Canvas

Instances of this class provide a surface for drawing arbitrary graphics. <dl> <dt>Styles:</dt> <dd>(none)</dd> <dt>Events:</dt> <dd>(none)</dd> </dl> This class may be subclassed by custom control implementors who are building controls that are not constructed from aggregates of other controls. That is, they are either painted using SWT graphics calls or are handled by native methods.

@see Composite @see <a href="http://www.eclipse.org/swt/snippets/#canvas">Canvas snippets</a> @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a> @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>

class Canvas : Composite {

Caret caret;

IME ime;

this(Composite parent, int style);

void drawBackground(GC gc, int x, int y, int width, int height);

Caret getCaret();

IME getIME();

void scroll(int destX, int destY, int x, int y, int width, int height, bool all);

void setCaret(Caret caret);

void setIME(IME ime);

}

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. 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 bitwise OR'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.

Members

Functions

drawBackground void drawBackground(GC gc, int x, int y, int width, int height): Fills the interior of the rectangle specified by the arguments, with the receiver's background.
getCaret Caret getCaret(): Returns the caret. The caret for the control is automatically hidden and shown when the control is painted or resized, when focus is gained or lost and when an the control is scrolled. To avoid drawing on top of the caret, the programmer must hide and show the caret when drawing in the window any other time.
getIME IME getIME(): Returns the IME.
scroll void scroll(int destX, int destY, int x, int y, int width, int height, bool all): Scrolls a rectangular area of the receiver by first copying the source area to the destination and then causing the area of the source which is not covered by the destination to be repainted. Children that intersect the rectangle are optionally moved during the operation. In addition, outstanding paint events are flushed before the source area is copied to ensure that the contents of the canvas are drawn correctly.
setCaret void setCaret(Caret caret): Sets the receiver's caret. The caret for the control is automatically hidden and shown when the control is painted or resized, when focus is gained or lost and when an the control is scrolled. To avoid drawing on top of the caret, the programmer must hide and show the caret when drawing in the window any other time. @param caret the new caret for the receiver, may be null
setIME void setIME(IME ime): Sets the receiver's IME.

Inherited Members

From Composite

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. 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.
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 lay out (that is, set the size and location of) the receiver's children. If the receiver does not have a layout, do nothing. This is equivalent to calling <code>layout(true)</code>. 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.
layout void layout(bool changed): If the receiver has a layout, asks the layout to lay out (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. 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>). 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.
layout void layout(bool changed, bool all): If the receiver has a layout, asks the layout to lay out (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 not 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>). 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.
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. 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.
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.