imline

(Not recommended) Create draggable, resizable line

imline is not recommended. Use the new Line ROI object instead. You can also use the ROI creation convenience function drawline. For more information, see Compatibility Considerations.

Description

An imline object encapsulates an interactive line over an image.

You can adjust the size and position of the line by using the mouse. The line also has a context menu that controls aspects of its appearance and behavior. For more information, see Usage.

Creation

Syntax

h = imline

h = imline(hparent)

h = imline(hparent,position)

h = imline(hparent,x,y)

h = imline(___,Name,Value)

Description

example

h = imline begins interactive placement of a line on the current axes, and returns an imline object.

h = imline(hparent) begins interactive placement of a line on the object specified by hparent.

example

h = imline(hparent,position) creates a draggable, resizeable line, with coordinates defined by position.

h = imline(hparent,x,y) creates a draggable, resizeable line, with x- and y-coordinates of the endpoints defined by x and y.

h = imline(___,Name,Value) specifies name-value pairs that control the behavior of the line.

Input Arguments

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`hparent` — Handle to parent object
handle

Handle to parent object, specified as a handle. The parent is typically an axes object, but can also be any other object that can be the parent of an hggroup object.

`position` — Position of line endpoints
2-element vector

Position of line endpoints, specified as a 2-by-2 array of the form [x1 y1; x2 y2].

`x` — x-coordinates of line endpoints
2-element vector

x-coordinates of line endpoints, specified as a 2-element vector of the form x = [x1 x2].

`y` — y-coordinates of line endpoints
2-element vector

y-coordinates of line endpoints, specified as a 2-element vector of the form y = [y1 y2].

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

`'PositionConstraintFcn'` — Position constraint function
function handle

Position constraint function, specified as the comma-separated pair consisting of 'PositionConstraintFcn' and a function handle. fcn is called whenever the mouse is dragged. You can use this function to control where the line can be dragged. See the help for the setPositionConstraintFcn function for information about valid function handles.

Properties

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`Deletable` — ROI can be deleted
`true` (default) | `false`

ROI can be deleted, specified as true or false.

Data Types: logical

Usage

When you call imline with an interactive syntax, the pointer changes to a cross hairs when over the image. Click and drag the mouse to specify the position and length of the line. The line supports a context menu that you can use to control aspects of its appearance and behavior.

The table describes the interactive behavior supported by imline.

Interactive Behavior	Description
Moving the line.	Move the pointer over the line. The pointer changes to a fleur shape . Click and drag the mouse to move the line.
Moving the endpoints of the line.	Move the pointer over either end of the line. The pointer changes to the pointing finger, . Click and drag the mouse to resize the line.
Changing the color used to display the line.	Move the pointer over the line. Right-click and select Set Color from the context menu.
Retrieving the coordinates of the endpoints of the line.	Move the pointer over the line. Right-click and select Copy Position from the context menu. `imline` copies a 2-by-2 array to the clipboard specifying the coordinates of the endpoints of the line in the form `[X1 Y1; X2 Y2]`.
Deleting the line	Move the pointer on top of the line. Right-click and select Delete from the context menu. To remove this option from the context menu, set the `Deletable` property to false: `h = imline(); h.Deletable = false;`

Object Functions

Each imline object supports a number of functions. Type methods imline to see a complete list.

`addNewPositionCallback`	Add new-position callback to ROI object
`createMask`	Create mask within image
`delete`	Delete handle object
`getColor`	Get color used to draw ROI object
`getPosition`	Return current position of ROI object
`getPositionConstraintFcn`	Return function handle to current position constraint function
`removeNewPositionCallback`	Remove new-position callback from ROI object
`resume`	(Not recommended) Resume execution of MATLAB command line
`setColor`	Set color used to draw ROI object
`setConstrainedPosition`	Set ROI object to new position
`setPosition`	(Not recommended) Move ROI object to new position
`setPositionConstraintFcn`	Set position constraint function of ROI object
`wait`	(Not recommended) Block MATLAB command line until ROI creation is finished

Examples

Update Title when Line Moves

Use a custom color for displaying the line. Use addNewPositionCallback function. Move the line, note that the 2-by-2 position vector of the line is displayed in the title above the image. Explore the context menu of the line by right clicking on the line.

imshow('pout.tif')
h = imline(gca,[10 100],[100 100]);
setColor(h,[0 1 0]);
id = addNewPositionCallback(h,@(pos) title(mat2str(pos,3)));

After observing the callback behavior, remove the callback using the removeNewPositionCallback function.

removeNewPositionCallback(h,id);

Click and Drag to Place Line

Interactively place a line by clicking and dragging. Use wait to block the MATLAB^® command line. Double-click on the line to resume execution of the MATLAB command line.

imshow('pout.tif')
h = imline;
position = wait(h);

Tips

If you use imline with an axes that contains an image object, and do not specify a position constraint function, users can drag the line outside the extent of the image and lose the line. When used with an axes created by the plot function, the axis limits automatically expand to accommodate the movement of the line.
Use imdistline to create an interactive line with a text box that displays the distance between line endpoints.

Compatibility Considerations

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`imline` is not recommended

Not recommended starting in R2018b

Starting in R2018b, a new set of ROI objects replaces the existing set of ROI objects. The new objects provide more functional capabilities, such as face color transparency. The new classes also support events that you can use to respond to changes in your ROI such as moving or being clicked. Although there are no plans to remove the old ROI objects at this time, switch to the new ROIs to take advantage of the additional capabilities and flexibility. For more information on creating ROIs using the new ROI functions, see ROI Creation Overview.

Replace use of the imline ROI object with the new Line ROI object. You can also use the ROI creation convenience function drawline.

Update ROI Creation Code

Update all instances of imline.

Discouraged Usage	Recommended Replacement
This example creates a line ROI. imshow('cameraman.tif'); h = imline(gca,[10 10; 100 150]);	Here is equivalent code, replacing the old ROI with the equivalent new ROI object. This example uses the ROI creation convenience function. Note that you must specify the size and position information as a name,value pair. imshow('cameraman.tif'); h = drawline(gca,'Position',[10 10; 100 150]);

Other ROI Code Updates

Update instances where your code uses one of the object functions of imline. In many cases, you replace the call to an object function by simply accessing or setting the value of an Line ROI object property. For example, replace calls to getColor or setColor with use of the Color property. In some cases, you must replace the imline object function with an object function of the new Line ROI. Each of the individual imline ROI object functions include information about migrating to the new Line ROI object. For a migration overview, see ROI Migration.

Documentation

imline

Description

Creation

Syntax

Description

Input Arguments

`hparent` — Handle to parent object
handle

`position` — Position of line endpoints
2-element vector

`x` — x-coordinates of line endpoints
2-element vector

`y` — y-coordinates of line endpoints
2-element vector

`'PositionConstraintFcn'` — Position constraint function
function handle

Properties

`Deletable` — ROI can be deleted
`true` (default) | `false`

Usage

Object Functions

Examples

Update Title when Line Moves

Click and Drag to Place Line

Tips

Compatibility Considerations

`imline` is not recommended

See Also

Topics

Image Processing Toolbox Documentation

Support

Documentation

imline

Description

Creation

Syntax

Description

Input Arguments

hparent — Handle to parent object handle

position — Position of line endpoints 2-element vector

x — x-coordinates of line endpoints 2-element vector

y — y-coordinates of line endpoints 2-element vector

'PositionConstraintFcn' — Position constraint function function handle

Properties

Deletable — ROI can be deleted true (default) | false

Usage

Object Functions

Examples

Update Title when Line Moves

Click and Drag to Place Line

Tips

Compatibility Considerations

imline is not recommended

See Also

Topics

Image Processing Toolbox Documentation

Support

`hparent` — Handle to parent object
handle

`position` — Position of line endpoints
2-element vector

`x` — x-coordinates of line endpoints
2-element vector

`y` — y-coordinates of line endpoints
2-element vector

`'PositionConstraintFcn'` — Position constraint function
function handle

`Deletable` — ROI can be deleted
`true` (default) | `false`

`imline` is not recommended