GraphicAttribute.java

package and.awt.font;

import net.pbdavey.awt.Graphics2D;
import and.awt.Font;
import and.awt.Shape;
import and.awt.geom.AffineTransform;
import and.awt.geom.Rectangle2D;

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 <code>GraphicAttribute</code>.
	     * Subclasses use this to define the alignment of the graphic.
	     * @param alignment an int representing one of the
	     * <code>GraphicAttribute</code> 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 <code>GraphicAttribute</code>.  A
	     * graphic can be rendered above its ascent.
	     * @return the ascent of this <code>GraphicAttribute</code>.
	     * @see #getBounds()
	     */
	    public abstract float getAscent();


	    /**
	     * Returns the descent of this <code>GraphicAttribute</code>.  A
	     * graphic can be rendered below its descent.
	     * @return the descent of this <code>GraphicAttribute</code>.
	     * @see #getBounds()
	     */
	    public abstract float getDescent();

	    /**
	     * Returns the advance of this <code>GraphicAttribute</code>.  The
	     * <code>GraphicAttribute</code> 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 <code>GraphicAttribute</code>.
	     * @see #getBounds()
	     */
	    public abstract float getAdvance();

	    /**
	     * Returns a {@link Rectangle2D} that encloses all of the
	     * bits drawn by this <code>GraphicAttribute</code> 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 <code>Rectangle2D</code> that encloses all of the bits
	     * rendered by this <code>GraphicAttribute</code>.
	     */
	    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 <code>GraphicAttribute</code> 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 <code>getBounds</code>.
	     * 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 <code>GraphicAttribute</code>. This can be null.
	     * @return a <code>Shape</code> 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 <code>GraphicAttribute</code> 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 <code>GraphicAttribute</code>.
	     * Alignment can be to a particular baseline, or to the absolute top
	     * or bottom of a line.
	     * @return the alignment of this <code>GraphicAttribute</code>.
	     */
	    public final int getAlignment() {

	        return fAlignment;
	    }

	    /**
	     * Returns the justification information for this
	     * <code>GraphicAttribute</code>.  Subclasses
	     * can override this method to provide different justification
	     * information.
	     * @return a {@link GlyphJustificationInfo} object that contains the
	     * justification information for this <code>GraphicAttribute</code>.
	     */
	    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
	    }

}