attempt to interrupt it.

For Graphics objects, the Interruptible property affects only the callbacks for theButtonDownFcn property. A running callback is the currently executing callback. The interrupting callback is the callback that tries to interrupt the running callback. MATLAB handles both the callbacks based on the Interruptible property of the object of the running callback.

When the Interruptible property is set to:

  • 'off', MATLAB finishes execution of the running callback without any interruptions

  • 'on', these conditions apply:

    • If there is a drawnow, figure, getframe, waitfor, or pause command in the running callback, then MATLAB executes the interrupting callbacks which are already in the queue and returns to finish execution of the current callback.

    • If one of the above functions is not in the running callback, then MATLAB finishes execution of the current callback without any interruption.

BusyAction property of the object of interrupting callback determines whether the callback should be ignored or should be put in the queue.

Setting Interruptible property to on (default), allows a callback from other graphics objects to interrupt callback functions originating from this object.

    Note:   MATLAB does not save the state of properties or the display when an interruption occurs. For example, the handle returned by the gca or gcf command may be changed as another callback is executed.

After the function that interrupts a callback completes, the callback resumes execution where it halted when interrupted. For more information, see Control Callback Execution and Interruption.

LineStyle

{-} | -- | : | -. | none

Line style of rectangle edge.

 Line Style Specifiers Table

LineWidth

size in points

Width of the rectangle edge line. Specify this value in points. 1 point = 1/72 inch. The default value is 0.5 points.

Parent

handle of axes, hggroup, or hgtransform

Parent of rectangle object. Contains the handle of the rectangle object's parent. The parent of a rectangle object is the axes, hggroup, or hgtransform object that contains it.

Position

four-element vector [x,y,width,height]

Location and size of rectangle. Specifies the location and size of the rectangle in the data units of the axes. The point defined by x, y specifies one corner of the rectangle, and width and height define the size in units along the x- and y-axes respectively.

Selected

on | off

Is object selected? When this property is on MATLAB displays selection handles if the SelectionHighlight property is also on. You can, for example, define the ButtonDownFcn to set this property, allowing users to select the object with the mouse.

SelectionHighlight

{on} | off

Objects are highlighted when selected. When the Selected property is on, MATLAB indicates the selected state by drawing handles at each vertex. When SelectionHighlight is off, MATLAB does not draw the handles.

Tag

string

User-specified object label. Provides a means to identify graphics objects with a user-specified label. The default is an empty string.

Use the Tag property and the findobj function to manipulate specific objects within a plotting hierarchy.

Type

string (read-only)

Class of graphics object. String that identifies the class of the graphics object. Use this property to find all objects of a given type within a plotting hierarchy. For rectangle objects, Type is always 'rectangle'.

UIContextMenu

handle of uicontextmenu object

Associate a context menu with the rectangle. Assign this property the handle of a uicontextmenu object created in the same figure as the rectangle. Use the uicontextmenu function to create the context menu. MATLAB displays the context menu whenever you right-click over the rectangle.

UserData

matrix

User-specified data. Data you want to associate with the rectangle object. The default value is an empty array. MATLAB does not use this data, but you can access it using the set and get commands.

Visible

{on} | off

Rectangle visibility. By default, all rectangles are visible. When set to off, the rectangle is not visible, but still exists, and you can get and set its properties.

See Also

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