Point region of interest
images.roi.Point class creates a point region-of-interest (ROI)
object. You call the
draw method of the object to begin drawing the ROI
interactively by using your mouse.
To create a point ROI interactively, position the pointer where you want the ROI and then click and release to draw it. To delete the ROI, position the pointer over the point, right-click, and then choose Delete Point from the context menu. For more information about interactive behaviors including keyboard shortcuts, see Tips.
images.roi.Point class is a
creates an instance of
h = images.roi.Point
images.roi.Point class with default properties.
creates the ROI in the axes specified by
h = images.roi.Point(
modifies the appearance and behavior of the ROI using one or more name-value pairs to
specify properties. You can set properties using name-value pairs with or without
h = images.roi.Point(___,
ax— Parent of ROI
Parent of ROI, specified as an
Color— ROI color
ROI color, specified as a MATLAB®
[0 1 0]
Deletable— ROI can be interactively deleted via context menu
ROI can be interactively deleted via a context menu, specified as
false. When the value is
true (default), you
can delete the ROI via the context menu. To disable this context menu item, set this
false. When the value is set to
you can still delete the ROI by calling the
specifying the handle to the ROI as the input.
DrawingArea— Area of axes in which you can interactively place ROI
Area of the axes in which you can interactively place the ROI, specified as one of the values in this table.
|The drawing area is the current axes limits (default).|
|The drawing area has no boundary and ROIs can be drawn or dragged to extend beyond the axes limits.|
|The drawing area is restricted to a rectangular region beginning at (x,y), and extending to width w and height h.|
HandleVisibility— Visibility of ROI handle in
Childrenproperty of parent
Visibility of the ROI handle in the
Children property of the parent,
specified as one of the values in this table.
|The object handle is always visible (default).|
|The object handle is hidden at all times.|
|The object handle is visible from within callbacks or functions invoked by callbacks, but not from within functions invoked from the command line.|
InteractionsAllowed— Interactivity of ROI
Interactivity of the ROI, specified as one of the values in this table.
|The ROI is fully interactable (default).|
|The ROI is not interactable, and no drag points are visible.|
|The ROI can be translated (moved) within the drawing area but not
reshaped. This value is not available for use with
|The ROI can be reshaped but not translated. This value is not
available for use with |
Label— ROI label
''(default) | character vector | string
ROI label, specified as a character vector or string. By default, the ROI has no label
LineWidth— Width of ROI edge
Width of the ROI edge, specified as a positive numeric scalar in points. The default value is three times the number of points per screen pixel.
Parent— ROI parent
ROI parent, specified as an
Axes object. A
be the parent of the ROI.
Position— Position of ROI
Position of the ROI, specified as a 1-by-2 numeric array of the form
y], where x and y specify the
location of the point. You can modify this property by drawing or moving the
Selected— Selection state of ROI
Selection state of the ROI, specified as the logical value
false. You can also set this property interactively. For example,
clicking on the ROI selects the ROI and sets this property to
Similarly, pressing the Ctrl key and clicking the ROI deselects the ROI
and sets the value of this property to
SelectedColor— Color of ROI when selected
Color of the ROI when selected, specified as a MATLAB
ColorSpec (Color Specification). The
intensities must be in the range
'SelectedColor' is set to
'none', then the
Color defines the color of the ROI for all states,
selected or not.
[0 1 0]
StripeColor— Color of ROI stripe
Color of the ROI stripe, specified as a MATLAB
ColorSpec (Color Specification) value.
By default, the edge of an ROI is solid colored. If you specify
StripeColor, the ROI edge is striped. The striping consists of a
combination of the value specified by
'Color' and this
[0 1 0]
Tag— Tag to associate with the ROI
''(default) | character vector | string scalar
Tag to associate with the ROI, specified as a character vector or string. Use the tag value to
find the ROI object in a hierarchy of objects using the
UIContextMenu— Context menu
Context menu, specified as a
ContextMenu object. Use this property to
display a custom context menu when you right-click the ROI. You
can create a custom context menu by using the
uicontextmenu function and then
configuring context menu properties.
UserData— Data to associate with ROI
Data to associate with the ROI, specified as any MATLAB data. For example, you can specify a scalar, vector, matrix, cell array, string, character array, table, or structure. MATLAB does not use this data.
Visible— ROI visibility
ROI visibility, specified as one of the values in this table.
|Display the ROI (default).|
|Hide the ROI without deleting it. You still can access the properties of an invisible ROI.|
|Event Name||Trigger||Event Data||Event Attributes|
|ROI is about to be interactively deleted.|
|ROI is about to be interactively drawn.|
|ROI has been interactively drawn.|
|ROI shape or location is being interactively changed.|
|ROI shape or location has been interactively changed.|
|ROI has been clicked.|
Read an image into the workspace and display it.
I = imread('baby.jpg'); figure; imshow(I)
Create a point ROI on the image, using the
'Position' property to specify the location. For programmatically created ROIs, if you want the ROI drawn in a specific axes, you must specify that axes as an input argument. Otherwise, an instance of the
images.roi.Point class is created but not displayed. In this example, specify the current axes (gca) to draw the ROI on the image in that axes.
h = images.roi.Point(gca,'Position',[400 650]);
The ROI supports the following interactivity, including keyboard shortcuts.
|Stop drawing.||Press Esc. The function returns a valid ROI object with an
|Move the ROI.||Position the pointer over the ROI. The pointer changes to a circle. Click and drag to move the ROI.|
For information about using an ROI in an app created with App Designer, see Using ROIs in Apps Created with App Designer.