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.

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();
 
Constructs a GlyphMetrics object.
Parameters
advancethe advance width of the glyph
boundsthe black box bounds of the glyph
glyphTypethe type of the glyph
Constructs a GlyphMetrics object.
Parameters
horizontalif true, metrics are for a horizontal baseline, otherwise they are for a vertical baseline
advanceXthe X-component of the glyph's advance
advanceYthe Y-component of the glyph's advance
boundsthe visual bounds of the glyph
glyphTypethe type of the glyph
Indicates a glyph that represents a combining character, such as an umlaut. There is no caret position between this glyph and the preceeding glyph.
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.
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.
Indicates a glyph that represents a single standard character.
Indicates a glyph with no visual representation. It can be added to the other code values to indicate an invisible glyph.
Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
objthe reference object with which to compare.
Return
true if this object is the same as the obj argument; false otherwise.
Returns the advance of the glyph along the baseline (either horizontal or vertical).
Return
the advance of the glyph
Returns the x-component of the advance of the glyph.
Return
the x-component of the advance of the glyph
Returns the y-component of the advance of the glyph.
Return
the y-component of the advance of the glyph
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.
Returns the runtime class of an object. That Class object is the object that is locked by static synchronized methods of the represented class.
Return
The java.lang.Class object that represents the runtime class of the object. The result is of type {@code Class} where X is the erasure of the static type of the expression on which getClass is called.
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.

Return
the left side bearing of the glyph.
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.

Return
the right side bearing of the glyph.
Returns the raw glyph type code.
Return
the raw glyph type code.
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

Return
a hash code value for this object.
Returns true if this is a combining glyph.
Return
true if this is a combining glyph; false otherwise.
Returns true if this is a component glyph.
Return
true if this is a component glyph; false otherwise.
Returns true if this is a ligature glyph.
Return
true if this is a ligature glyph; false otherwise.
Returns true if this is a standard glyph.
Return
true if this is a standard glyph; false otherwise.
Returns true if this is a whitespace glyph.
Return
true if this is a whitespace glyph; false otherwise.
Wakes up a single thread that is waiting on this object's monitor. If any threads are waiting on this object, one of them is chosen to be awakened. The choice is arbitrary and occurs at the discretion of the implementation. A thread waits on an object's monitor by calling one of the wait methods.

The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods.

The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 
Return
a string representation of the object.
Causes current thread to wait until another thread invokes the method or the method for this object. In other words, this method behaves exactly as if it simply performs the call wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait();
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Throws
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.

The current thread must own this object's monitor.

This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:

  • Some other thread invokes the notify method for this object and thread T happens to be arbitrarily chosen as the thread to be awakened.
  • Some other thread invokes the notifyAll method for this object.
  • Some other thread interrupts thread T.
  • The specified amount of real time has elapsed, more or less. If timeout is zero, however, then real time is not taken into consideration and the thread simply waits until notified.
The thread T is then removed from the wait set for this object and re-enabled for thread scheduling. It then competes in the usual manner with other threads for the right to synchronize on the object; once it has gained control of the object, all its synchronization claims on the object are restored to the status quo ante - that is, to the situation as of the time that the wait method was invoked. Thread T then returns from the invocation of the wait method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked.

A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout);
         ... // Perform action appropriate to condition
     }
 
(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).

If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.

Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Parameters
timeoutthe maximum time to wait in milliseconds.
Throws
IllegalArgumentExceptionif the value of timeout is negative.
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by:

 1000000*timeout+nanos

In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:

  • Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method.
  • The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed.

The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout, nanos);
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Parameters
timeoutthe maximum time to wait in milliseconds.
nanosadditional time, in nanoseconds range 0-999999.
Throws
IllegalArgumentExceptionif the value of timeout is negative or the value of nanos is not in the range 0-999999.
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.