Image Properties

Raster image appearance and behavior

Since R2026a

expand all in page

Image properties control the appearance and behavior of Image objects. By changing property values, you can modify certain aspects of the object. Use dot notation to query and set properties.

[A,R] = readBasemapImage("darkwater",[42 -73]);
im = geoimage(A,R);
a = im.AlphaData;
im.AlphaData = 0.5;

Create an image from raster data in geographic or projected coordinates by using the geoimage function.

Color and Transparency

expand all

Color data, specified as a matrix or an m-by-n-by-3 array of RGB triplets.

  • A matrix defines grayscale image data, where each element of the matrix specifies a color for one element of the raster. The elements of ColorData map to colors in a grayscale colormap. The interpretation of ColorData depends on the data type.

    • If ColorData is of type single or double, then 0 corresponds to black and 1 corresponds to white. NaN values are completely transparent.

    • If ColorData is an integer type, then the image uses the full range of data to determine the color. For example, if ColorData is of type uint8, then 0 corresponds to black and 255 corresponds to white. If ColorData is of type int8, then -128 corresponds to black and 127 corresponds to white.

    • If ColorData is of type logical, then 0 corresponds to black and 1 corresponds to white.

  • An m-by-n-by-3 array of RGB triplets defines true color image data, where each triplet specifies a color for one element of the raster. An RGB triplet is a three-element vector that specifies the intensities of the red, green and blue components of the color. The interpretation of each RGB triplet in ColorData depends on the data type.

    • If ColorData is of type single or double, then [0 0 0] corresponds to black and [1 1 1] corresponds to white.

    • If ColorData is an integer type, then the image uses the full range of data to determine the color. For example, if ColorData is of type uint8, then [0 0 0] corresponds to black and [255 255 255] corresponds to white. If ColorData is of type int8, then [-128 -128 -128] corresponds to black and [127 127 127] corresponds to white.

    • If ColorData is of type logical, then [0 0 0] corresponds to black and [1 1 1] corresponds to white.

The height and width of ColorData must match the raster size reported by the raster reference object in RasterReference. For a raster reference object R, you can find the raster size by querying the RasterSize property of the object, such as R.RasterSize.

When you pass an image to the geoimage function, the function sets the value of ColorData.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

Transparency data, specified as one of these options:

  • A scalar — Use a consistent transparency across the entire image.

  • A matrix — Each element of the matrix specifies the transparency for the corresponding element of the image. The height and width of the matrix must match the height and width of ColorData.

The interpretation of AlphaData depends on the data type:

  • If AlphaData is of type single or double, then a value of 0 or less is completely transparent and a value of 1 or greater is opaque. Values between 0 and 1 are semitransparent.

  • If AlphaData is an integer type, then the object uses the full range of data to determine the transparency. For example, if AlphaData is of type int8, then -128 is completely transparent and 127 is opaque. Values between -128 and 127 are semitransparent.

  • If AlphaData is of type logical, then 0 is completely transparent and 1 is opaque.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

Value indicating missing data, specified as one of these options:

  • A numeric scalar, when ColorData is a matrix.

  • A 1-by-3 numeric vector, when ColorData is an m-by-n-by-3 array of RGB triplets.

When a matrix element or RGB triplet in ColorData matches the missing data value, the corresponding element of the image appears transparent, regardless of the value of AlphaData.

Interpolation method for displaying the image, specified as one of these options:

  • 'bilinear' — Bilinear interpolation. Use this method to display an image with a smoother appearance. MATLAB® displays each image element by calculating a weighted average of the surrounding image elements.

  • 'nearest' — Nearest-neighbor interpolation. Use this method when the image has a small number of colors that represent distinct categories, or when you want to see individual image elements in a highly zoomed-in view. The value of a displayed image element is the value of the closest image element in the ColorData property of the image.

The value of Interpolation does not affect the data stored in the ColorData or AlphaData properties of the image.

Position

expand all

Raster reference, specified as a GeographicCellsReference, GeographicPostingsReference, MapCellsReference, or MapPostingsReference object. The RasterSize property of the raster reference object must match the height and width of ColorData.

For MapCellsReference and MapPostingsReference objects, the ProjectedCRS property must not be empty.

For GeographicCellsReference and GeographicPostingsReference objects, if the GeographicCRS property is empty, then the object assumes the geographic coordinate reference system (CRS) based on the type of axes into which you plot the data:

  • Geographic axes — The WGS84 CRS.

  • Map axes — The geographic CRS specified by the ProjectedCRS property of the map axes. To find the geographic CRS, access the projected CRS in the ProjectedCRS property. Then, access the GeographicCRS property of the projected CRS. For example, to find the geographic CRS for a map axes mx, query mx.ProjectedCRS.GeographicCRS.

When you pass a raster reference object to the geoimage function, the function sets the value of RasterReference.

Include the image in the automatic selection of the axes limits, specified as "on" or "off", or as a 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 reference object associated with the image defines the location of the image.

By default, the axes limits automatically change to include the data range for each successive chart you create in the axes. Setting this property enables you to focus on the range of a subset of data. To exclude the data range of an image from the automatic selection, set its AffectAutoLimits property to "off".

Image with AffectAutoLimits Set to "on" Image with AffectAutoLimits Set to "off"

An image and a scatter chart in the same geographic axes. The bounds of the image are larger than the bounds of the scatter chart.

The same image and scatter chart. The limits of the geographic axes are reduced to the bounds of the scatter chart.

Interactivity

expand all

State of visibility, 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.

  • 'on' — Display the object.

  • 'off' — Hide the object without deleting it. You still can access the properties of an invisible object.

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

Note

If the PickableParts property is set to 'none' or if the HitTest property is set to 'off', then the context menu does not appear.

Selection state, 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.

  • "on" — Selected. If you click the object when in plot edit mode, then MATLAB sets its Selected property to "on". If the SelectionHighlight property also is set to "on", then MATLAB displays selection handles around the object.

  • "off" — Not selected.

Display of selection handles when selected, 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.

  • "on" — Display selection handles when the Selected property is set to "on".

  • "off" — Never display selection handles, even when the Selected property is set to "on".

Callbacks

expand all

Mouse-click callback, specified as one of these values:

  • Function handle

  • Cell array containing a function handle and additional arguments

  • String scalar or character vector that is a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

The ButtonDownFcn callback executes when you click the Image object.

For more information on how to use function handles to define callback functions, see Create Callbacks for Graphics Objects.

Note

If the PickableParts property is set to "none" or if the HitTest property is set to "off", then this callback does not execute.

Object creation function, specified as one of these values:

  • Function handle

  • Cell array in which the first element is a function handle and subsequent elements are the arguments to pass to the callback function

  • String scalar or character vector containing a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

For more information about specifying a callback as a function handle, cell array, string scalar, or character vector, see Create Callbacks for Graphics Objects.

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.

Object deletion function, specified as one of these values:

  • Function handle

  • Cell array in which the first element is a function handle and subsequent elements are the arguments to pass to the callback function

  • String scalar or character vector containing a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

For more information about specifying a callback as a function handle, cell array, string scalar, or character vector, see Create Callbacks for Graphics Objects.

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

expand all

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.

MATLAB determines callback interruption behavior whenever it executes a command that processes the callback queue. These commands include drawnow, figure, uifigure, getframe, waitfor, and pause.

If the running callback does not contain one of these commands, then no interruption occurs. MATLAB first finishes executing the running callback, and later executes the interrupting callback.

If the running callback does contain one of these commands, then the Interruptible property of the object that owns the running callback determines if the interruption occurs:

  • If the value of Interruptible is set to "off", then no interruption occurs. Instead, the BusyAction property of the object that owns the interrupting callback determines if the interrupting callback is discarded or added to the callback queue.

  • If the value of Interruptible is set to "on", then the interruption occurs. The next time MATLAB processes the callback queue, it stops the execution of the running callback and executes the interrupting callback. After the interrupting callback completes, MATLAB then resumes executing the running callback.

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.

  • If the interrupting callback is owned by a Timer object, then the callback executes according to schedule regardless of the Interruptible property value.

Note

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.

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.

The BusyAction property determines callback queuing behavior only when both of these conditions are met:

  • The running callback contains a command that processes the callback queue, such as drawnow, figure, uifigure, getframe, waitfor, or pause.

  • The value of the Interruptible property of the object that owns the running callback is set to "off".

Under these conditions, the BusyAction property of the object that owns the interrupting callback determines how MATLAB handles the interrupting callback. Specify the BusyAction property as one of these values:

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

  • "cancel" — Do not execute the interrupting callback.

Ability to capture mouse clicks, specified as one of these values:

  • 'visible' — Capture mouse clicks only when visible. The Visible property must be set to 'on'. The HitTest property determines if the Image object responds to the click or if an ancestor does.

  • 'none' — Cannot capture mouse clicks. Clicking the Image object passes the click to the object behind it in the current view of the figure window. The HitTest property of the Image object has no effect.

Response to captured mouse clicks, 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.

  • "on" — Trigger the ButtonDownFcn callback of the Image object. If you have defined the ContextMenu property, then invoke the context menu.

  • "off" — Trigger the callbacks for the nearest ancestor of the Image object that meets one of these conditions:

    • HitTest property is set to "on".

    • PickableParts property is set to a value that enables the ancestor to capture mouse clicks.

Note

The PickableParts property determines if the Image object can capture mouse clicks. If it cannot, then the HitTest property has no effect.

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

expand all

Parent, specified as a GeographicAxes object or MapAxes object.

The object has no children. You cannot set this property.

Visibility of the object handle in the Children property of the parent, specified as one of these values:

  • 'on' — Object handle is always visible.

  • 'off' — Object handle is invisible at all times. This option is useful for preventing unintended changes by another function. Set the HandleVisibility to 'off' to temporarily hide the handle during the execution of that function.

  • 'callback' — Object handle 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 permits callback functions to access it.

If the object is not listed in the Children property of the parent, then functions that obtain object handles by searching the object hierarchy or querying handle properties cannot return it. Examples of such functions include the get, findobj, gca, gcf, gco, newplot, cla, clf, and close functions.

Hidden object handles are still valid. Set the root ShowHiddenHandles property to 'on' to list all object handles regardless of their HandleVisibility property setting.

Identifiers

expand all

This property is read-only.

Type of graphics object, returned as 'rasterimage'.

Object identifier, specified as a string scalar or character vector. 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.

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 a Single App Designer App.

Version History

Introduced in R2026a

See Also

Functions

Topics