src/java.desktop/share/classes/java/awt/font/GlyphVector.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/*
 * @author Charlton Innovations, Inc.
 */

package java.awt.font;

import java.awt.Graphics2D;
import java.awt.Font;
import java.awt.Polygon;        // remind - need a floating point version
import java.awt.Rectangle;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.AffineTransform;
import java.awt.Shape;
import java.awt.font.GlyphMetrics;
import java.awt.font.GlyphJustificationInfo;

/**
 * A {@code GlyphVector} object is a collection of glyphs
 * containing geometric information for the placement of each glyph
 * in a transformed coordinate space which corresponds to the
 * device on which the {@code GlyphVector} is ultimately
 * displayed.
 * <p>
 * The {@code GlyphVector} does not attempt any interpretation of
 * the sequence of glyphs it contains.  Relationships between adjacent
 * glyphs in sequence are solely used to determine the placement of
 * the glyphs in the visual coordinate space.
 * <p>
 * Instances of {@code GlyphVector} are created by a {@link Font}.
 * <p>
 * In a text processing application that can cache intermediate
 * representations of text, creation and subsequent caching of a
 * {@code GlyphVector} for use during rendering is the fastest
 * method to present the visual representation of characters to a user.
 * <p>
 * A {@code GlyphVector} is associated with exactly one
 * {@code Font}, and can provide data useful only in relation to
 * this {@code Font}.  In addition, metrics obtained from a
 * {@code GlyphVector} are not generally geometrically scalable
 * since the pixelization and spacing are dependent on grid-fitting
 * algorithms within a {@code Font}.  To facilitate accurate
 * measurement of a {@code GlyphVector} and its component
 * glyphs, you must specify a scaling transform, anti-alias mode, and
 * fractional metrics mode when creating the {@code GlyphVector}.
 * These characteristics can be derived from the destination device.
 * <p>
 * For each glyph in the {@code GlyphVector}, you can obtain:
 * <ul>
 * <li>the position of the glyph
 * <li>the transform associated with the glyph
 * <li>the metrics of the glyph in the context of the
 *   {@code GlyphVector}.  The metrics of the glyph may be
 *   different under different transforms, application specified
 *   rendering hints, and the specific instance of the glyph within
 *   the {@code GlyphVector}.
 * </ul>
 * <p>
 * Altering the data used to create the {@code GlyphVector} does not
 * alter the state of the {@code GlyphVector}.
 * <p>
 * Methods are provided to adjust the positions of the glyphs
 * within the {@code GlyphVector}.  These methods are most
 * appropriate for applications that are performing justification
 * operations for the presentation of the glyphs.
 * <p>
 * Methods are provided to transform individual glyphs within the
 * {@code GlyphVector}.  These methods are primarily useful for
 * special effects.
 * <p>
 * Methods are provided to return both the visual, logical, and pixel bounds
 * of the entire {@code GlyphVector} or of individual glyphs within
 * the {@code GlyphVector}.
 * <p>
 * Methods are provided to return a {@link Shape} for the
 * {@code GlyphVector}, and for individual glyphs within the
 * {@code GlyphVector}.
 * @see Font
 * @see GlyphMetrics
 * @see TextLayout
 * @author Charlton Innovations, Inc.
 */

public abstract class GlyphVector implements Cloneable {

    /**
     * Constructor for subclasses to call.
     */
    protected GlyphVector() {}

    //
    // methods associated with creation-time state
    //

    /**
     * Returns the {@code Font} associated with this
     * {@code GlyphVector}.
     * @return {@code Font} used to create this
     * {@code GlyphVector}.
     * @see Font
     */
    public abstract Font getFont();

    /**
     * Returns the {@link FontRenderContext} associated with this
     * {@code GlyphVector}.
     * @return {@code FontRenderContext} used to create this
     * {@code GlyphVector}.
     * @see FontRenderContext
     * @see Font
     */
    public abstract FontRenderContext getFontRenderContext();

    //
    // methods associated with the GlyphVector as a whole
    //

    /**
     * Assigns default positions to each glyph in this
     * {@code GlyphVector}. This can destroy information
     * generated during initial layout of this {@code GlyphVector}.
     */
    public abstract void performDefaultLayout();

    /**
     * Returns the number of glyphs in this {@code GlyphVector}.
     * @return number of glyphs in this {@code GlyphVector}.
     */
    public abstract int getNumGlyphs();

    /**
     * Returns the glyphcode of the specified glyph.
     * This return value is meaningless to anything other
     * than the {@code Font} object that created this
     * {@code GlyphVector}.
     * @param glyphIndex the index into this {@code GlyphVector}
     * that corresponds to the glyph from which to retrieve the
     * glyphcode.
     * @return the glyphcode of the glyph at the specified
     * {@code glyphIndex}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     * is less than 0 or greater than or equal to the
     * number of glyphs in this {@code GlyphVector}
     */
    public abstract int getGlyphCode(int glyphIndex);

    /**
     * Returns an array of glyphcodes for the specified glyphs.
     * The contents of this return value are meaningless to anything other
     * than the {@code Font} used to create this
     * {@code GlyphVector}.  This method is used
     * for convenience and performance when processing glyphcodes.
     * If no array is passed in, a new array is created.
     * @param beginGlyphIndex the index into this
     *   {@code GlyphVector} at which to start retrieving glyphcodes
     * @param numEntries the number of glyphcodes to retrieve
     * @param codeReturn the array that receives the glyphcodes and is
     *   then returned
     * @return an array of glyphcodes for the specified glyphs.
     * @throws IllegalArgumentException if {@code numEntries} is
     *   less than 0
     * @throws IndexOutOfBoundsException if {@code beginGlyphIndex}
     *   is less than 0
     * @throws IndexOutOfBoundsException if the sum of
     *   {@code beginGlyphIndex} and {@code numEntries} is
     *   greater than the number of glyphs in this
     *   {@code GlyphVector}
     */
    public abstract int[] getGlyphCodes(int beginGlyphIndex, int numEntries,
                                        int[] codeReturn);

    /**
     * Returns the character index of the specified glyph.
     * The character index is the index of the first logical
     * character represented by the glyph.  The default
     * implementation assumes a one-to-one, left-to-right mapping
     * of glyphs to characters.
     * @param glyphIndex the index of the glyph
     * @return the index of the first character represented by the glyph
     * @since 1.4
     */
    public int getGlyphCharIndex(int glyphIndex) {
        return glyphIndex;
    }

    /**
     * Returns the character indices of the specified glyphs.
     * The character index is the index of the first logical
     * character represented by the glyph.  Indices are returned
     * in glyph order.  The default implementation invokes
     * getGlyphCharIndex for each glyph, and subclassers will probably
     * want to override this implementation for performance reasons.
     * Use this method for convenience and performance
     * in processing of glyphcodes. If no array is passed in,
     * a new array is created.
     * @param beginGlyphIndex the index of the first glyph
     * @param numEntries the number of glyph indices
     * @param codeReturn the array into which to return the character indices
     * @return an array of character indices, one per glyph.
     * @since 1.4
     */
    public int[] getGlyphCharIndices(int beginGlyphIndex, int numEntries,
                                     int[] codeReturn) {
        if (codeReturn == null) {
            codeReturn = new int[numEntries];
        }
        for (int i = 0, j = beginGlyphIndex; i < numEntries; ++i, ++j) {
            codeReturn[i] = getGlyphCharIndex(j);
        }
        return codeReturn;
     }

    /**
     * Returns the logical bounds of this {@code GlyphVector}.
     * This method is used when positioning this {@code GlyphVector}
     * in relation to visually adjacent {@code GlyphVector} objects.
     * @return a {@link Rectangle2D} that is the logical bounds of this
     * {@code GlyphVector}.
     */
    public abstract Rectangle2D getLogicalBounds();

    /**
     * Returns the visual bounds of this {@code GlyphVector}
     * The visual bounds is the bounding box of the outline of this
     * {@code GlyphVector}.  Because of rasterization and
     * alignment of pixels, it is possible that this box does not
     * enclose all pixels affected by rendering this {@code GlyphVector}.
     * @return a {@code Rectangle2D} that is the bounding box
     * of this {@code GlyphVector}.
     */
    public abstract Rectangle2D getVisualBounds();

    /**
     * Returns the pixel bounds of this {@code GlyphVector} when
     * rendered in a graphics with the given
     * {@code FontRenderContext} at the given location.  The
     * renderFRC need not be the same as the
     * {@code FontRenderContext} of this
     * {@code GlyphVector}, and can be null.  If it is null, the
     * {@code FontRenderContext} of this {@code GlyphVector}
     * is used.  The default implementation returns the visual bounds,
     * offset to x, y and rounded out to the next integer value (i.e. returns an
     * integer rectangle which encloses the visual bounds) and
     * ignores the FRC.  Subclassers should override this method.
     * @param renderFRC the {@code FontRenderContext} of the {@code Graphics}.
     * @param x the x-coordinate at which to render this {@code GlyphVector}.
     * @param y the y-coordinate at which to render this {@code GlyphVector}.
     * @return a {@code Rectangle} bounding the pixels that would be affected.
     * @since 1.4
     */
    public Rectangle getPixelBounds(FontRenderContext renderFRC, float x, float y) {
                Rectangle2D rect = getVisualBounds();
                int l = (int)Math.floor(rect.getX() + x);
                int t = (int)Math.floor(rect.getY() + y);
                int r = (int)Math.ceil(rect.getMaxX() + x);
                int b = (int)Math.ceil(rect.getMaxY() + y);
                return new Rectangle(l, t, r - l, b - t);
        }


    /**
     * Returns a {@code Shape} whose interior corresponds to the
     * visual representation of this {@code GlyphVector}.
     * @return a {@code Shape} that is the outline of this
     * {@code GlyphVector}.
     */
    public abstract Shape getOutline();

    /**
     * Returns a {@code Shape} whose interior corresponds to the
     * visual representation of this {@code GlyphVector} when
     * rendered at x,&nbsp;y.
     * @param x the X coordinate of this {@code GlyphVector}.
     * @param y the Y coordinate of this {@code GlyphVector}.
     * @return a {@code Shape} that is the outline of this
     *   {@code GlyphVector} when rendered at the specified
     *   coordinates.
     */
    public abstract Shape getOutline(float x, float y);

    /**
     * Returns a {@code Shape} whose interior corresponds to the
     * visual representation of the specified glyph
     * within this {@code GlyphVector}.
     * The outline returned by this method is positioned around the
     * origin of each individual glyph.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @return a {@code Shape} that is the outline of the glyph
     *   at the specified {@code glyphIndex} of this
     *   {@code GlyphVector}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     */
    public abstract Shape getGlyphOutline(int glyphIndex);

    /**
     * Returns a {@code Shape} whose interior corresponds to the
     * visual representation of the specified glyph
     * within this {@code GlyphVector}, offset to x,&nbsp;y.
     * The outline returned by this method is positioned around the
     * origin of each individual glyph.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @param x the X coordinate of the location of this {@code GlyphVector}
     * @param y the Y coordinate of the location of this {@code GlyphVector}
     * @return a {@code Shape} that is the outline of the glyph
     *   at the specified {@code glyphIndex} of this
     *   {@code GlyphVector} when rendered at the specified
     *   coordinates.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     * @since 1.4
     */
    public Shape getGlyphOutline(int glyphIndex, float x, float y) {
        Shape s = getGlyphOutline(glyphIndex);
        AffineTransform at = AffineTransform.getTranslateInstance(x,y);
        return at.createTransformedShape(s);
        }

    /**
     * Returns the position of the specified glyph relative to the
     * origin of this {@code GlyphVector}.
     * If {@code glyphIndex} equals the number of glyphs in
     * this {@code GlyphVector}, this method returns the position after
     * the last glyph. This position is used to define the advance of
     * the entire {@code GlyphVector}.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @return a {@link Point2D} object that is the position of the glyph
     *   at the specified {@code glyphIndex}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than the number of glyphs
     *   in this {@code GlyphVector}
     * @see #setGlyphPosition
     */
    public abstract Point2D getGlyphPosition(int glyphIndex);

    /**
     * Sets the position of the specified glyph within this
     * {@code GlyphVector}.
     * If {@code glyphIndex} equals the number of glyphs in
     * this {@code GlyphVector}, this method sets the position after
     * the last glyph. This position is used to define the advance of
     * the entire {@code GlyphVector}.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @param newPos the {@code Point2D} at which to position the
     *   glyph at the specified {@code glyphIndex}
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than the number of glyphs
     *   in this {@code GlyphVector}
     * @see #getGlyphPosition
     */
    public abstract void setGlyphPosition(int glyphIndex, Point2D newPos);

    /**
     * Returns the transform of the specified glyph within this
     * {@code GlyphVector}.  The transform is relative to the
     * glyph position.  If no special transform has been applied,
     * {@code null} can be returned.  A null return indicates
     * an identity transform.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @return an {@link AffineTransform} that is the transform of
     *   the glyph at the specified {@code glyphIndex}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     * @see #setGlyphTransform
     */
    public abstract AffineTransform getGlyphTransform(int glyphIndex);

    /**
     * Sets the transform of the specified glyph within this
     * {@code GlyphVector}.  The transform is relative to the glyph
     * position.  A {@code null} argument for {@code newTX}
     * indicates that no special transform is applied for the specified
     * glyph.
     * This method can be used to rotate, mirror, translate and scale the
     * glyph.  Adding a transform can result in significant performance changes.
     * @param glyphIndex the index into this {@code GlyphVector}
     * @param newTX the new transform of the glyph at {@code glyphIndex}
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     * @see #getGlyphTransform
     */
    public abstract void setGlyphTransform(int glyphIndex, AffineTransform newTX);

    /**
     * Returns flags describing the global state of the GlyphVector.
     * Flags not described below are reserved.  The default
     * implementation returns 0 (meaning false) for the position adjustments,
     * transforms, rtl, and complex flags.
     * Subclassers should override this method, and make sure
     * it correctly describes the GlyphVector and corresponds
     * to the results of related calls.
     * @return an int containing the flags describing the state
     * @see #FLAG_HAS_POSITION_ADJUSTMENTS
     * @see #FLAG_HAS_TRANSFORMS
     * @see #FLAG_RUN_RTL
     * @see #FLAG_COMPLEX_GLYPHS
     * @see #FLAG_MASK
     * @since 1.4
     */
    public int getLayoutFlags() {
                return 0;
        }

    /**
     * A flag used with getLayoutFlags that indicates that this {@code GlyphVector} has
     * per-glyph transforms.
     * @since 1.4
     */
    public static final int FLAG_HAS_TRANSFORMS = 1;

    /**
     * A flag used with getLayoutFlags that indicates that this {@code GlyphVector} has
     * position adjustments.  When this is true, the glyph positions don't match the
     * accumulated default advances of the glyphs (for example, if kerning has been done).
     * @since 1.4
     */
    public static final int FLAG_HAS_POSITION_ADJUSTMENTS = 2;

    /**
     * A flag used with getLayoutFlags that indicates that this {@code GlyphVector} has
     * a right-to-left run direction.  This refers to the glyph-to-char mapping and does
     * not imply that the visual locations of the glyphs are necessarily in this order,
     * although generally they will be.
     * @since 1.4
     */
    public static final int FLAG_RUN_RTL = 4;

    /**
     * A flag used with getLayoutFlags that indicates that this {@code GlyphVector} has
     * a complex glyph-to-char mapping (one that does not map glyphs to chars one-to-one in
     * strictly ascending or descending order matching the run direction).
     * @since 1.4
     */
    public static final int FLAG_COMPLEX_GLYPHS = 8;

    /**
     * A mask for supported flags from getLayoutFlags.  Only bits covered by the mask
     * should be tested.
     * @since 1.4
     */
    public static final int FLAG_MASK =
        FLAG_HAS_TRANSFORMS |
        FLAG_HAS_POSITION_ADJUSTMENTS |
        FLAG_RUN_RTL |
        FLAG_COMPLEX_GLYPHS;

    /**
     * Returns an array of glyph positions for the specified glyphs.
     * This method is used for convenience and performance when
     * processing glyph positions.
     * If no array is passed in, a new array is created.
     * Even numbered array entries beginning with position zero are the X
     * coordinates of the glyph numbered {@code beginGlyphIndex + position/2}.
     * Odd numbered array entries beginning with position one are the Y
     * coordinates of the glyph numbered {@code beginGlyphIndex + (position-1)/2}.
     * If {@code beginGlyphIndex} equals the number of glyphs in
     * this {@code GlyphVector}, this method gets the position after
     * the last glyph and this position is used to define the advance of
     * the entire {@code GlyphVector}.
     * @param beginGlyphIndex the index at which to begin retrieving
     *   glyph positions
     * @param numEntries the number of glyphs to retrieve
     * @param positionReturn the array that receives the glyph positions
     *   and is then returned.
     * @return an array of glyph positions specified by
     *  {@code beginGlyphIndex} and {@code numEntries}.
     * @throws IllegalArgumentException if {@code numEntries} is
     *   less than 0
     * @throws IndexOutOfBoundsException if {@code beginGlyphIndex}
     *   is less than 0
     * @throws IndexOutOfBoundsException if the sum of
     *   {@code beginGlyphIndex} and {@code numEntries}
     *   is greater than the number of glyphs in this
     *   {@code GlyphVector} plus one
     */
    public abstract float[] getGlyphPositions(int beginGlyphIndex, int numEntries,
                                              float[] positionReturn);

    /**
     * Returns the logical bounds of the specified glyph within this
     * {@code GlyphVector}.
     * These logical bounds have a total of four edges, with two edges
     * parallel to the baseline under the glyph's transform and the other two
     * edges are shared with adjacent glyphs if they are present.  This
     * method is useful for hit-testing of the specified glyph,
     * positioning of a caret at the leading or trailing edge of a glyph,
     * and for drawing a highlight region around the specified glyph.
     * @param glyphIndex the index into this {@code GlyphVector}
     *   that corresponds to the glyph from which to retrieve its logical
     *   bounds
     * @return  a {@code Shape} that is the logical bounds of the
     *   glyph at the specified {@code glyphIndex}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     * @see #getGlyphVisualBounds
     */
    public abstract Shape getGlyphLogicalBounds(int glyphIndex);

    /**
     * Returns the visual bounds of the specified glyph within the
     * {@code GlyphVector}.
     * The bounds returned by this method is positioned around the
     * origin of each individual glyph.
     * @param glyphIndex the index into this {@code GlyphVector}
     *   that corresponds to the glyph from which to retrieve its visual
     *   bounds
     * @return a {@code Shape} that is the visual bounds of the
     *   glyph at the specified {@code glyphIndex}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     * @see #getGlyphLogicalBounds
     */
    public abstract Shape getGlyphVisualBounds(int glyphIndex);

    /**
     * Returns the pixel bounds of the glyph at index when this
     * {@code GlyphVector} is rendered in a {@code Graphics} with the
     * given {@code FontRenderContext} at the given location. The
     * renderFRC need not be the same as the
     * {@code FontRenderContext} of this
     * {@code GlyphVector}, and can be null.  If it is null, the
     * {@code FontRenderContext} of this {@code GlyphVector}
     * is used.  The default implementation returns the visual bounds of the glyph,
     * offset to x, y and rounded out to the next integer value, and
     * ignores the FRC.  Subclassers should override this method.
     * @param index the index of the glyph.
     * @param renderFRC the {@code FontRenderContext} of the {@code Graphics}.
     * @param x the X position at which to render this {@code GlyphVector}.
     * @param y the Y position at which to render this {@code GlyphVector}.
     * @return a {@code Rectangle} bounding the pixels that would be affected.
     * @since 1.4
     */
    public Rectangle getGlyphPixelBounds(int index, FontRenderContext renderFRC, float x, float y) {
                Rectangle2D rect = getGlyphVisualBounds(index).getBounds2D();
                int l = (int)Math.floor(rect.getX() + x);
                int t = (int)Math.floor(rect.getY() + y);
                int r = (int)Math.ceil(rect.getMaxX() + x);
                int b = (int)Math.ceil(rect.getMaxY() + y);
                return new Rectangle(l, t, r - l, b - t);
        }

    /**
     * Returns the metrics of the glyph at the specified index into
     * this {@code GlyphVector}.
     * @param glyphIndex the index into this {@code GlyphVector}
     *   that corresponds to the glyph from which to retrieve its metrics
     * @return a {@link GlyphMetrics} object that represents the
     *   metrics of the glyph at the specified {@code glyphIndex}
     *   into this {@code GlyphVector}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     */
    public abstract GlyphMetrics getGlyphMetrics(int glyphIndex);

    /**
     * Returns the justification information for the glyph at
     * the specified index into this {@code GlyphVector}.
     * @param glyphIndex the index into this {@code GlyphVector}
     *   that corresponds to the glyph from which to retrieve its
     *   justification properties
     * @return a {@link GlyphJustificationInfo} object that
     *   represents the justification properties of the glyph at the
     *   specified {@code glyphIndex} into this
     *   {@code GlyphVector}.
     * @throws IndexOutOfBoundsException if {@code glyphIndex}
     *   is less than 0 or greater than or equal to the number
     *   of glyphs in this {@code GlyphVector}
     */
    public abstract GlyphJustificationInfo getGlyphJustificationInfo(int glyphIndex);

    //
    // general utility methods
    //

    /**
     * Tests if the specified {@code GlyphVector} exactly
     * equals this {@code GlyphVector}.
     * @param set the specified {@code GlyphVector} to test
     * @return {@code true} if the specified
     *   {@code GlyphVector} equals this {@code GlyphVector};
     *   {@code false} otherwise.
     */
    public abstract boolean equals(GlyphVector set);
}