java.awt.font: public final class: GlyphMetrics

java.awt.font
public final class: GlyphMetrics [javadoc | source]

java.lang.Object
   java.awt.font.GlyphMetrics

The GlyphMetrics 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. GlyphMetrics instances are produced by Font and are applicable to a specific glyph in a particular Font.

Glyphs are either STANDARD, LIGATURE, COMBINING, or COMPONENT.

STANDARD glyphs are commonly used to represent single characters.
LIGATURE glyphs are used to represent sequences of characters.
COMPONENT glyphs in a GlyphVector do not correspond to a particular character in a text model. Instead, COMPONENT glyphs are added for typographical reasons, such as Arabic justification.
COMBINING glyphs embellish STANDARD or LIGATURE glyphs, such as accent marks. Carets do not appear before COMBINING glyphs.

Other metrics available through GlyphMetrics are the components of the advance, the visual bounds, and the left and right side bearings.

Glyphs for a rotated font, or obtained from a GlyphVector 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.

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 GlyphVector, the distance from a glyph to its following glyph might not be the glyph's advance, because of kerning or other positioning adjustments.

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.

Although instances of GlyphMetrics can be directly constructed, they are almost always obtained from a GlyphVector. Once constructed, GlyphMetrics objects are immutable.

Example:

Querying a Font for glyph information

Font font = ...;
int glyphIndex = ...;
GlyphMetrics metrics = GlyphVector.getGlyphMetrics(glyphIndex);
int isStandard = metrics.isStandard();
float glyphAdvance = metrics.getAdvance();

Also see:

java.awt.Font

GlyphVector

Field Summary
public static final byte	STANDARD	Indicates a glyph that represents a single standard character.
public static final byte	LIGATURE	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	COMBINING	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	COMPONENT	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	WHITESPACE	Indicates a glyph with no visual representation. It can be added to the other code values to indicate an invisible glyph.

Constructor:

Constructor:
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 `GlyphMetrics` object. Parameters: `advance` - the advance width of the glyph `bounds` - the black box bounds of the glyph `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; } Constructs a `GlyphMetrics` object. Parameters: `horizontal` - if true, metrics are for a horizontal baseline, otherwise they are for a vertical baseline `advanceX` - the X-component of the glyph's advance `advanceY` - the Y-component of the glyph's advance `bounds` - the visual bounds of the glyph `glyphType` - the type of the glyph since: `1.4` -

 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;
}

GlyphMetrics

Parameters:

advance - the advance width of the glyph

bounds - the black box bounds of the glyph

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;
}

GlyphMetrics

Parameters:

horizontal - if true, metrics are for a horizontal baseline, otherwise they are for a vertical baseline

advanceX - the X-component of the glyph's advance

advanceY - the Y-component of the glyph's advance

bounds - the visual bounds of the glyph

glyphType - the type of the glyph

since: 1.4 -

Method from java.awt.font.GlyphMetrics Summary:
getAdvance, getAdvanceX, getAdvanceY, getBounds2D, getLSB, getRSB, getType, isCombining, isComponent, isLigature, isStandard, isWhitespace

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.awt.font.GlyphMetrics Detail:
public float getAdvance() { return horizontal ? advanceX : advanceY; } Returns the advance of the glyph along the baseline (either horizontal or vertical).
public float getAdvanceX() { return advanceX; } Returns the x-component of the advance of the glyph.
public float getAdvanceY() { return advanceY; } Returns the y-component of the advance of the glyph.
public Rectangle2D getBounds2D() { return new Rectangle2D.Float(bounds.x, bounds.y, bounds.width, bounds.height); } 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.
public float getLSB() { return horizontal ? bounds.x : bounds.y; } Returns the left (top) side bearing of the glyph. 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.
public float getRSB() { return horizontal ? advanceX - bounds.x - bounds.width : advanceY - bounds.y - bounds.height; } Returns the right (bottom) side bearing of the glyph. 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.
public int getType() { return glyphType; } Returns the raw glyph type code.
public boolean isCombining() { return (glyphType & 0x3) == COMBINING; } Returns `true` if this is a combining glyph.
public boolean isComponent() { return (glyphType & 0x3) == COMPONENT; } Returns `true` if this is a component glyph.
public boolean isLigature() { return (glyphType & 0x3) == LIGATURE; } Returns `true` if this is a ligature glyph.
public boolean isStandard() { return (glyphType & 0x3) == STANDARD; } Returns `true` if this is a standard glyph.
public boolean isWhitespace() { return (glyphType & 0x4) == WHITESPACE; } Returns `true` if this is a whitespace glyph.

Method from java.awt.font.GlyphMetrics Detail:

 public float getAdvance() {
        return horizontal ? advanceX : advanceY;
}

Returns the advance of the glyph along the baseline (either horizontal or vertical).

 public float getAdvanceX() {
        return advanceX;
}

Returns the x-component of the advance of the glyph.

 public float getAdvanceY() {
        return advanceY;
}

Returns the y-component of the advance of the glyph.

 public Rectangle2D getBounds2D() {
        return new Rectangle2D.Float(bounds.x, bounds.y, bounds.width, bounds.height);
}

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.

 public float getLSB() {
        return horizontal ? bounds.x : bounds.y;
}

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.

 public float getRSB() {
        return horizontal ?
            advanceX - bounds.x - bounds.width :
            advanceY - bounds.y - bounds.height;
}

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.

 public int getType() {
        return glyphType;
}

Returns the raw glyph type code.

 public boolean isCombining() {
        return (glyphType & 0x3) == COMBINING;
}

true

 public boolean isComponent() {
        return (glyphType & 0x3) == COMPONENT;
}

true

 public boolean isLigature() {
        return (glyphType & 0x3) == LIGATURE;
}

true

 public boolean isStandard() {
        return (glyphType & 0x3) == STANDARD;
}

true

 public boolean isWhitespace() {
        return (glyphType & 0x4) == WHITESPACE;
}

true