Composite

Instances of this class are controls which are capable of containing other controls. <dl> <dt><b>Styles:</b></dt> <dd>NO_BACKGROUND, NO_FOCUS, NO_MERGE_PAINTS, NO_REDRAW_RESIZE, NO_RADIO_GROUP, EMBEDDED, DOUBLE_BUFFERED</dd> <dt><b>Events:</b></dt> <dd>(none)</dd> </dl> <p> Note: The <code>NO_BACKGROUND</code>, <code>NO_FOCUS</code>, <code>NO_MERGE_PAINTS</code>, and <code>NO_REDRAW_RESIZE</code> styles are intended for use with <code>Canvas</code>. They can be used with <code>Composite</code> if you are drawing your own, but their behavior is undefined if they are used with subclasses of <code>Composite</code> other than <code>Canvas</code>. </p><p> Note: The <code>CENTER</code> style, although undefined for composites, has the same value as <code>EMBEDDED</code> (which is used to embed widgets from other widget toolkits into SWT). On some operating systems (GTK, Motif), this may cause the children of this composite to be obscured. The <code>EMBEDDED</code> style is for use by other widget toolkits and should normally never be used. </p><p> This class may be subclassed by custom control implementors who are building controls that are constructed from aggregates of other controls. </p>

@see Canvas @see <a href="http://www.eclipse.org/swt/snippets/#composite">Composite snippets</a> @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>

Constructors

this
this(Composite parent, int style)

Constructs a new instance of this class given its parent and a style value describing its behavior and appearance. <p> The style value is either one of the style constants defined in class <code>SWT</code> which is applicable to instances of this class, or must be built by <em>bitwise OR</em>'ing together (that is, using the <code>int</code> "|" operator) two or more of those <code>SWT</code> style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses. </p>

Members

Functions

changed
void changed(Control[] changed)

Clears any data that has been cached by a Layout for all widgets that are in the parent hierarchy of the changed control up to and including the receiver. If an ancestor does not have a layout, it is skipped.

getBackgroundMode
int getBackgroundMode()

Returns the receiver's background drawing mode. This will be one of the following constants defined in class <code>SWT</code>: <code>INHERIT_NONE</code>, <code>INHERIT_DEFAULT</code>, <code>INHERTIT_FORCE</code>.

getChildren
Control[] getChildren()

Returns a (possibly empty) array containing the receiver's children. Children are returned in the order that they are drawn. The topmost control appears at the beginning of the array. Subsequent controls draw beneath this control and appear later in the array. <p> Note: This is not the actual structure used by the receiver to maintain its list of children, so modifying the array will not affect the receiver. </p>

getLayout
Layout getLayout()

Returns layout which is associated with the receiver, or null if one has not been set.

getLayoutDeferred
bool getLayoutDeferred()

Returns <code>true</code> if the receiver has deferred the performing of layout, and <code>false</code> otherwise.

getTabList
Control[] getTabList()

Gets the (possibly empty) tabbing order for the control.

isLayoutDeferred
bool isLayoutDeferred()

Returns <code>true</code> if the receiver or any ancestor up to and including the receiver's nearest ancestor shell has deferred the performing of layouts. Otherwise, <code>false</code> is returned.

layout
void layout()

If the receiver has a layout, asks the layout to <em>lay out</em> (that is, set the size and location of) the receiver's children. If the receiver does not have a layout, do nothing. <p> This is equivalent to calling <code>layout(true)</code>. </p> <p> Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint. </p>

layout
void layout(bool changed)

If the receiver has a layout, asks the layout to <em>lay out</em> (that is, set the size and location of) the receiver's children. If the argument is <code>true</code> the layout must not rely on any information it has cached about the immediate children. If it is <code>false</code> the layout may (potentially) optimize the work it is doing by assuming that none of the receiver's children has changed state since the last layout. If the receiver does not have a layout, do nothing. <p> If a child is resized as a result of a call to layout, the resize event will invoke the layout of the child. The layout will cascade down through all child widgets in the receiver's widget tree until a child is encountered that does not resize. Note that a layout due to a resize will not flush any cached information (same as <code>layout(false)</code>). </p> <p> Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint. </p>

layout
void layout(bool changed, bool all)

If the receiver has a layout, asks the layout to <em>lay out</em> (that is, set the size and location of) the receiver's children. If the changed argument is <code>true</code> the layout must not rely on any information it has cached about its children. If it is <code>false</code> the layout may (potentially) optimize the work it is doing by assuming that none of the receiver's children has changed state since the last layout. If the all argument is <code>true</code> the layout will cascade down through all child widgets in the receiver's widget tree, regardless of whether the child has changed size. The changed argument is applied to all layouts. If the all argument is <code>false</code>, the layout will <em>not</em> cascade down through all child widgets in the receiver's widget tree. However, if a child is resized as a result of a call to layout, the resize event will invoke the layout of the child. Note that a layout due to a resize will not flush any cached information (same as <code>layout(false)</code>). </p> <p> Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint. </p>

layout
void layout(Control[] changed)

Forces a lay out (that is, sets the size and location) of all widgets that are in the parent hierarchy of the changed control up to and including the receiver. The layouts in the hierarchy must not rely on any information cached about the changed control or any of its ancestors. The layout may (potentially) optimize the work it is doing by assuming that none of the peers of the changed control have changed state since the last layout. If an ancestor does not have a layout, skip it. <p> Note: Layout is different from painting. If a child is moved or resized such that an area in the parent is exposed, then the parent will paint. If no child is affected, the parent will not paint. </p>

setBackgroundMode
void setBackgroundMode(int mode)

Sets the background drawing mode to the argument which should be one of the following constants defined in class <code>SWT</code>: <code>INHERIT_NONE</code>, <code>INHERIT_DEFAULT</code>, <code>INHERIT_FORCE</code>.

setLayout
void setLayout(Layout layout)

Sets the layout which is associated with the receiver to be the argument which may be null.

setLayoutDeferred
void setLayoutDeferred(bool defer)

If the argument is <code>true</code>, causes subsequent layout operations in the receiver or any of its children to be ignored. No layout of any kind can occur in the receiver or any of its children until the flag is set to false. Layout operations that occurred while the flag was <code>true</code> are remembered and when the flag is set to <code>false</code>, the layout operations are performed in an optimized manner. Nested calls to this method are stacked.

setTabList
void setTabList(Control[] tabList)

Sets the tabbing order for the specified controls to match the order that they occur in the argument list.

Inherited Members

From Scrollable

computeTrim
Rectangle computeTrim(int x, int y, int width, int height)

Given a desired <em>client area</em> for the receiver (as described by the arguments), returns the bounding rectangle which would be required to produce that client area. <p> In other words, it returns a rectangle such that, if the receiver's bounds were set to that rectangle, the area of the receiver which is capable of displaying data (that is, not covered by the "trimmings") would be the rectangle described by the arguments (relative to the receiver's parent). </p>

getClientArea
Rectangle getClientArea()

Returns a rectangle which describes the area of the receiver which is capable of displaying data (that is, not covered by the "trimmings").

getHorizontalBar
ScrollBar getHorizontalBar()

Returns the receiver's horizontal scroll bar if it has one, and null if it does not.

getVerticalBar
ScrollBar getVerticalBar()

Returns the receiver's vertical scroll bar if it has one, and null if it does not.

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