/*
* @(#)GlyphMetrics.java 1.40 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
/*
* (C) Copyright Taligent, Inc. 1996 - 1997, All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998, All Rights Reserved
*
* The original version of this source code and documentation is
* copyrighted and owned by Taligent, Inc., a wholly-owned subsidiary
* of IBM. These materials are provided under terms of a License
* Agreement between Taligent and Sun. This technology is protected
* by multiple US and International patents.
*
* This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*
*/
package java.awt.font;
import java.awt.geom.Rectangle2D;
/**
* The <code>GlyphMetrics</code> class represents infomation for a
* single glyph. A glyph is the visual representation of one or more
* characters. Many different glyphs can be used to represent a single
* character or combination of characters. <code>GlyphMetrics</code>
* instances are produced by {@link java.awt.Font Font} and are applicable
* to a specific glyph in a particular <code>Font</code>.
* <p>
* Glyphs are either STANDARD, LIGATURE, COMBINING, or COMPONENT.
* <ul>
* <li>STANDARD glyphs are commonly used to represent single characters.
* <li>LIGATURE glyphs are used to represent sequences of characters.
* <li>COMPONENT glyphs in a {@link GlyphVector} do not correspond to a
* particular character in a text model. Instead, COMPONENT glyphs are
* added for typographical reasons, such as Arabic justification.
* <li>COMBINING glyphs embellish STANDARD or LIGATURE glyphs, such
* as accent marks. Carets do not appear before COMBINING glyphs.
* </ul>
* <p>
* Other metrics available through <code>GlyphMetrics</code> are the
* components of the advance, the visual bounds, and the left and right
* side bearings.
* <p>
* Glyphs for a rotated font, or obtained from a <code>GlyphVector</code>
* which has applied a rotation to the glyph, can have advances that
* contain both X and Y components. Usually the advance only has one
* component.
* <p>
* The advance of a glyph is the distance from the glyph's origin to the
* origin of the next glyph along the baseline, which is either vertical
* or horizontal. Note that, in a <code>GlyphVector</code>,
* the distance from a glyph to its following glyph might not be the
* glyph's advance, because of kerning or other positioning adjustments.
* <p>
* The bounds is the smallest rectangle that completely contains the
* outline of the glyph. The bounds rectangle is relative to the
* glyph's origin. The left-side bearing is the distance from the glyph
* origin to the left of its bounds rectangle. If the left-side bearing is
* negative, part of the glyph is drawn to the left of its origin. The
* right-side bearing is the distance from the right side of the bounds
* rectangle to the next glyph origin (the origin plus the advance). If
* negative, part of the glyph is drawn to the right of the next glyph's
* origin. Note that the bounds does not necessarily enclose all the pixels
* affected when rendering the glyph, because of rasterization and pixel
* adjustment effects.
* <p>
* Although instances of <code>GlyphMetrics</code> can be directly
* constructed, they are almost always obtained from a
* <code>GlyphVector</code>. Once constructed, <code>GlyphMetrics</code>
* objects are immutable.
* <p>
* <strong>Example</strong>:<p>
* Querying a <code>Font</code> for glyph information
* <blockquote><pre>
* Font font = ...;
* int glyphIndex = ...;
* GlyphMetrics metrics = GlyphVector.getGlyphMetrics(glyphIndex);
* int isStandard = metrics.isStandard();
* float glyphAdvance = metrics.getAdvance();
* </pre></blockquote>
* @see java.awt.Font
* @see GlyphVector
*/
public final class GlyphMetrics {
/**
* Indicates whether the metrics are for a horizontal or vertical baseline.
*/
private boolean horizontal;
/**
* The x-component of the advance.
*/
private float advanceX;
/**
* The y-component of the advance.
*/
private float advanceY;
/**
* The bounds of the associated glyph.
*/
private Rectangle2D.Float bounds;
/**
* Additional information about the glyph encoded as a byte.
*/
private byte glyphType;
/**
* Indicates a glyph that represents a single standard
* character.
*/
public static final byte STANDARD = 0;
/**
* Indicates a glyph that represents multiple characters
* as a ligature, for example 'fi' or 'ffi'. It is followed by
* filler glyphs for the remaining characters. Filler and combining
* glyphs can be intermixed to control positioning of accent marks
* on the logically preceeding ligature.
*/
public static final byte LIGATURE = 1;
/**
* Indicates a glyph that represents a combining character,
* such as an umlaut. There is no caret position between this glyph
* and the preceeding glyph.
*/
public static final byte COMBINING = 2;
/**
* Indicates a glyph with no corresponding character in the
* backing store. The glyph is associated with the character
* represented by the logicaly preceeding non-component glyph. This
* is used for kashida justification or other visual modifications to
* existing glyphs. There is no caret position between this glyph
* and the preceeding glyph.
*/
public static final byte COMPONENT = 3;
/**
* Indicates a glyph with no visual representation. It can
* be added to the other code values to indicate an invisible glyph.
*/
public static final byte WHITESPACE = 4;
/**
* Constructs a <code>GlyphMetrics</code> object.
* @param advance the advance width of the glyph
* @param bounds the black box bounds of the glyph
* @param glyphType the type of the glyph
*/
public GlyphMetrics(float advance, Rectangle2D bounds, byte glyphType) {
this.horizontal = true;
this.advanceX = advance;
this.advanceY = 0;
this.bounds = new Rectangle2D.Float();
this.bounds.setRect(bounds);
this.glyphType = glyphType;
}
/**
* Constructs a <code>GlyphMetrics</code> object.
* @param horizontal if true, metrics are for a horizontal baseline,
* otherwise they are for a vertical baseline
* @param advanceX the X-component of the glyph's advance
* @param advanceY the Y-component of the glyph's advance
* @param bounds the visual bounds of the glyph
* @param glyphType the type of the glyph
*/
public GlyphMetrics(boolean horizontal, float advanceX, float advanceY,
Rectangle2D bounds, byte glyphType) {
this.horizontal = horizontal;
this.advanceX = advanceX;
this.advanceY = advanceY;
this.bounds = new Rectangle2D.Float();
this.bounds.setRect(bounds);
this.glyphType = glyphType;
}
/**
* Returns the advance of the glyph along the baseline (either
* horizontal or vertical).
* @return the advance of the glyph
*/
public float getAdvance() {
return horizontal ? advanceX : advanceY;
}
/**
* Returns the x-component of the advance of the glyph.
* @return the x-component of the advance of the glyph
*/
public float getAdvanceX() {
return advanceX;
}
/**
* Returns the y-component of the advance of the glyph.
* @return the y-component of the advance of the glyph
*/
public float getAdvanceY() {
return advanceY;
}
/**
* Returns the bounds of the glyph. This is the bounding box of the glyph outline.
* Because of rasterization and pixel alignment effects, it does not necessarily
* enclose the pixels that are affected when rendering the glyph.
* @return a {@link Rectangle2D} that is the bounds of the glyph.
*/
public Rectangle2D getBounds2D() {
return new Rectangle2D.Float(bounds.x, bounds.y, bounds.width, bounds.height);
}
/**
* Returns the left (top) side bearing of the glyph.
* <p>
* This is the distance from 0, 0 to the left (top) of the glyph
* bounds. If the bounds of the glyph is to the left of (above) the
* origin, the LSB is negative.
* @return the left side bearing of the glyph.
*/
public float getLSB() {
return horizontal ? bounds.x : bounds.y;
}
/**
* Returns the right (bottom) side bearing of the glyph.
* <p>
* This is the distance from the right (bottom) of the glyph bounds to
* the advance. If the bounds of the glyph is to the right of (below)
* the advance, the RSB is negative.
* @return the right side bearing of the glyph.
*/
public float getRSB() {
return horizontal ?
advanceX - bounds.x - bounds.width :
advanceY - bounds.y - bounds.height;
}
/**
* Returns the raw glyph type code.
* @return the raw glyph type code.
*/
public int getType() {
return glyphType;
}
/**
* Returns <code>true</code> if this is a standard glyph.
* @return <code>true</code> if this is a standard glyph;
* <code>false</code> otherwise.
*/
public boolean isStandard() {
return (glyphType & 0x3) == STANDARD;
}
/**
* Returns <code>true</code> if this is a ligature glyph.
* @return <code>true</code> if this is a ligature glyph;
* <code>false</code> otherwise.
*/
public boolean isLigature() {
return (glyphType & 0x3) == LIGATURE;
}
/**
* Returns <code>true</code> if this is a combining glyph.
* @return <code>true</code> if this is a combining glyph;
* <code>false</code> otherwise.
*/
public boolean isCombining() {
return (glyphType & 0x3) == COMBINING;
}
/**
* Returns <code>true</code> if this is a component glyph.
* @return <code>true</code> if this is a component glyph;
* <code>false</code> otherwise.
*/
public boolean isComponent() {
return (glyphType & 0x3) == COMPONENT;
}
/**
* Returns <code>true</code> if this is a whitespace glyph.
* @return <code>true</code> if this is a whitespace glyph;
* <code>false</code> otherwise.
*/
public boolean isWhitespace() {
return (glyphType & 0x4) == WHITESPACE;
}
}
|
