Class Canvas
- java.lang.Object
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- org.eclipse.swt.widgets.Widget
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- org.eclipse.swt.widgets.Control
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- org.eclipse.swt.widgets.Scrollable
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- org.eclipse.swt.widgets.Composite
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- org.eclipse.swt.widgets.Canvas
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- All Implemented Interfaces:
Drawable
- Direct Known Subclasses:
AbstractHyperlink
,AnimatedProgress
,CLabel
,Decorations
,ExpandableComposite
,FormText
,GLCanvas
,StyledText
,TableCursor
,TreeCursor
public class Canvas extends Composite
Instances of this class provide a surface for drawing arbitrary graphics.- Styles:
- (none)
- 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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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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.Caret
getCaret()
Returns the caret.IME
getIME()
Returns the IME.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.void
setCaret(Caret caret)
Sets the receiver's caret.void
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
setIME(IME ime)
Sets the receiver's IME.-
Methods inherited from class org.eclipse.swt.widgets.Composite
changed, checkSubclass, drawBackground, getBackgroundMode, getChildren, getLayout, getLayoutDeferred, getTabList, isLayoutDeferred, layout, layout, layout, layout, layout, setBackgroundMode, setFocus, setLayout, setLayoutDeferred, setTabList, toString
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Methods inherited from class org.eclipse.swt.widgets.Scrollable
computeTrim, getClientArea, getHorizontalBar, getScrollbarsMode, getVerticalBar
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Methods inherited from class org.eclipse.swt.widgets.Control
addControlListener, addDragDetectListener, addFocusListener, addGestureListener, addHelpListener, addKeyListener, addMenuDetectListener, addMouseListener, addMouseMoveListener, addMouseTrackListener, addMouseWheelListener, addPaintListener, addTouchListener, addTraverseListener, computeSize, computeSize, dragDetect, dragDetect, forceFocus, getAccessible, getBackground, getBackgroundImage, getBorderWidth, getBounds, getCursor, getDragDetect, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getOrientation, getParent, getRegion, getShell, getSize, getTextDirection, getToolTipText, getTouchEnabled, getVisible, internal_dispose_GC, internal_new_GC, isEnabled, isFocusControl, isReparentable, isVisible, moveAbove, moveBelow, pack, pack, print, redraw, redraw, removeControlListener, removeDragDetectListener, removeFocusListener, removeGestureListener, removeHelpListener, removeKeyListener, removeMenuDetectListener, removeMouseListener, removeMouseMoveListener, removeMouseTrackListener, removeMouseWheelListener, removePaintListener, removeTouchListener, removeTraverseListener, requestLayout, setBackground, setBackgroundImage, setBounds, setBounds, setCapture, setCursor, setDragDetect, setEnabled, setForeground, setLayoutData, setLocation, setLocation, setMenu, setOrientation, setParent, setRedraw, setRegion, setSize, setSize, setTextDirection, setToolTipText, setTouchEnabled, setVisible, toControl, toControl, toDisplay, toDisplay, traverse, traverse, traverse, update
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Methods inherited from class org.eclipse.swt.widgets.Widget
addDisposeListener, addListener, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, isAutoDirection, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, reskin, setData, setData
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.eclipse.swt.graphics.Drawable
isAutoScalable
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Constructor Detail
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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 theint
"|" operator) two or more of thoseSWT
style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.- Parameters:
parent
- a composite control which will be the parent of the new instance (cannot be null)style
- the style of control to construct- Throws:
IllegalArgumentException
-- ERROR_NULL_ARGUMENT - if the parent is null
SWTException
-- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
- See Also:
SWT
,Widget.getStyle()
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Method Detail
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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:
gc
- the gc where the rectangle is to be filledx
- the x coordinate of the rectangle to be filledy
- the y coordinate of the rectangle to be filledwidth
- the width of the rectangle to be filledheight
- the height of the rectangle to be filled- Throws:
IllegalArgumentException
-- ERROR_NULL_ARGUMENT - if the gc is null
- ERROR_INVALID_ARGUMENT - if the gc has been disposed
SWTException
-- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
- Since:
- 3.2
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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.
- Returns:
- the caret for the receiver, may be null
- Throws:
SWTException
-- 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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getIME
public IME getIME()
Returns the IME.- Returns:
- the IME
- Throws:
SWTException
-- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
- Since:
- 3.4
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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, all outstanding paint events are flushed before the source area is copied to ensure that the contents of the canvas are drawn correctly.- Parameters:
destX
- the x coordinate of the destinationdestY
- the y coordinate of the destinationx
- the x coordinate of the sourcey
- the y coordinate of the sourcewidth
- the width of the areaheight
- the height of the areaall
-true
if children should be scrolled, andfalse
otherwise- Throws:
SWTException
-- 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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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.
- Parameters:
caret
- the new caret for the receiver, may be null- Throws:
IllegalArgumentException
-- ERROR_INVALID_ARGUMENT - if the caret has been disposed
SWTException
-- 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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setFont
public void setFont(Font font)
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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setIME
public void setIME(IME ime)
Sets the receiver's IME.- Parameters:
ime
- the new IME for the receiver, may be null- Throws:
IllegalArgumentException
-- ERROR_INVALID_ARGUMENT - if the IME has been disposed
SWTException
-- ERROR_WIDGET_DISPOSED - if the receiver has been disposed
- ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
- Since:
- 3.4
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