imrect() - Image Processing

h = imrect begins interactive placement
of a rectangle on the current axes. The function returns h,
a handle to an imrect object. The rectangle has
a context menu associated with it that controls aspects of its appearance
and behavior—see Interactive Behavior. Right-click on the rectangle to
access this  context menu.h = imrect(hparent) begins
interactive placement of a rectangle on the object specified by hparent. hparent specifies
the HG parent of the rectangle graphics, which is typically an axes
but can also be any other object that can be the parent of an hggroup. h = imrect(hparent, position) creates
a draggable rectangle on the object specified by hparent. position is
a four-element vector that specifies the initial size and location
of the rectangle. position has the form [xmin
ymin width height]. h = imrect(..., param1, val1,...) creates
a draggable rectangle, specifying parameters and corresponding values
that control the behavior of the rectangle. The following table lists
the parameter available. Parameter names can be abbreviated, and case
does not matter.ParameterDescription
'PositionConstraintFcn'Function handle fcn that is called
whenever the mouse is dragged. You can use this function to control
where the rectangle can be dragged. See the help for the setPositionConstraintFcn method for information
about valid function handles. 
Interactive BehaviorWhen you call imrect with an interactive
syntax, the pointer changes to a cross hairs 
when over the image. You
can create the rectangle and adjust its size and position using the
mouse. The rectangle also supports a context menu that you can use
to control aspects of its appearance and behavior. The following figure
shows the rectangle.
The following table lists the interactive behaviors supported
by imrect.Interactive BehaviorDescription
Moving the rectangle.Move the pointer inside the rectangle. The pointer changes
to a fleur shape 
.
Click and drag the mouse to move the rectangle.  
Resizing the rectangle. Move the pointer over any of the edges or corners of the rectangle,
the shape changes to a double-ended arrow, 
. Click and drag the edge
or corner using the mouse.
Changing the color of the rectangle.Move the pointer inside the rectangle. Right-click and select Set
Color from the context menu. 
Retrieving the coordinates of the current positionMove the pointer inside the polygon. Right-click and select Copy
Position from the context menu. imrect copies
a four-element position vector to the clipboard. 
Preserve the current aspect ratio of the rectangle during interactive
resizing. Move the pointer inside the rectangle. Right-click and select Fix
Aspect Ratio from the context menu.
Deleting the rectangleMove the pointer inside the rectangle or on an edge of the
rectangle. Right-click and select Delete  from
the context menu. To remove this option from the context menu, set
the Deletable property to false: h = imrect();
h.Deletable = false;
MethodsEach imrect object supports a number of methods,
listed below. Type methods imrect to see a list
of the methods. addNewPositionCallback — Add new-position callback to ROI  objectSee imroi for information.createMask — Create mask within imageSee imroi for information.delete — Delete ROI objectSee imroi for information.getColor — Get color used to draw ROI objectSee imroi for information.getPosition — Return current position of rectanglepos = getPosition(h) returns the current
position of the rectangle h. The returned position, pos,
is a 1-by-4 array [xmin ymin width height].getPositionConstraintFcn — Return function handle to current  position constraint functionSee imroi for information.removeNewPositionCallback — Remove new-position callback
from  ROI object.See imroi for information.resume — Resume execution of MATLAB command lineSee imroi for information.setColor — Set color used to draw ROI objectSee imroi for information.setConstrainedPosition — Set ROI object to new positionSee imroi for information.setFixedAspectRatioMode — Control whether aspect ratio
 preserved during resizesetFixedAspectRatioMode(h,TF) sets the interactive
resize behavior of the rectangle h. TF is
a logical scalar. True means that the current aspect
ratio is preserved during interactive resizing. False means
that interactive resizing is not constrained.setPosition — Set rectangle to new positionsetPosition(h,pos) sets the rectangle h to
a new position. The new position, pos, has the
form [xmin ymin width height].setPositionConstraintFcn — Set position constraint function of  ROI objectSee imroi for information.setResizable — Set resize behavior of rectanglesetResizable(h,TF) sets whether the rectangle h may
be resized interactively. TF is a logical scalar.wait — Block MATLAB command line until ROI creation is  finishedSee imroi for information.

Syntax

h = imrecth = imrect(hparent)h = imrect(hparent, position)h = imrect(..., param1, val1,...)

Example

figure, imshow('cameraman.tif');
h = imrect(gca, [10 10 100 100]);
addNewPositionCallback(h,@(p) title(mat2str(p,3)));
fcn = makeConstrainToRectFcn('imrect',get(gca,'XLim'),get(gca,'YLim'));
setPositionConstraintFcn(h,fcn);

Output / Return Value

Limitations

Alternatives / See Also

Reference