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Surface Properties

Modifying Properties

You can set and query graphics object properties in two ways:

To change the default values of properties, see Setting Default Property Values.

See Core Objects for general information about this type of object.

Surface Property Descriptions

This section lists property names along with the types of values each accepts. Curly braces { } enclose default values.

AlphaData                    m-by-n matrix of double or uint8

The transparency data. A matrix of non-NaN values specifying the transparency of each face or vertex of the object. The AlphaData can be of class double or uint8.

MATLAB determines the transparency in one of three ways:

AlphaDataMapping             none | direct | {scaled}

Transparency mapping method. This property determines how MATLAB interprets indexed alpha data. This property can be any of the following:

AmbientStrength              scalar >= 0 and <= 1

Strength of ambient light. This property sets the strength of the ambient light, which is a nondirectional light source that illuminates the entire scene. You must have at least one visible light object in the axes for the ambient light to be visible. The axes AmbientLightColor property sets the color of the ambient light, which is therefore the same on all objects in the axes.

You can also set the strength of the diffuse and specular contribution of light objects. See the surface DiffuseStrength and SpecularStrength properties.

BackFaceLighting             unlit | lit | reverselit

Face lighting control. This property determines how faces are lit when their vertex normals point away from the camera.

This property is useful for discriminating between the internal and external surfaces of an object. See Back Face Lighting for an example.

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 may not need to perform actions on objects that 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 callback routines. If there is a callback routine executing, callback routines 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

ButtonDownFcn                string or function handle

Button press callback routine. A callback routine that executes whenever you press a mouse button while the pointer is over the surface object.

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

Set this property to a function handle that references the callback. You can also use a string that is a valid MATLAB expression or the name of an M-file. The expressions execute in the MATLAB workspace.

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

CData                        matrix

Vertex colors. A matrix containing values that specify the color at every point in ZData. If you set the FaceColor property to texturemap, CData does not need to be the same size as ZData. In this case, MATLAB maps CData to conform to the surface defined by ZData.

You can specify color as indexed values or true color. Indexed color data specifies a single value for each vertex. These values are either scaled to map linearly into the current colormap (see caxis) or interpreted directly as indices into the colormap, depending on the setting of the CDataMapping property.

True color defines an RGB value for each vertex. If the coordinate data (XData, for example) are contained in m-by-n matrices, then CData must be an m-by-n-3 array. The first page contains the red components, the second the green components, and the third the blue components of the colors.

CDataMapping                 {scaled} | direct

Direct or scaled color mapping. This property determines how MATLAB interprets indexed color data used to color the surface. (If you use true color specification for CData, this property has no effect.)

Children                     matrix of handles

Always the empty matrix; surface objects have no children.

Clipping                     {on} | off

Clipping to axes rectangle. When Clipping is on, MATLAB does not display any portion of the surface that is outside the axes rectangle.

CreateFcn                    string or function handle

Callback routine executed during object creation. This property defines a callback routine that executes when MATLAB creates a surface object. You must define this property as a default value for surfaces or set the CreateFcn property during object creation.

For example, the following statement creates a surface (assuming x, y, z, and c are defined), and executes the function referenced by the function handle @myCreateFcn.

MATLAB executes this routine after setting all surface properties. Setting this property on an existing surface 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

Delete surface callback routine. A callback routine that executes when you delete the surface object (e.g., when you issue a delete command or clear the axes or figure). MATLAB executes the routine before destroying the object's properties so these values are available to the callback routine.

The handle of the object whose DeleteFcn 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.

DiffuseStrength              scalar >= 0 and <= 1

Intensity of diffuse light. This property sets the intensity of the diffuse component of the light falling on the surface. Diffuse light comes from light objects in the axes.

You can also set the intensity of the ambient and specular components of the light on the surface object. See the AmbientStrength and SpecularStrength properties.

EdgeAlpha                    {scalar = 1} | flat | interp

Transparency of the surface edges. This property can be any of the following:

Note that you must specify AlphaData as a matrix equal in size to ZData to use flat or interp EdgeAlpha.

EdgeColor                    {ColorSpec} | none | flat | interp

Color of the surface edge. This property determines how MATLAB colors the edges of the individual faces that make up the surface:

EdgeLighting                 {none} | flat | gouraud | phong

Algorithm used for lighting calculations. This property selects the algorithm used to calculate the effect of light objects on surface edges. Choices are

EraseMode                    {normal} | none | xor | background

Erase mode. This property controls the technique MATLAB uses to draw and erase surface objects. 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.

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 may mathematically combine layers of colors (e.g., performing an XOR of 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.

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

FaceAlpha                    {scalar = 1} | flat | interp | texturemap

Transparency of the surface faces. This property can be any of the following:

Note that you must specify AlphaData as a matrix equal in size to ZData to use flat or interp FaceAlpha.

FaceColor                    ColorSpec | none | {flat} | interp

Color of the surface face. This property can be any of the following:

FaceLighting                 {none} | flat | gouraud | phong

Algorithm used for lighting calculations. This property selects the algorithm used to calculate the effect of light objects on the surface. Choices are

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. This property is useful for preventing command-line users from accidentally drawing into or deleting a figure that contains only user interface devices (such as a dialog box).

Handles are always visible when HandleVisibility is on.

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 complete access to object handles.

Setting HandleVisibility to off makes handles invisible at all times. This might be necessary when a callback routine invokes a function that could potentially damage the GUI (such as evaluating a user-typed string), and so temporarily hides its own handles during the execution of that function.

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.

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.

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).

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.

HitTest                      {on} | off

Selectable by mouse click. HitTest determines if the surface 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 surface. If HitTest is off, clicking on the surface selects the object below it (which may be the axes containing it).

Interruptible                {on} | off

Callback routine interruption mode. The Interruptible property controls whether a surface callback routine can be interrupted by subsequently invoked callback routines. Only callback routines defined for the ButtonDownFcn are affected by the Interruptible property. MATLAB checks for events that can interrupt a callback routine only when it encounters a drawnow, figure, getframe, or pause command in the routine. See the BusyAction property for related information.

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

Edge line type. This property determines the line style used to draw surface edges. The available line styles are shown in this table.

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

LineWidth                    scalar

Edge line width. The width of the lines in points used to draw surface edges. The default width is 0.5 points (1 point = 1/72 inch).

Marker                       marker symbol (see table)

Marker symbol. The Marker property specifies symbols that are displayed at vertices. You can set values for the Marker property independently from the LineStyle property.

You can specify these markers.

Marker Specifier
Description
+
Plus sign
o
Circle
*
Asterisk
.
Point
x
Cross
s
Square
d
Diamond
^
Upward-pointing triangle
v
Downward-pointing triangle
>
Right-pointing triangle
<
Left-pointing triangle
p
Five-pointed star (pentagram)
h
Six-pointed star (hexagram)
none
No marker (default)

MarkerEdgeColor              none | {auto} | flat | ColorSpec

Marker edge color. The color of the marker or the edge color for filled markers (circle, square, diamond, pentagram, hexagram, and the four triangles).

MarkerFaceColor               {none} | auto | flat | ColorSpec

Marker face color. The fill color for markers that are closed shapes (circle, square, diamond, pentagram, hexagram, and the four triangles).

MarkerSize                   size in points

Marker size. A scalar specifying the marker size, in points. The default value for MarkerSize is 6 points (1 point = 1/72 inch). Note that MATLAB draws the point marker at 1/3 the specified marker size.

MeshStyle                    {both} | row | column

Row and column lines. This property specifies whether to draw all edge lines or just row or column edge lines.

NormalMode                   {auto} | manual

MATLAB generated or user-specified normal vectors. When this property is auto, MATLAB calculates vertex normals based on the coordinate data. If you specify your own vertex normals, MATLAB sets this property to manual and does not generate its own data. See also the VertexNormals property.

Parent                       handle of axes, hggroup, or hgtransform

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

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

Selected                     on | {off}

Is object selected? When this property is on, MATLAB displays a dashed bounding box around the surface if the SelectionHighlight property is also on. You can, for example, define the ButtonDownFcn to set this property, allowing users to select the object with the mouse.

SelectionHighlight           {on} | off

Objects are highlighted when selected. When the Selected property is on, MATLAB indicates the selected state by drawing a dashed bounding box around the surface. When SelectionHighlight is off, MATLAB does not draw the handles.

SpecularColorReflectance     scalar in the range 0 to 1

Color of specularly reflected light. When this property is 0, the color of the specularly reflected light depends on both the color of the object from which it reflects and the color of the light source. When set to 1, the color of the specularly reflected light depends only on the color or the light source (i.e., the light object Color property). The proportions vary linearly for values in between.

SpecularExponent             scalar >= 1

Harshness of specular reflection. This property controls the size of the specular spot. Most materials have exponents in the range of 5 to 20.

SpecularStrength             scalar >= 0 and <= 1

Intensity of specular light. This property sets the intensity of the specular component of the light falling on the surface. Specular light comes from light objects in the axes.

You can also set the intensity of the ambient and diffuse components of the light on the surface object. See the AmbientStrength and DiffuseStrength properties. Also see the material 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 callback routines. You can define Tag as any string.

Type                         string (read only)

Class of the graphics object. The class of the graphics object. For surface objects, Type is always the string 'surface'.

UIContextMenu                handle of a uicontextmenu object

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

UserData                     matrix

User-specified data. Any matrix you want to associate with the surface object. MATLAB does not use this data, but you can access it using the set and get commands.

VertexNormals                vector or matrix

Surface normal vectors. This property contains the vertex normals for the surface. MATLAB generates this data to perform lighting calculations. You can supply your own vertex normal data, even if it does not match the coordinate data. This can be useful to produce interesting lighting effects.

Visible                      {on} | off

Surface object visibility. By default, all surfaces are visible. When set to off, the surface is not visible, but still exists, and you can query and set its properties.

XData                        vector or matrix

X-coordinates. The x-position of the surface points. If you specify a row vector, surface replicates the row internally until it has the same number of columns as ZData.

YData                        vector or matrix

Y-coordinates. The y-position of the surface points. If you specify a row vector, surface replicates the row internally until it has the same number of rows as ZData.

ZData                        matrix

Z-coordinates. The z-position of the surface points. See the Description section for more information.


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