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Contourgroup Properties - Define contourgroup properties

Modifying Properties

You can set and query graphics object properties using the set and get commands or the Property Editor (propertyeditor).

Note that you cannot define default properties for contourgroup objects.

See Plot Objects for more information on contourgroup objects.

Contourgroup Property Descriptions

This section provides a description of properties. Curly braces { } enclose default values.

Annotation

hg.Annotation object Read Only

Control the display of contourgroup objects in legends. The Annotation property enables you to specify whether this contourgroup object is represented in a figure legend.

Querying the Annotation property returns the handle of an hg.Annotation object. The hg.Annotation object has a property called LegendInformation, which contains an hg.LegendEntry object.

Once you have obtained the hg.LegendEntry object, you can set its IconDisplayStyle property to control whether the contourgroup object is displayed in a figure legend:

IconDisplayStyle Value	Purpose
`on`	Include the contourgroup object in a legend as one entry, but not its children objects
`off`	Do not include the contourgroup or its children in a legend (default)
`children`	Include only the children of the contourgroup as separate entries in the legend

Setting the IconDisplayStyle Property

These commands set the IconDisplayStyle of a graphics object with handle hobj to children, which causes each child object to have an entry in the legend:

hAnnotation = get(hobj,'Annotation');
hLegendEntry = get(hAnnotation,'LegendInformation');
set(hLegendEntry,'IconDisplayStyle','children')

Using the IconDisplayStyle Property

See Controlling Legends for more information and examples.

BeingDeleted

on | {off} Read Only

This object is being deleted. The BeingDeleted property provides a mechanism that you can use to determine if objects are in the process of being deleted. MATLAB sets the BeingDeleted property to on when the object's delete function callback is called (see the DeleteFcn property). It remains set to on while the delete function executes, after which the object no longer exists.

For example, an object's delete function might call other functions that act on a number of different objects. These functions might not need to perform actions on objects if the objects are going to be deleted, and therefore, can check the object's BeingDeleted property before acting.

BusyAction

cancel | {queue}

Callback routine interruption. The BusyAction property enables you to control how MATLAB handles events that potentially interrupt executing callbacks. If there is a callback function executing, callbacks invoked subsequently always attempt to interrupt it.

If the Interruptible property of the object whose callback is executing is set to on (the default), then interruption occurs at the next point where the event queue is processed. If the Interruptible property is off, the BusyAction property (of the object owning the executing callback) determines how MATLAB handles the event. The choices are

cancel — Discard the event that attempted to execute a second callback routine.
queue — Queue the event that attempted to execute a second callback routine until the current callback finishes.

ButtonDownFcn

string or function handle

Button press callback function. A callback that executes whenever you press a mouse button while the pointer is over this object, but not over another graphics object. See the HitTestArea property for information about selecting objects of this type.

See the figure's SelectionType property to determine if modifier keys were also pressed.

This property can be

A string that is a valid MATLAB expression
The name of an M-file
A function handle

Set this property to a function handle that references the callback. The expressions execute in the MATLAB workspace.

See Function Handle Callbacks for information on how to use function handles to define the callbacks.

Children

array of graphics object handles

Children of this object. The handle of a patch object that is the child of this object (whether visible or not).

Note that if a child object's HandleVisibility property is set to callback or off, its handle does not show up in this object's Children property unless you set the root ShowHiddenHandles property to on:

set(0,'ShowHiddenHandles','on')

Clipping

{on} | off

Clipping mode. MATLAB clips graphs to the axes plot box by default. If you set Clipping to off, portions of graphs can be displayed outside the axes plot box. This can occur if you create a plot object, set hold to on, freeze axis scaling (axis manual), and then create a larger plot object.

ContourMatrix

2-by-n matrix Read Only

A two-row matrix specifying all the contour lines. Each contour line defined in the ContourMatrix begins with a column that contains the value of the contour (specified by the LevelList property and is used by clabel), and the number of (x,y) vertices in the contour line. The remaining columns contain the data for the (x,y) pairs:

C = [value1 xdata(1) xdata(2)...value2 xdata(1) xdata(2)...;
       dim1 ydata(1) ydata(2)...  dim2 ydata(1) ydata(2)...]

That is,

C = [C(1) C(2)...C(I)...C(N)]

where N is the number of contour levels, and

C(i) = [ level(i) x(1) x(2)...x(  numel(i));
         numel(i) y(1) y(2)...y(  numel(i))];

For further information, see The Contouring Algorithm.

CreateFcn

string or function handle

Callback routine executed during object creation. This property defines a callback that executes when MATLAB creates an object. You must specify the callback during the creation of the object. For example,

area(y,'CreateFcn',@CallbackFcn)

where @CallbackFcn is a function handle that references the callback function.

MATLAB executes this routine after setting all other object properties. Setting this property on an existing object has no effect.

The handle of the object whose CreateFcn is being executed is accessible only through the root CallbackObject property, which you can query using gcbo.

See Function Handle Callbacks for information on how to use function handles to define the callback function.

DeleteFcn

string or function handle

Callback executed during object deletion. A callback that executes when this object is deleted (e.g., this might happen when you issue a delete command on the object, its parent axes, or the figure containing it). MATLAB executes the callback before destroying the object's properties so the callback routine can query these values.

The handle of the object whose DeleteFcn is being executed is accessible only through the root CallbackObject property, which can be queried using gcbo.

See Function Handle Callbacks for information on how to use function handles to define the callback function.

See the BeingDeleted property for related information.

DisplayName

string (default is empty string)

String used by legend for this contourgroup object. The legend function uses the string defined by the DisplayName property to label this contourgroup object in the legend.

If you specify string arguments with the legend function, DisplayName is set to this contourgroup object's corresponding string and that string is used for the legend.
If DisplayName is empty, legend creates a string of the form, ['data' n], where n is the number assigned to the object based on its location in the list of legend entries. However, legend does not set DisplayName to this string.
If you edit the string directly in an existing legend, DisplayName is set to the edited string.
If you specify a string for the DisplayName property and create the legend using the figure toolbar, then MATLAB uses the string defined by DisplayName.
To add programmatically a legend that uses the DisplayName string, call legend with the toggle or show option.

See Controlling Legends for more examples.

EraseMode

{normal} | none | xor | background

Erase mode. This property controls the technique MATLAB uses to draw and erase objects and their children. Alternative erase modes are useful for creating animated sequences, where control of the way individual objects are redrawn is necessary to improve performance and obtain the desired effect.

normal — Redraw the affected region of the display, performing the three-dimensional analysis necessary to ensure that all objects are rendered correctly. This mode produces the most accurate picture, but is the slowest. The other modes are faster, but do not perform a complete redraw and are therefore less accurate.
none — Do not erase objects when they are moved or destroyed. While the objects are still visible on the screen after erasing with EraseMode none, you cannot print these objects because MATLAB stores no information about their former locations.
xor — Draw and erase the object by performing an exclusive OR (XOR) with each pixel index of the screen behind it. Erasing the object does not damage the color of the objects behind it. However, the color of the erased object depends on the color of the screen behind it and it is correctly colored only when it is over the axes background color (or the figure background color if the axes Color property is set to none). That is, it isn't erased correctly if there are objects behind it.
background — Erase the graphics objects by redrawing them in the axes background color, (or the figure background color if the axes Color property is set to none). This damages other graphics objects that are behind the erased object, but the erased object is always properly colored.

Printing with Nonnormal Erase Modes

MATLAB always prints figures as if the EraseMode of all objects is normal. This means graphics objects created with EraseMode set to none, xor, or background can look different on screen than on paper. On screen, MATLAB can mathematically combine layers of colors (e.g., performing an XOR on a pixel color with that of the pixel behind it) and ignore three-dimensional sorting to obtain greater rendering speed. However, these techniques are not applied to the printed output.

Set the axes background color with the axes Color property. Set the figure background color with the figure Color property.

You can use the MATLAB getframe command or other screen capture applications to create an image of a figure containing nonnormal mode objects.

Fill

{off} | on

Color spaces between contour lines. By default, contour draws only the contour lines of the surface. If you set Fill to on, contour colors the regions in between the contour lines according to the Z-value of the region and changes the contour lines to black.

HandleVisibility

{on} | callback | off

Control access to object's handle by command-line users and GUIs. This property determines when an object's handle is visible in its parent's list of children. HandleVisibility is useful for preventing command-line users from accidentally accessing objects that you need to protect for some reason.

on — Handles are always visible when HandleVisibility is on.
callback — Setting HandleVisibility to callback causes handles to be visible from within callback routines or functions invoked by callback routines, but not from within functions invoked from the command line. This provides a means to protect GUIs from command-line users, while allowing callback routines to have access to object handles.
off — Setting HandleVisibility to off makes handles invisible at all times. This might be necessary when a callback invokes a function that might potentially damage the GUI (such as evaluating a user-typed string) and so temporarily hides its own handles during the execution of that function.

Functions Affected by Handle Visibility

When a handle is not visible in its parent's list of children, it cannot be returned by functions that obtain handles by searching the object hierarchy or querying handle properties. This includes get, findobj, gca, gcf, gco, newplot, cla, clf, and close.

Properties Affected by Handle Visibility

When a handle's visibility is restricted using callback or off, the object's handle does not appear in its parent's Children property, figures do not appear in the root's CurrentFigure property, objects do not appear in the root's CallbackObject property or in the figure's CurrentObject property, and axes do not appear in their parent's CurrentAxes property.

Overriding Handle Visibility

You can set the root ShowHiddenHandles property to on to make all handles visible regardless of their HandleVisibility settings (this does not affect the values of the HandleVisibility properties). See also findall.

Handle Validity

Handles that are hidden are still valid. If you know an object's handle, you can set and get its properties and pass it to any function that operates on handles.

Note If you change one data source property to a variable that contains data of a different dimension, you might cause the function to generate a warning and not render the graph until you have changed all data source properties to appropriate values.

HitTest

{on} | off

Selectable by mouse click. HitTest determines whether this object can become the current object (as returned by the gco command and the figure CurrentObject property) as a result of a mouse click on the objects that compose the area graph. If HitTest is off, clicking this object selects the object below it (which is usually the axes containing it).

HitTestArea

on | {off}

Select the object by clicking lines or area of extent. This property enables you to select plot objects in two ways:

Select by clicking lines or markers (default).
Select by clicking anywhere in the extent of the plot.

When HitTestArea is off, you must click th eobject's lines or markers (excluding the baseline, if any) to select the object. When HitTestArea is on, you can select this object by clicking anywhere within the extent of the plot (i.e., anywhere within a rectangle that encloses it).

Interruptible

{on} | off

Callback routine interruption mode. The Interruptible property controls whether an object's callback can be interrupted by callbacks invoked subsequently.

Only callbacks defined for the ButtonDownFcn property are affected by the Interruptible property. MATLAB checks for events that can interrupt a callback only when it encounters a drawnow, figure, getframe, or pause command in the routine. See the BusyAction property for related information.

Setting Interruptible to on allows any graphics object's callback to interrupt callback routines originating from a bar property. Note that MATLAB does not save the state of variables or the display (e.g., the handle returned by the gca or gcf command) when an interruption occurs.

LabelSpacing

distance in points (default = 144)

Spacing between labels on each contour line. When you display contour line labels using either the ShowText property or the clabel command, the labels are spaced 144 points (2 inches) apart on each line. You can specify the spacing by setting the LabelSpacing property to a value in points. If the length of an individual contour line is less than the specified value, MATLAB displays only one contour label on that line.

LevelList

vector of ZData-values

Values at which contour lines are drawn. When the LevelListMode property is auto, the contour function automatically chooses contour values that span the range of values in ZData (the input argument Z). You can set this property to the values at which you want contour lines drawn.

To specify the contour interval (space between contour lines) use the LevelStep property.

LevelListMode

{auto} | manual

User-specified or autogenerated LevelList values. By default, the contour function automatically generates the values at which contours are drawn. If you set this property to manual, contour does not change the values in LevelList as you change the values of ZData.

LevelStep

scalar

Spacing of contour lines. The contour function draws contour lines at regular intervals determined by the value of LevelStep. When the LevelStepMode property is set to auto, contour determines the contour interval automatically based on the ZData.

LevelStepMode

{auto} | manual

User-specified or autogenerated LevelStep values. By default, the contour function automatically determines a value for the LevelStep property. If you set this property to manual, contour does not change the value of LevelStep as you change the values of ZData.

LineColor

{auto} | ColorSpec | none

Color of the contour lines. This property determines how MATLAB colors the contour lines.

auto— Each contour line is a single color determined by its contour value, the figure colormap, and the color axis (caxis).
ColorSpec — A three-element RGB vector or one of the MATLAB predefined names, specifying a single color for edges. The default edge color is black. See ColorSpec for more information on specifying color.
none — No contour lines are drawn.

LineStyle

{-} | --| : |-. | none

Line style. This property specifies the line style of the object. Available line styles are shown in the following table.

Specifier String	Line Style
`-`	Solid line (default)
`--`	Dashed line
`:`	Dotted line
`-.`	Dash-dot line
`none`	No line

LineWidth

scalar

The width of linear objects and edges of filled areas. Specify this value in points (1 point = ¹/₇₂ inch). The default LineWidth is 0.5 points.

Parent

handle of parent axes, hggroup, or hgtransform

Parent of this object. This property contains the handle of the object's parent. The parent is normally the axes, hggroup, or hgtransform object that contains the object.

See Objects That Can Contain Other Objects for more information on parenting graphics objects.

Selected

on | {off}

Is object selected? When you set this property to on, MATLAB displays selection "handles" at the corners and midpoints if the SelectionHighlight property is also on (the default). You can, for example, define the ButtonDownFcn callback to set this property to on, thereby indicating that this particular object is selected. This property is also set to on when an object is manually selected in plot edit mode.

SelectionHighlight

{on} | off

Objects are highlighted when selected. When the Selected property is on, MATLAB indicates the selected state by drawing four edge handles and four corner handles. When SelectionHighlight is off, MATLAB does not draw the handles except when in plot edit mode and objects are selected manually.

ShowText

on | {off}

Display labels on contour lines. When you set this property to on, MATLAB displays text labels on each contour line indicating the contour value. See also LevelList, clabel, and the example Contour Plot of a Function.

Tag

string

User-specified object label. The Tag property provides a means to identify graphics objects with a user-specified label. This is particularly useful when you are constructing interactive graphics programs that would otherwise need to define object handles as global variables or pass them as arguments between callbacks. You can define Tag as any string.

For example, you might create an areaseries object and set the Tag property.

t = area(Y,'Tag','area1')

When you want to access objects of a given type, you can use findobj to find the object's handle. The following statement changes the FaceColor property of the object whose Tag is area1.

set(findobj('Tag','area1'),'FaceColor','red')

TextList

vector of contour values

Contour values to label. This property contains the contour values where text labels are placed. By default, these values are the same as those contained in the LevelList property, which define where the contour lines are drawn. Note that there must be an equivalent contour line to display a text label.

For example, the following statements create and label a contour plot:

[c,h]=contour(peaks);
clabel(c,h)

You can get the LevelList property to see the contour line values:

get(h,'LevelList')

Suppose you want to view the contour value 4.375 instead of the value of 4 that the contour function used. To do this, you need to set both the LevelList and TextList properties:

set(h,'LevelList',[-6 -4 -2 0 2 4.375 6 8],...
	'TextList',[-6 -4 -2 0 2 4.375 6 8])

See the example Contour Plot of a Function for additional information.

TextListMode

{auto} | manual

User-specified or auto TextList values. When this property is set to auto, MATLAB sets the TextList property equal to the values of the LevelList property (i.e., a text label for each contour line). When this property is set to manual, MATLAB does not set the values of the TextList property. Note that specifying values for the TextList property causes the TextListMode property to be set to manual.

TextStep

scalar

Determines which contour line have numeric labels. The contour function labels contour lines at regular intervals which are determined by the value of the TextStep property. When the TextStepMode property is set to auto, contour labels every contour line when the ShowText property is on. See Contour Plot of a Function for an example that uses the TextStep property.

TextStepMode

{auto} | manual

User-specified or autogenerated TextStep values. By default, the contour function automatically determines a value for the TextStep property. If you set this property to manual, contour does not change the value of TextStep as you change the values of ZData.

Type

string (read only)

Type of graphics object. This property contains a string that identifies the class of graphics object. For contourgroup objects, Type is 'hggroup'. This statement finds all the hggroup objects in the current axes.

t = findobj(gca,'Type','hggroup');

UIContextMenu

handle of a uicontextmenu object

Associate a context menu with this object. Assign this property the handle of a uicontextmenu object created in the object's parent figure. Use the uicontextmenu function to create the context menu. MATLAB displays the context menu whenever you right-click over the object.

UserData

array

User-specified data. This property can be any data you want to associate with this object (including cell arrays and structures). The object does not set values for this property, but you can access it using the set and get functions.

Visible

{on} | off

Visibility of this object and its children. By default, a new object's visibility is on. This means all children of the object are visible unless the child object's Visible property is set to off. Setting an object's Visible property to off prevents the object from being displayed. However, the object still exists and you can set and query its properties.

XData

vector or matrix

The x-axis values for a graph. The x-axis values for graphs are specified by the X input argument. If XData is a vector, length(XData) must equal length(YData) and must be monotonic. If XData is a matrix, size(XData) must equal size(YData) and each column must be monotonic.

You can use XData to define meaningful coordinates for an underlying surface whose topography is being mapped. See Changing the Offset of a Contour for more information.

XDataMode

{auto} | manual

Use automatic or user-specified x-axis values. If you specify XData (by setting the XData property or specifying the x input argument), MATLAB sets this property to manual and uses the specified values to label the x-axis.

If you set XDataMode to auto after having specified XData, MATLAB resets the x-axis ticks to 1:size(YData,1) or to the column indices of the ZData, overwriting any previous values for XData.

XDataSource

string (MATLAB variable)

Link XData to MATLAB variable. Set this property to a MATLAB variable that is evaluated in the base workspace to generate the XData.

MATLAB reevaluates this property only when you set it. Therefore, a change to workspace variables appearing in an expression does not change XData.

You can use the refreshdata function to force an update of the object's data. refreshdata also enables you to specify that the data source variable be evaluated in the workspace of a function from which you call refreshdata.

See the refreshdata reference page for more information.

YData

scalar, vector, or matrix

Y-axis limits. This property determines the y-axis limits used in the contour plot. If you do not specify a Y argument, the contour function calculates y-axis limits based on the size of the input argument Z.

YData can be either a matrix equal in size to ZData or a vector equal in length to the number of columns in ZData.

Use YData to define meaningful coordinates for the underlying surface whose topography is being mapped. See Changing the Offset of a Contour for more information.

YDataMode

{auto} | manual

Use automatic or user-specified y-axis values. In auto mode (the default) the contour function automatically determines the y-axis limits. If you set this property to manual, specify a value for YData, or specify a Y argument, then contour sets this property to manual and does not change the axis limits.

YDataSource

string (MATLAB variable)

Link YData to MATLAB variable. Set this property to a MATLAB variable that is evaluated in the base workspace to generate the YData.

MATLAB reevaluates this property only when you set it. Therefore, a change to workspace variables appearing in an expression does not change YData.

See the refreshdata reference page for more information.

ZData

matrix

Contour data. This property contains the data from which the contour lines are generated (specified as the input argument Z). ZData must be at least a 2-by-2 matrix. The number of contour levels and the values of the contour levels are chosen automatically based on the minimum and maximum values of ZData. The limits of the x- and y-axis are [1:n] and [1:m], where [m,n] = size(ZData).

ZDataSource