MATLAB Function Reference

Line Properties

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

• The Property Editor is an interactive tool that enables you to see and change object property values.
• The set and get commands enable you to set and query the values of properties

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

Line Property Descriptions

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

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, subsequently invoked callback routes 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.

Button press callback routine. A callback routine that executes whenever you press a mouse button while the pointer is over the line object. Define this routine as a string that is a valid MATLAB expression or the name of an M-file. The expression executes in the MATLAB workspace.

The empty matrix; line objects have no children.

Clipping mode. MATLAB clips lines to the axes plot box by default. If you set Clipping to off, lines display outside the axes plot box. This can occur if you create a line, set hold to on, freeze axis scaling (axis manual), and then create a longer line.

Line color. A three-element RGB vector or one of MATLAB's predefined names, specifying the line color. See the ColorSpec reference page for more information on specifying color.

Callback routine executed during object creation. This property defines a callback routine that executes when MATLAB creates a line object. You must define this property as a default value for lines. For example, the statement,

set(0,'DefaultLineCreateFcn','set(gca,''LineStyleOrder'',''-.|--'')')

defines a default value on the root level that sets the axes LineStyleOrder whenever you create a line object. MATLAB executes this routine after setting all line properties. Setting this property on an existing line 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.

Delete line callback routine. A callback routine that executes when you delete the line object (e.g., when you issue a delete command or clear the axes or figure). MATLAB executes the routine before deleting 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.

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

• normal (the default) -- 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 the line when it is moved or destroyed. While the object is still visible on the screen after erasing with EraseMode none, you cannot print it because MATLAB stores no information about its former location.
• xor - Draw and erase the line by performing an exclusive OR (XOR) with the color of the screen beneath it. This mode does not damage the color of the objects beneath the line. However, the line's color depends on the color of whatever is beneath it on the display.
• background - Erase the line by drawing it in the axes' background Color, or the figure background Color if the axes Color is set to none. This damages objects that are behind the erased line, but lines are always properly colored.

Printing with Non-normal 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 may mathematically combine layers of colors (e.g., XORing 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 non-normal mode objects.

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

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 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 may be necessary when a callback routine invokes a function that might potentially damage the GUI (such as evaling 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 propertes. 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.

Callback routine interruption mode. The Interruptible property controls whether a line 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.

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

Symbol	Line Style
-	solid line (default)
--	dashed line
:	dotted line
-.	dash-dot line
none	no line

You can use LineStyle none when you want to place a marker at each point but do not want the points connected with a line (see the Marker property).

The width of the line object. Specify this value in points (1 point = ¹/₇₂ inch). The default LineWidth is 0.5 points.

Marker symbol. The Marker property specifies marks that display at data points. You can set values for the Marker property independently from the LineStyle property. Supported markers include those shown in the table.

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)

Marker edge color. The color of the marker or the edge color for filled markers (circle, square, diamond, pentagram, hexagram, and the four triangles). ColorSpec defines the color to use. none specifies no color, which makes nonfilled markers invisible. auto sets MarkerEdgeColor to the same color as the line's Color property.

Marker face color. The fill color for markers that are closed shapes (circle, square, diamond, pentagram, hexagram, and the four triangles). ColorSpec defines the color to use. none makes the interior of the marker transparent, allowing the background to show through. auto sets the fill color to the axes color, or the figure color, if the axes Color property is set to none (which is the factory default for axes).

Marker size. A scalar specifying the size of the marker, in points. The default value for MarkerSize is six points (1 point = 1/72 inch). Note that MATLAB draws the point marker (specified by the '.' symbol) at one-third the specified size.

Line's parent. The handle of the line object's parent axes. You can move a line object to another axes by changing this property to the new axes handle.

Is object selected. When this property is on. MATLAB displays selection handles 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.

Objects highlight when selected. When the Selected property is on, MATLAB indicates the selected state by drawing handles at each vertex. When SelectionHighlight is off, MATLAB does not draw the handles.

User-specified object label. The Tag property provides a means to identify graphics objects with a user-specified label. This is particularly useful when 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.

Class of graphics object. For line objects, Type is always the string 'line'.

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

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

Line visibility. By default, all lines are visible. When set to off, the line is not visible, but still exists and you can get and set its properties.

X-coordinates. A vector of x-coordinates defining the line. YData and ZData must have the same number of rows. (See Examples).

Y-coordinates. A vector of y-coordinates defining the line. XData and ZData must have the same number of rows.

Z-coordinates. A vector of z-coordinates defining the line. XData and YData must have the same number of rows.

See Also

axes,newplot, plot, plot3

line

LineSpec