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public  abstract  class  java.awt.FontMetrics
    extends  java.lang.Object  (I-§1.12)
{
        // Fields
    protected Font font;	§1.18.1

        // Constructors
    protected FontMetrics(Font  font);	§1.18.2

        // Methods
    public int bytesWidth(byte  data[], int  off, int len);	§1.18.3
    public int charsWidth(char  data[], int  off, int len);	§1.18.4
    public int charWidth(char  ch);	§1.18.5
    public int charWidth(int  ch);	§1.18.6
    public int getAscent();	§1.18.7
    public int getDescent();	§1.18.8
    public Font getFont();	§1.18.9
    public int getHeight();	§1.18.10
    public int getLeading();	§1.18.11
    public int getMaxAdvance();	§1.18.12
    public int getMaxAscent();	§1.18.13
    public int getMaxDescent();	§1.18.14
    public int[] getWidths();	§1.18.15
    public int stringWidth(String  str);	§1.18.16
    public String toString();	§1.18.17
}

When an application asks the AWT to place a character at the position , the character is placed so that its reference point (shown as the dot in the picture on the right) is put at that position. The reference point specifies a horizontal line called the baseline of the character. In normal printing, the baselines of the characters should align. In addition, every character in a font has an ascent, a descent, and an advance width. The ascent is the amount by which the character ascends above the baseline. The descent is the amount by which the character descends below the baseline.

The advance width indicates the position at which AWT should place the next character. If the current character is placed with its reference point at the position , and the character's advance width is , then the following character is placed with its reference point at the position . The advance width is often the same as the width of character's bounding box, but need not be so. It particular, slanted and italic fonts often have characters whose top-right corner extends slightly beyond the advance width.

An array of characters or a string can also have an ascent, a descent, and an advance width. The ascent of the array is the maximum ascent of any character in the array. The descent is the maximum descent of any character in the array. The advance width is the sum of the advance widths of each of the characters in the array.

The default implementations of these methods are inefficient; they are usually overridden with more efficient toolkit-specific implementations.

The actual font.

See Also:

getFont (II-§1.18.9).

Creates a new FontMetrics object for finding out height and width information about the specified font and specific character glyphs in that font.

Parameters:

font - the font

See Also:

Font (II-§1.17).

Parameters:

data - an array of characters

off - the start offset of the data

len - the number of bytes to be measured

Returns:

the advance width of the subarray of the specified byte array in the font described by this font metric.

See Also:

stringWidth (II-§1.18.16)
charsWidth (II-§1.18.4).

Parameters:

data - an array of characters

off - the start offset of the data

len - the number of bytes measured

Returns:

the advance width of the subarray of the specified char array in the font described by this font metric.

See Also:

stringWidth (II-§1.18.16)
bytesWidth (II-§1.18.3).

Parameters:

ch - a char

Returns:

the advance width of the specified char in the font described by this font metric.

See Also:

stringWidth (II-§1.18.16).

Parameters:

ch - a char

Returns:

the advance width of the specified character in the font described by this font metric.

See Also:

stringWidth (II-§1.18.16).

Determines the font ascent of the font described by this font metric. The font ascent is the distance from the base line to the top of most alphanumeric characters. Some characters in the font may extend above this distance..

Returns:

the font ascent of the font.

See Also:

getMaxAscent (II-§1.18.13).

Determines the font descent of the font described this font metric. The font descent is the distance from the base line to the bottom of most alphanumeric characters. Some characters in the font may extend below this distance.

Returns:

the font descent of the font.

See Also:

getMaxDescent (II-§1.18.14).

Returns:

the font described by this font metric.

Determines the standard height of a line of text in the font described by this font metric. This standard height is the distance between the baseline of adjacent lines of text. It is computed as the sum

getLeading() + getAscent() + getDescent()

There is no guarantee that lines of text spaced at this distance must be disjoint; such lines may overlap if some characters overshoot either the standard ascent or the standard descent.

Returns:

the standard height of the font.

Determines the standard leading of the font described by this font metric. The standard leading (inter-line spacing) is the logical amount of space to be reserved between the descent of one line of text and the ascent of the next line. The height metric is calculated to include this extra space.

Returns:

the standard leading of the font.

Returns:

the maximum advance width of any character in the font, or -1 if the maximum advance is not known.

Determines the maximum ascent of the font described by this font metric. No character extends further above the baseline than this height.

Returns:

the maximum ascent of any character in the font.

See Also:

getAscent (II-§1.18.7).

Determines the maximum descent of the font described by this font metric. No character extends further below the baseline than this height.

Returns:

the maximum descent of any character in the font.

See Also:

getDescent (II-§1.18.8).

Returns:

any array giving the advance widths of the first 256 characters in the font described by this font metric.

Parameters:

str - a string

Returns:

the advance width of the specified string in the font described by this font metric.

See Also:

charsWidth (II-§1.18.4)
bytesWidth (II-§1.18.3).

Returns:

a string representation of this font metric.

Overrides:

toString in class Object (I-§1.12.9).

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