* The GraphicAttribute class represents a graphic embedded
* in text. Clients subclass this class to implement their own char
* replacement graphics. Clients wishing to embed shapes and images in
* text need not subclass this class. Instead, clients can use the
* {@link ShapeGraphicAttribute} and {@link ImageGraphicAttribute}
* classes.
*
* Subclasses must ensure that their objects are immutable once they
* are constructed. Mutating a GraphicAttribute that
* is used in a {@link TextLayout} results in undefined behavior from the
* TextLayout.
*/
public abstract class GraphicAttribute {
private int fAlignment;
/**
* Aligns top of graphic to top of line.
*/
public static final int TOP_ALIGNMENT = -1;
/**
* Aligns bottom of graphic to bottom of line.
*/
public static final int BOTTOM_ALIGNMENT = -2;
/**
* Aligns origin of graphic to roman baseline of line.
*/
public static final int ROMAN_BASELINE = Font.ROMAN_BASELINE;
/**
* Aligns origin of graphic to center baseline of line.
*/
public static final int CENTER_BASELINE = Font.CENTER_BASELINE;
/**
* Aligns origin of graphic to hanging baseline of line.
*/
public static final int HANGING_BASELINE = Font.HANGING_BASELINE;
/**
* Constructs a GraphicAttribute.
* Subclasses use this to define the alignment of the graphic.
* @param alignment an int representing one of the
* GraphicAttribute alignment fields
* @throws IllegalArgumentException if alignment is not one of the
* five defined values.
*/
protected GraphicAttribute(int alignment) {
if (alignment < BOTTOM_ALIGNMENT || alignment > HANGING_BASELINE) {
throw new IllegalArgumentException("bad alignment");
}
fAlignment = alignment;
}
/**
* Returns the ascent of this GraphicAttribute. A
* graphic can be rendered above its ascent.
* @return the ascent of this GraphicAttribute.
* @see #getBounds()
*/
public abstract float getAscent();
/**
* Returns the descent of this GraphicAttribute. A
* graphic can be rendered below its descent.
* @return the descent of this GraphicAttribute.
* @see #getBounds()
*/
public abstract float getDescent();
/**
* Returns the advance of this GraphicAttribute. The
* GraphicAttribute object's advance is the distance
* from the point at which the graphic is rendered and the point where
* the next character or graphic is rendered. A graphic can be
* rendered beyond its advance
* @return the advance of this GraphicAttribute.
* @see #getBounds()
*/
public abstract float getAdvance();
/**
* Returns a {@link Rectangle2D} that encloses all of the
* bits drawn by this GraphicAttribute relative to the
* rendering position.
* A graphic may be rendered beyond its origin, ascent, descent,
* or advance; but if it is, this method's implementation must
* indicate where the graphic is rendered.
* Default bounds is the rectangle (0, -ascent, advance, ascent+descent).
* @return a Rectangle2D that encloses all of the bits
* rendered by this GraphicAttribute.
*/
public Rectangle2D getBounds() {
float ascent = getAscent();
return new Rectangle2D.Float(0, -ascent,
getAdvance(), ascent+getDescent());
}
/**
* Return a {@link java.awt.Shape} that represents the region that
* this GraphicAttribute renders. This is used when a
* {@link TextLayout} is requested to return the outline of the text.
* The (untransformed) shape must not extend outside the rectangular
* bounds returned by getBounds.
* The default implementation returns the rectangle returned by
* {@link #getBounds}, transformed by the provided {@link AffineTransform}
* if present.
* @param tx an optional {@link AffineTransform} to apply to the
* outline of this GraphicAttribute. This can be null.
* @return a Shape representing this graphic attribute,
* suitable for stroking or filling.
* @since 1.6
*/
public Shape getOutline(AffineTransform tx) {
Shape b = getBounds();
if (tx != null) {
b = tx.createTransformedShape(b);
}
return b;
}
/**
* Renders this GraphicAttribute at the specified
* location.
* @param graphics the {@link Graphics2D} into which to render the
* graphic
* @param x the user-space X coordinate where the graphic is rendered
* @param y the user-space Y coordinate where the graphic is rendered
*/
public abstract void draw(Graphics2D graphics, float x, float y);
/**
* Returns the alignment of this GraphicAttribute.
* Alignment can be to a particular baseline, or to the absolute top
* or bottom of a line.
* @return the alignment of this GraphicAttribute.
*/
public final int getAlignment() {
return fAlignment;
}
/**
* Returns the justification information for this
* GraphicAttribute. Subclasses
* can override this method to provide different justification
* information.
* @return a {@link GlyphJustificationInfo} object that contains the
* justification information for this GraphicAttribute.
*/
public GlyphJustificationInfo getJustificationInfo() {
// should we cache this?
float advance = getAdvance();
return new GlyphJustificationInfo(
advance, // weight
false, // growAbsorb
2, // growPriority
advance/3, // growLeftLimit
advance/3, // growRightLimit
false, // shrinkAbsorb
1, // shrinkPriority
0, // shrinkLeftLimit
0); // shrinkRightLimit
}
}