Altimeter Properties

Control altimeter appearance and behavior

Altimeters are components that represent an altimeter. Properties control the appearance and behavior of an altimeter. Use dot notation to refer to a particular object and property:

f = uifigure;
altimeter = uiaeroaltimeter(f);
altimeter.Altitude = 100;

The altimeter displays the altitude above sea level in feet, also known as the pressure altitude. It displays the altitude value with needles on a gauge and a numeric indicator.

• The gauge has 10 major ticks. Within each major tick are five minor ticks. This gauge has three needles. Using the needles, the altimeter can display accurately only altitudes between 0 and 100,000 feet.

  • For the longest needle, an increment of a small tick represents 20 feet and a major tick represents 100 feet.

  • For the second longest needle, a minor tick represents 200 feet and a major tick represents 1,000 feet.

  • For the shortest needle a minor tick represents 2,000 feet and a major tick represents 10,000 feet.

• For the numeric display, the gauge shows values as numeric characters between 0 and 9,999 feet. When the numeric display value reaches 10,000 feet, the gauge displays the value as the remaining values below 10,000 feet. For example, 12,345 feet displays as 2,345 feet. When a value is less than 0 (below sea level), the gauge displays 0. The needles show the appropriate value except for when the value is below sea level or over 100000 feet. Below sea level, the needles set to 0, over 100,000, the needles stay set at 100,000.

Altimeter

Altitude — Altitude of aircraft

0 (default) | finite, real, and scalar numeric

Altitude of the aircraft, specified as any finite and scalar numeric, in feet.

Example: 60

Dependencies

Specifying this value changes the value of Value.

Data Types: double

Value — Location of aircraft heading

0 (default) | finite, real, and scalar numeric

Location of the aircraft altitude, specified as a finite and scalar numeric, in feet.

• Changing the value changes the direction of the heading in 5-degree increments.

Example: 60

Dependencies

Specifying this value changes the value of the Altitude value.

Data Types: double

Interactivity

Visible — Visibility of altimeter

'on' (default) | on/off logical value

Visibility of the altimeter, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState. The Visible property determines whether the altimeter is displayed on the screen. If the Visible property is set to 'off', then the entire altimeter is hidden, but you can still specify and access its properties.

ContextMenu — Context menu

empty GraphicsPlaceholder array (default) | ContextMenu object

Context menu, specified as a ContextMenu object created using the uicontextmenu function. Use this property to display a context menu when you right-click on a component.

Enable — Operational state of altimeter

'on' (default) | on/off logical value

Operational state of altimeter, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

• If you set this property to 'on', then the appearance of the altimeter indicates that the altimeter is operational.

• If you set this property to 'off', then the appearance of the altimeter appears dimmed, indicating that the altimeter is not operational.

Position

Position — Location and size of altimeter

[100 100 120 120] (default) | [left bottom width height]

Location and size of the altimeter relative to the parent container, specified as the vector, [left bottom width height]. This table describes each element in the vector.

Element	Description
left	Distance from the inner left edge of the parent container to the outer left edge of an imaginary box surrounding the altimeter
bottom	Distance from the inner bottom edge of the parent container to the outer bottom edge of an imaginary box surrounding the altimeter
width	Distance between the right and left outer edges of the altimeter
height	Distance between the top and bottom outer edges of the altimeter

All measurements are in pixel units.

The Position values are relative to the drawable area of the parent container. The drawable area is the area inside the borders of the container and does not include the area occupied by decorations such as a menu bar or title.

Example: [200 120 120 120]

InnerPosition — Inner location and size of altimeter

[100 100 120 120] (default) | [left bottom width height]

Inner location and size of the altimeter, specified as [left bottom width height]. Position values are relative to the parent container. All measurements are in pixel units. This property value is identical to the Position property.

OuterPosition — Outer location and size of altimeter

[100 100 120 120]] (default) | [left bottom width height]

This property is read-only.

Outer location and size of the altimeter returned as [left bottom width height]. Position values are relative to the parent container. All measurements are in pixel units. This property value is identical to the Position property.

Layout — Layout options

empty LayoutOptions array (default) | GridLayoutOptions object

Layout options, specified as a GridLayoutOptions object. This property specifies options for components that are children of grid layout containers. If the component is not a child of a grid layout container (for example, it is a child of a figure or panel), then this property is empty and has no effect. However, if the component is a child of a grid layout container, you can place the component in the desired row and column of the grid by setting the Row and Column properties on the GridLayoutOptions object.

For example, this code places an altimeter in the third row and second column of its parent grid.

g = uigridlayout([4 3]);
gauge = uiaeroaltimeter(g);
gauge.Layout.Row = 3;
gauge.Layout.Column = 2;

To make the altimeter span multiple rows or columns, specify the Row or Column property as a two-element vector. For example, this altimeter spans columns 2 through 3:

gauge.Layout.Column = [2 3];

Callbacks

CreateFcn — Creation function

'' (default) | function handle | cell array | character vector

Object creation function, specified as one of these values:

• Function handle.

• Cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• Character vector containing a valid MATLAB^® expression (not recommended). MATLAB evaluates this expression in the base workspace.

For more information about specifying a callback as a function handle, cell array, or character vector, see Write Callbacks in App Designer.

This property specifies a callback function to execute when MATLAB creates the object. MATLAB initializes all property values before executing the CreateFcn callback. If you do not specify the CreateFcn property, then MATLAB executes a default creation function.

Setting the CreateFcn property on an existing component has no effect.

If you specify this property as a function handle or cell array, you can access the object that is being created using the first argument of the callback function. Otherwise, use the gcbo function to access the object.

DeleteFcn — Deletion function

'' (default) | function handle | cell array | character vector

Object deletion function, specified as one of these values:

• Function handle.

• Cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• Character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

For more information about specifying a callback as a function handle, cell array, or character vector, see Write Callbacks in App Designer.

This property specifies a callback function to execute when MATLAB deletes the object. MATLAB executes the DeleteFcn callback before destroying the properties of the object. If you do not specify the DeleteFcn property, then MATLAB executes a default deletion function.

If you specify this property as a function handle or cell array, you can access the object that is being deleted using the first argument of the callback function. Otherwise, use the gcbo function to access the object.

Callback Execution Control

Interruptible — Callback interruption

'on' (default) | on/off logical value

Callback interruption, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

This property determines if a running callback can be interrupted. There are two callback states to consider:

• The running callback is the currently executing callback.

• The interrupting callback is a callback that tries to interrupt the running callback.

Whenever MATLAB invokes a callback, that callback attempts to interrupt the running callback (if one exists). The Interruptible property of the object owning the running callback determines if interruption is allowed.

• A value of 'on' allows other callbacks to interrupt the object's callbacks. The interruption occurs at the next point where MATLAB processes the queue, such as when there is a drawnow, figure, uifigure, getframe, waitfor, or pause command.

  • If the running callback contains one of those commands, then MATLAB stops the execution of the callback at that point and executes the interrupting callback. MATLAB resumes executing the running callback when the interrupting callback completes.

  • If the running callback does not contain one of those commands, then MATLAB finishes executing the callback without interruption.

• A value of 'off' blocks all interruption attempts. The BusyAction property of the object owning the interrupting callback determines if the interrupting callback is discarded or put into a queue.

Note

Callback interruption and execution behave differently in these situations:

• If the interrupting callback is a DeleteFcn, CloseRequestFcn or SizeChangedFcn callback, then the interruption occurs regardless of the Interruptible property value.

• If the running callback is currently executing the waitfor function, then the interruption occurs regardless of the Interruptible property value.

• Timer objects execute according to schedule regardless of the Interruptible property value.

When an interruption occurs, MATLAB does not save the state of properties or the display. For example, the object returned by the gca or gcf command might change when another callback executes.

BusyAction — Callback queuing

'queue' (default) | 'cancel'

Callback queuing, specified as 'queue' or 'cancel'. The BusyAction property determines how MATLAB handles the execution of interrupting callbacks. There are two callback states to consider:

• The running callback is the currently executing callback.

• The interrupting callback is a callback that tries to interrupt the running callback.

Whenever MATLAB invokes a callback, that callback attempts to interrupt a running callback. The Interruptible property of the object owning the running callback determines if interruption is permitted. If interruption is not permitted, then the BusyAction property of the object owning the interrupting callback determines if it is discarded or put in the queue. These are possible values of the BusyAction property:

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

• 'cancel' — Does not execute the interrupting callback.

BeingDeleted — Deletion status

on/off logical value

This property is read-only.

Deletion status, returned as an on/off logical value of type matlab.lang.OnOffSwitchState.

MATLAB sets the BeingDeleted property to 'on' when the DeleteFcn callback begins execution. The BeingDeleted property remains set to 'on' until the component object no longer exists.

Check the value of the BeingDeleted property to verify that the object is not about to be deleted before querying or modifying it.

Parent/Child

HandleVisibility — Visibility of object handle

'on' (default) | 'callback' | 'off'

Visibility of the object handle, specified as 'on', 'callback', or 'off'.

This property controls the visibility of the object in its parent's list of children. When an object is not visible in its parent's list of children, it is not returned by functions that obtain objects by searching the object hierarchy or querying properties. These functions include get, findobj, clf, and close. Objects are valid even if they are not visible. If you can access an object, you can set and get its properties, and pass it to any function that operates on objects.

HandleVisibility Value	Description
'on'	The object is always visible.
'callback'	The object is visible from within callbacks or functions invoked by callbacks, but not from within functions invoked from the command line. This option blocks access to the object at the command-line, but allows callback functions to access it.
'off'	The object is invisible at all times. This option is useful for preventing unintended changes to the UI by another function. Set the HandleVisibility to 'off' to temporarily hide the object during the execution of that function.

Parent — Parent container

Figure object (default) | Panel object | Tab object | ButtonGroup object | GridLayout object

Parent container, specified as a Figure object created using the uifigure function, or one of its child containers: Tab, Panel, ButtonGroup, or GridLayout. If no container is specified, MATLAB calls the uifigure function to create a new Figure object that serves as the parent container.

Identifiers

Type — Type of graphics object

'uiaeroaltimeter'

This property is read-only.

Type of graphics object, returned as 'uiaeroaltimeter'.

Tag — Object identifier

'' (default) | character vector | string scalar

Object identifier, specified as a character vector or string scalar. You can specify a unique Tag value to serve as an identifier for an object. When you need access to the object elsewhere in your code, you can use the findobj function to search for the object based on the Tag value.

UserData — User data

[] (default) | array

User data, specified as any MATLAB array. For example, you can specify a scalar, vector, matrix, cell array, character array, table, or structure. Use this property to store arbitrary data on an object.

If you are working in App Designer, create public or private properties in the app to share data instead of using the UserData property. For more information, see Share Data Within App Designer Apps.