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org.eclipse.swt.widgets
Class Canvas
java.lang.Object
org.eclipse.swt.widgets.Widget
org.eclipse.swt.widgets.Control
org.eclipse.swt.widgets.Scrollable
org.eclipse.swt.widgets.Composite
org.eclipse.swt.widgets.Canvas
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All Implemented Interfaces:
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Drawable
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Direct Known Subclasses:
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AbstractHyperlink,
AnimatedProgress,
CLabel,
Decorations,
ExpandableComposite,
FormText,
GLCanvas,
StyledText,
TableCursor
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public class Canvas
- extends
Composite
Instances of this class provide a surface for drawing
arbitrary graphics.
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Styles:
- (none)
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Events:
- (none)
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.
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See Also:
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Composite,
Canvas snippets,
SWT Example: ControlExample,
Sample code and further information
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Fields inherited from class org.eclipse.swt.widgets.
Control
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handle
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Constructor Summary
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Canvas
(
Composite parent,
int style)
Constructs a new instance of this class given its parent
and a style value describing its behavior and appearance. |
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Method Summary
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void
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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. |
Caret
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getCaret
()
Returns the caret. |
IME
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getIME
()
Returns the IME. |
void
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scroll
(int destX,
int destY,
int x,
int y,
int width,
int height,
boolean 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. |
void
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setCaret
(
Caret caret)
Sets the receiver's caret. |
void
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setFont
(
Font font)
Sets the font that the receiver will use to paint textual information
to the font specified by the argument, or to the default font for that
kind of control if the argument is null. |
void
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setIME
(
IME ime)
Sets the receiver's IME. |
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Methods inherited from class org.eclipse.swt.widgets.
Composite
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changed,
checkSubclass,
computeSize,
getBackgroundMode,
getChildren,
getLayout,
getLayoutDeferred,
getTabList,
isLayoutDeferred,
layout,
layout,
layout,
layout,
setBackgroundMode,
setFocus,
setLayout,
setLayoutDeferred,
setTabList
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Methods inherited from class org.eclipse.swt.widgets.
Control
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addControlListener,
addDragDetectListener,
addFocusListener,
addHelpListener,
addKeyListener,
addMenuDetectListener,
addMouseListener,
addMouseMoveListener,
addMouseTrackListener,
addMouseWheelListener,
addPaintListener,
addTraverseListener,
computeSize,
dragDetect,
dragDetect,
forceFocus,
getAccessible,
getBackground,
getBackgroundImage,
getBorderWidth,
getBounds,
getCursor,
getDragDetect,
getEnabled,
getFont,
getForeground,
getLayoutData,
getLocation,
getMenu,
getMonitor,
getParent,
getRegion,
getShell,
getSize,
getToolTipText,
getVisible,
internal_dispose_GC,
internal_new_GC,
isEnabled,
isFocusControl,
isReparentable,
isVisible,
moveAbove,
moveBelow,
pack,
pack,
print,
redraw,
redraw,
removeControlListener,
removeDragDetectListener,
removeFocusListener,
removeHelpListener,
removeKeyListener,
removeMenuDetectListener,
removeMouseListener,
removeMouseMoveListener,
removeMouseTrackListener,
removeMouseWheelListener,
removePaintListener,
removeTraverseListener,
setBackground,
setBackgroundImage,
setBounds,
setBounds,
setCapture,
setCursor,
setDragDetect,
setEnabled,
setForeground,
setLayoutData,
setLocation,
setLocation,
setMenu,
setParent,
setRedraw,
setRegion,
setSize,
setSize,
setToolTipText,
setVisible,
toControl,
toControl,
toDisplay,
toDisplay,
traverse,
update
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Methods inherited from class org.eclipse.swt.widgets.
Widget
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addDisposeListener,
addListener,
checkWidget,
dispose,
getData,
getData,
getDisplay,
getListeners,
getStyle,
isDisposed,
isListening,
notifyListeners,
removeDisposeListener,
removeListener,
removeListener,
setData,
setData,
toString
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Canvas
public Canvas(
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 SWT which is applicable to instances of this
class, or must be built by bitwise OR'ing together
(that is, using the int "|" operator) two or more
of those SWT style constants. The class description
lists the style constants that are applicable to the class.
Style bits are also inherited from superclasses.
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Parameters:
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parent - a composite control which will be the parent of the new instance (cannot be null) -
style - the style of control to construct
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the parent is null
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SWTException
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- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
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See Also:
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SWT,
Widget.checkSubclass(),
Widget.getStyle()
drawBackground
public 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.
-
-
Parameters:
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gc - the gc where the rectangle is to be filled -
x - the x coordinate of the rectangle to be filled -
y - the y coordinate of the rectangle to be filled -
width - the width of the rectangle to be filled -
height - the height of the rectangle to be filled
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Throws:
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IllegalArgumentException
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- ERROR_NULL_ARGUMENT - if the gc is null
- ERROR_INVALID_ARGUMENT - if the gc has been disposed
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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Since:
- 3.2
getCaret
public
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.
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Returns:
- the caret for the receiver, may be null
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
getIME
public
IME getIME()
- Returns the IME.
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Returns:
- the IME
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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Since:
- 3.4
scroll
public void scroll(int destX,
int destY,
int x,
int y,
int width,
int height,
boolean 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.
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Parameters:
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destX - the x coordinate of the destination -
destY - the y coordinate of the destination -
x - the x coordinate of the source -
y - the y coordinate of the source -
width - the width of the area -
height - the height of the area -
all - trueif children should be scrolled, and false otherwise
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Throws:
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setCaret
public 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.
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Parameters:
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caret - the new caret for the receiver, may be null
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Throws:
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IllegalArgumentException
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- ERROR_INVALID_ARGUMENT - if the caret has been disposed
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
setFont
public void setFont(
Font font)
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Description copied from class:
Control
- Sets the font that the receiver will use to paint textual information
to the font specified by the argument, or to the default font for that
kind of control if the argument is null.
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Overrides:
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setFont
in class
Control
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Parameters:
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font - the new font (or null)
setIME
public void setIME(
IME ime)
- Sets the receiver's IME.
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Parameters:
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ime - the new IME for the receiver, may be null
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Throws:
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IllegalArgumentException
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- ERROR_INVALID_ARGUMENT - if the IME has been disposed
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SWTException
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- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
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Since:
- 3.4
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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