Class GC

protected GC(Drawable target)

Protected constructor, because GC.create(target) should be used instead.

public void clearArea(int x,
                      int y,
                      int w,
                      int h,
                      boolean exposures)

Clear area using the background pixel or pixmap of the drawable. Note that this operation does not adhere to the current clip.

public Object clone()

Try to get a suitable GC from the drawable's cache. If there isn't one, create one.

Overrides:

clone in interface Object

public void copyArea(Drawable source,
                     int srcX,
                     int srcY,
                     int destX,
                     int destY,
                     int width,
                     int height)

public GC create()

public static GC create(Drawable target)

Create a GC, or if one is already cached for target, return that.

Parameters:

target - The Drawable for which a GC is needed

Returns:

The new or retrieved GC

public void dispose()

Save this GC in the drawable's cache. The "real" dispose (disposeImpl) is called when the drawable is finialized, to free X server resources.

public void disposeImpl()

public void drawArc(int x,
                    int y,
                    int w,
                    int h,
                    int startAngle,
                    int arcAngle)

public void drawLine(int x1,
                     int y1,
                     int x2,
                     int y2)

public void drawPoint(int x,
                      int y)

Draw a point using the current foreground color

Parameters:

x - The x coordinate at which to draw

public void drawRectangle(int x,
                          int y,
                          int w,
                          int h)

public void drawString(String text,
                       int x,
                       int y)

public void fillArc(int x,
                    int y,
                    int w,
                    int h,
                    int startAngle,
                    int arcAngle)

public void fillPolygon(int[] xPoints,
                        int[] yPoints,
                        int nPoints,
                        int translateX,
                        int translateY)

public void fillRectangle(int x,
                          int y,
                          int w,
                          int h)

public void finalize()

Called on an object by the Virtual Machine at most once, at some point after the Object is determined unreachable but before it is destroyed. You would think that this means it eventually is called on every Object, but this is not necessarily the case. If execution terminates abnormally, garbage collection does not always happen. Thus you cannot rely on this method to always work. For finer control over garbage collection, use references from the java.lang.ref package.

Virtual Machines are free to not call this method if they can determine that it does nothing important; for example, if your class extends Object and overrides finalize to do simply super.finalize().

finalize() will be called by a Thread that has no locks on any Objects, and may be called concurrently. There are no guarantees on the order in which multiple objects are finalized. This means that finalize() is usually unsuited for performing actions that must be thread-safe, and that your implementation must be use defensive programming if it is to always work.

If an Exception is thrown from finalize() during garbage collection, it will be patently ignored and the Object will still be destroyed.

It is allowed, although not typical, for user code to call finalize() directly. User invocation does not affect whether automatic invocation will occur. It is also permitted, although not recommended, for a finalize() method to "revive" an object by making it reachable from normal code again.

Unlike constructors, finalize() does not get called for an object's superclass unless the implementation specifically calls super.finalize().

The default implementation does nothing.

Overrides:

finalize in interface Object

See Also:

System.gc(), System.runFinalizersOnExit(boolean), java.lang.ref

public Drawable getDrawable()

public void putImage(XImage image,
                     int srcX,
                     int srcY,
                     int destX,
                     int destY,
                     int width,
                     int height)

public void setClipRectangles(Rectangle[] rectangles)

Set the clip region for the graphics operations performed by the GC. This is one of the few costly operations of this class. It is suggested that the clip is only set or changed if really necessary. Higher level APIs can make such optimizations transparent.

Parameters:

rectangles - the union of these rectangles describe the clip region.

public void setFont(Font font)

public void setForeground(long pixel)