org.dvb.ui

Class DVBGraphics

java.lang.Object

java.awt.Graphics

org.dvb.ui.DVBGraphics

public abstract class DVBGraphics
extends Graphics

The DVBGraphics class is a adapter class to support alpha compositing in an MHP device. Most methods directly delegate to java.awt.Graphics other methods could delegate to the appropriate methods in java.awt.Graphics2D where available or could be implemented in native code. In implementations where the class java.awt.Graphics2D is visible to MHP applications, org.dvb.ui.DVBGraphics inherits from java.awt.Graphics2D. Otherwise, org.dvb.ui.DVBGraphics inherits from java.awt.Graphics. In MHP devices all Graphics Objects are DVBGraphics objects. Thus one can get a DVBGraphics by casting a given Graphics object. The normal compositing rule used is DVBAlphaComposite.SRC_OVER. Note that the default rule of SRC_OVER may not give the highest performance. Under many circumstances, applications will find that the SRC rule will give higher performance. The intersection between setDVBCompsite in this class and the setPaintMode and setXORMode methods inherited from java.awt.Graphics shall be as follows.

• Calling setPaintMode on an instance of this class shall be equivalent to calling setDVBComposite(DVBAlphaComposite.SrcOver).
• Calling setXORMode on an instance of this class shall be equivalent to calling setDVBComposite with a special and implementation dependent DVBAlphaComposite object which implements the semantics specified for this method in the parent class.
• Calling getDVBComposite when setXORMode is the last DVBComposite set shall return this implementation dependent object. Conformant MHP applications shall not do anything with or to this object including calling any methods on it.
• The present document does not tighten, refine or detail the definition of the setXORMode beyond what is specified for the parent class.

Note: Implementations of XOR mode may change colours with alpha to without and vice versa (reversibly).

Since:

MHP1.0

See Also:

Graphics

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DVBGraphics() Constructs a new DVBGraphics object.

Method Summary

Methods

Modifier and Type	Method and Description
abstract int[]	getAvailableCompositeRules() Returns all available Porter-Duff Rules for this specific Graphics context.
DVBColor	getBestColorMatch(Color c) Returns the best match for the specified Color as a DVBColor, in a device-dependent manner, as constrained by the MHP graphics reference model.
abstract Color	getColor() Gets this graphics context's current color.
abstract DVBAlphaComposite	getDVBComposite() Returns the current DVBAlphaComposite in the DVBGraphics context.
int	getType() Returns the Sample Model (DVBBufferedImage.TYPE_BASE, DVBBufferedImage.TYPE_ADVANCED) which is used in the on/off screen buffer this graphics object draws into.
abstract void	setColor(Color c) Sets this graphics context's current color to the specified color.
abstract void	setDVBComposite(DVBAlphaComposite comp) Sets the DVBAlphaComposite for the DVBGraphics context.
String	toString() Returns a String object representing this DVBGraphics object's value.

Methods inherited from class java.awt.Graphics

clearRect, clipRect, copyArea, create, create, dispose, draw3DRect, drawArc, drawBytes, drawChars, drawImage, drawImage, drawImage, drawImage, drawImage, drawImage, drawLine, drawOval, drawPolygon, drawPolygon, drawPolyline, drawRect, drawRoundRect, drawString, drawString, fill3DRect, fillArc, fillOval, fillPolygon, fillPolygon, fillRect, fillRoundRect, finalize, getClip, getClipBounds, getClipBounds, getFont, getFontMetrics, getFontMetrics, hitClip, setClip, setClip, setFont, setPaintMode, setXORMode, translate

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DVBGraphics

protected DVBGraphics()

Constructs a new DVBGraphics object. This constructor is the default constructor for a graphics context.

Since DVBGraphics is an abstract class, applications cannot call this constructor directly. DVBGraphics contexts are obtained from other DVBGraphics contexts or are created by casting java.awt.Graphics to DVBGraphics.

Since:

MHP 1.0

See Also:

Graphics.create(), Component.getGraphics()

Method Detail

getAvailableCompositeRules

public abstract int[] getAvailableCompositeRules()

Returns all available Porter-Duff Rules for this specific Graphics context. E.g. a devices could support the SRC_OVER rule when using a destination which does not have Alpha or where the alpha is null, while this rule is not available when drawing on a graphic context where the destination has alpha. Which rules are supported for the different graphics objects is defined in the Minimum Platform Capabilities of the MHP spec.

Returns:

all available Porter-Duff Rules for this specific Graphics context.

Since:

MHP 1.0

getBestColorMatch

public DVBColor getBestColorMatch(Color c)

Returns the best match for the specified Color as a DVBColor, in a device-dependent manner, as constrained by the MHP graphics reference model.

Parameters:

c - the specified Color.

Returns:

the best DVBColor match for the specified Color.

Since:

MHP 1.0

getColor

public abstract Color getColor()

Gets this graphics context's current color. This will return a DVBColor cast to java.awt.Color.

Specified by:

getColor in class Graphics

Returns:

this graphics context's current color.

Since:

MHP 1.0

See Also:

DVBColor, Color, setColor(java.awt.Color)

getDVBComposite

public abstract DVBAlphaComposite getDVBComposite()

Returns the current DVBAlphaComposite in the DVBGraphics context. This method could delegate to a java.awt.Graphics2D object where available

Returns:

the current DVBGraphics DVBAlphaComposite, which defines a compositing style.

Since:

MHP 1.0

See Also:

setDVBComposite(org.dvb.ui.DVBAlphaComposite)

getType

public int getType()

Returns the Sample Model (DVBBufferedImage.TYPE_BASE, DVBBufferedImage.TYPE_ADVANCED) which is used in the on/off screen buffer this graphics object draws into.

Returns:

the type of the Sample Model

Since:

MHP 1.0

See Also:

DVBBufferedImage

setColor

public abstract void setColor(Color c)

Sets this graphics context's current color to the specified color. All subsequent graphics operations using this graphics context use this specified color. Note that color c can be a DVBColor

Specified by:

setColor in class Graphics

Parameters:

c - the new rendering color.

Since:

MHP 1.0

See Also:

Color, DVBColor, getColor()

setDVBComposite

public abstract void setDVBComposite(DVBAlphaComposite comp)
                              throws UnsupportedDrawingOperationException

Sets the DVBAlphaComposite for the DVBGraphics context. The DVBAlphaComposite is used in all drawing methods such as drawImage, drawString, draw, and fill. It specifies how new pixels are to be combined with the existing pixels on the graphics device during the rendering process.

This method could delegate to a Graphics2D object or to an native implementation

Parameters:

comp - the DVBAlphaComposite object to be used for rendering

Throws:

UnsupportedDrawingOperationException - when the requested Porter-Duff rule is not supported by this graphics context

Since:

MHP 1.0

See Also:

Graphics.setXORMode(java.awt.Color), Graphics.setPaintMode(), DVBAlphaComposite

toString

public String toString()

Returns a String object representing this DVBGraphics object's value.

Overrides:

toString in class Graphics

Returns:

a string representation of this graphics context.

Since:

MHP 1.0