How to use

getLeading

method

in

java.awt.font.LineMetrics

/**
 * Vertical centering is not trivial, because visually we want centering on characters such as
 * a,m,e, and not centering on d,g whose center is affected by the full ascent or the full
 * descent. This method tries to computes the y anchor taking into account those.
 */
public double getLinePlacementYAnchor() {
  TextStyle2D textStyle = getLabel().getTextStyle();
  LineMetrics lm =
      textStyle
          .getFont()
          .getLineMetrics(textStyle.getLabel(), graphics.getFontRenderContext());
  // gracefully handle font size = 0
  if (lm.getHeight() > 0) {
    return (Math.abs(lm.getStrikethroughOffset()) + lm.getDescent() + lm.getLeading())
        / lm.getHeight();
  } else {
    return 0;
  }
}

public String toString() {
  StringBuffer buf = new StringBuffer();
  buf.append("{text=");
  for (int i = 0; i < length(); i++) {
    buf.append(aStrings[i].getIterator().current());
  }
  final String RS = "\n\t";
  buf.append(RS);
  for (int i = 0; i < length(); i++) {
    buf.append(bounds[i].toString());
    final String FS = " ";
    final LineMetrics m = metrics[i];
    // height = ascent + descent + leading
    buf.append(" ascent=").append(m.getAscent()).append(FS);
    buf.append("descent=").append(m.getDescent()).append(FS);
    buf.append("leading=").append(m.getLeading()).append(FS);
    buf.append(RS);
  }
  buf.append("}");
  return buf.toString();
}

@Override
public int getPreferredHeight(int width) {
  int preferredHeight = thickness;
  Separator separator = (Separator)getComponent();
  String heading = separator.getHeading();
  if (heading != null
    && heading.length() > 0) {
    FontRenderContext fontRenderContext = Platform.getFontRenderContext();
    LineMetrics lm = font.getLineMetrics(heading, fontRenderContext);
    preferredHeight = Math.max((int)Math.ceil(lm.getAscent() + lm.getDescent()
      + lm.getLeading()), preferredHeight);
  }
  preferredHeight += (padding.top + padding.bottom);
  return preferredHeight;
}

@Override
public int getPreferredHeight(int width) {
  int preferredHeight = thickness;
  Separator separator = (Separator)getComponent();
  String heading = separator.getHeading();
  if (heading != null
    && heading.length() > 0) {
    FontRenderContext fontRenderContext = Platform.getFontRenderContext();
    LineMetrics lm = font.getLineMetrics(heading, fontRenderContext);
    preferredHeight = Math.max((int)Math.ceil(lm.getAscent() + lm.getDescent()
      + lm.getLeading()), preferredHeight);
  }
  preferredHeight += (padding.top + padding.bottom);
  return preferredHeight;
}

/**
 * Calculates the vertical offset between the baseline and the specified 
 * text anchor.
 * 
 * @param g2  the graphics device.
 * @param anchor  the anchor.
 * 
 * @return the offset.
 */
public float calculateBaselineOffset(final Graphics2D g2, 
                   final TextAnchor anchor) {
  float result = 0.0f;
  final FontMetrics fm = g2.getFontMetrics(this.font);
  final LineMetrics lm = fm.getLineMetrics("ABCxyz", g2);
  if (anchor == TextAnchor.TOP_LEFT || anchor == TextAnchor.TOP_CENTER
                   || anchor == TextAnchor.TOP_RIGHT) {
    result = lm.getAscent();
  }
  else if (anchor == TextAnchor.BOTTOM_LEFT 
      || anchor == TextAnchor.BOTTOM_CENTER
      || anchor == TextAnchor.BOTTOM_RIGHT) {
    result = -lm.getDescent() - lm.getLeading();
  }
  return result;                                             
}
 

/**
 * Calculates the vertical offset between the baseline and the specified 
 * text anchor.
 * 
 * @param g2  the graphics device.
 * @param anchor  the anchor.
 * 
 * @return the offset.
 */
public float calculateBaselineOffset(final Graphics2D g2, 
                   final TextAnchor anchor) {
  float result = 0.0f;
  final FontMetrics fm = g2.getFontMetrics(this.font);
  final LineMetrics lm = fm.getLineMetrics("ABCxyz", g2);
  if (anchor == TextAnchor.TOP_LEFT || anchor == TextAnchor.TOP_CENTER
                   || anchor == TextAnchor.TOP_RIGHT) {
    result = lm.getAscent();
  }
  else if (anchor == TextAnchor.BOTTOM_LEFT 
      || anchor == TextAnchor.BOTTOM_CENTER
      || anchor == TextAnchor.BOTTOM_RIGHT) {
    result = -lm.getDescent() - lm.getLeading();
  }
  return result;                                             
}
 

@Override
public Dimensions getPreferredSize() {
  int preferredWidth = 0;
  int preferredHeight = thickness;
  Separator separator = (Separator)getComponent();
  String heading = separator.getHeading();
  if (heading != null
    && heading.length() > 0) {
    FontRenderContext fontRenderContext = Platform.getFontRenderContext();
    Rectangle2D headingBounds = font.getStringBounds(heading, fontRenderContext);
    LineMetrics lm = font.getLineMetrics(heading, fontRenderContext);
    preferredWidth = (int)Math.ceil(headingBounds.getWidth());
    preferredHeight = Math.max((int)Math.ceil(lm.getAscent() + lm.getDescent()
      + lm.getLeading()), preferredHeight);
  }
  preferredHeight += (padding.top + padding.bottom);
  preferredWidth += (padding.left + padding.right);
  return new Dimensions(preferredWidth, preferredHeight);
}

float ah = ch - insets.top - insets.bottom;
float th = lm.getAscent() + lm.getDescent() + lm.getLeading();

@Override
public Dimensions getPreferredSize() {
  int preferredWidth = 0;
  int preferredHeight = thickness;
  Separator separator = (Separator)getComponent();
  String heading = separator.getHeading();
  if (heading != null
    && heading.length() > 0) {
    FontRenderContext fontRenderContext = Platform.getFontRenderContext();
    Rectangle2D headingBounds = font.getStringBounds(heading, fontRenderContext);
    LineMetrics lm = font.getLineMetrics(heading, fontRenderContext);
    preferredWidth = (int)Math.ceil(headingBounds.getWidth());
    preferredHeight = Math.max((int)Math.ceil(lm.getAscent() + lm.getDescent()
      + lm.getLeading()), preferredHeight);
  }
  preferredHeight += (padding.top + padding.bottom);
  preferredWidth += (padding.left + padding.right);
  return new Dimensions(preferredWidth, preferredHeight);
}

private void writeFootline(AffineTransform pageTrafo) throws IOException {
  if (footerText != null) {
    LineMetrics metrics = footerFont.getLineMetrics("mM",
        getFontRenderContext());
    double y = getHeight() + footerFont.getSize2D() / 2;
    writeLine(pageTrafo, footerFont, footerText, y
        + metrics.getLeading(), TEXT_TOP, y, footerUnderline);
  }
}

private void writeHeadline(AffineTransform pageTrafo) throws IOException {
  if (headerText != null) {
    LineMetrics metrics = headerFont.getLineMetrics("mM",
        getFontRenderContext());
    writeLine(pageTrafo, headerFont, headerText, -metrics.getLeading()
        - headerFont.getSize2D() / 2, TEXT_BOTTOM, -headerFont
        .getSize2D() / 2, headerUnderline);
  }
}

/**
 * Vertical centering is not trivial, because visually we want centering on
 * characters such as a,m,e, and not centering on d,g whose center is
 * affected by the full ascent or the full descent. This method tries to
 * computes the y anchor taking into account those.
 */
public double getLinePlacementYAnchor() {
  TextStyle2D textStyle = getLabel().getTextStyle();
  LineMetrics lm = textStyle.getFont().getLineMetrics(textStyle.getLabel(),
      graphics.getFontRenderContext());
  
  // gracefully handle font size = 0
  if(lm.getHeight() > 0)
    return (Math.abs(lm.getStrikethroughOffset()) + lm.getDescent() + lm.getLeading())
        / lm.getHeight();
  else 
    return 0;
}

public JavaFont(String fontName, int fontStyle, int fontSize)
{
 super(fontName, fontStyle, fontSize);
 myFont = UIManager.getCachedJavaFont(fontName, fontStyle, fontSize);
 frc = new java.awt.font.FontRenderContext(null, true, false);
 java.awt.font.LineMetrics metrics = myFont.getLineMetrics("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopwrstuvwxyz0123456789", frc);
 height = metrics.getHeight();
 ascent = metrics.getAscent();
 leading = metrics.getLeading();
 descent = metrics.getDescent();
}
public MetaFont deriveFontSize(int newSize, UIManager uiLoader)

/**
 * Calculates the vertical offset between the baseline and the specified 
 * text anchor.
 * 
 * @param g2  the graphics device.
 * @param anchor  the anchor.
 * 
 * @return the offset.
 */
public float calculateBaselineOffset(Graphics2D g2, TextAnchor anchor) {
  float result = 0.0f;
  FontMetrics fm = g2.getFontMetrics(this.font);
  LineMetrics lm = fm.getLineMetrics("ABCxyz", g2);
  if (anchor.isTop()) {
    result = lm.getAscent();
  }
  else if (anchor.isHalfAscent()) {
    result = lm.getAscent() / 2.0f;
  }
  else if (anchor.isVerticalCenter()) {
    result = lm.getAscent() / 2.0f - lm.getDescent() / 2.0f;
  }
  else if (anchor.isBottom()) {
    result = -lm.getDescent() - lm.getLeading();
  }
  return result;                                             
}

/**
 * Calculates the vertical offset between the baseline and the specified 
 * text anchor.
 * 
 * @param g2  the graphics device.
 * @param anchor  the anchor.
 * 
 * @return the offset.
 */
public float calculateBaselineOffset(Graphics2D g2, TextAnchor anchor) {
  float result = 0.0f;
  final FontMetrics fm = g2.getFontMetrics(this.font);
  final LineMetrics lm = fm.getLineMetrics("ABCxyz", g2);
  if (anchor.isTop()) {
    result = lm.getAscent();
  }
  else if (anchor.isHalfAscent()) {
    result = lm.getAscent() / 2.0f;
  }
  else if (anchor.isVerticalCenter()) {
    result = lm.getAscent() / 2.0f - lm.getDescent() / 2.0f;
  }
  else if (anchor.isBottom()) {
    result = -lm.getDescent() - lm.getLeading();
  }
  return result;                                             
}
 

/**
 * Constructs a GVTLineMetrics object based on the specified line metrics.
 *
 * @param lineMetrics The lineMetrics object that this metrics object will
 * be based upon.
 */
public GVTLineMetrics(LineMetrics lineMetrics) {
  this.ascent = lineMetrics.getAscent();
  this.baselineIndex = lineMetrics.getBaselineIndex();
  this.baselineOffsets = lineMetrics.getBaselineOffsets();
  this.descent = lineMetrics.getDescent();
  this.height = lineMetrics.getHeight();
  this.leading = lineMetrics.getLeading();
  this.numChars = lineMetrics.getNumChars();
  this.strikethroughOffset = lineMetrics.getStrikethroughOffset();
  this.strikethroughThickness = lineMetrics.getStrikethroughThickness();
  this.underlineOffset = lineMetrics.getUnderlineOffset();
  this.underlineThickness = lineMetrics.getUnderlineThickness();
  this.overlineOffset = -this.ascent;
  this.overlineThickness = this.underlineThickness;
}

/**
 * Constructs a GVTLineMetrics object based on the specified line metrics.
 *
 * @param lineMetrics The lineMetrics object that this metrics object will
 * be based upon.
 */
public GVTLineMetrics(LineMetrics lineMetrics) {
  this.ascent = lineMetrics.getAscent();
  this.baselineIndex = lineMetrics.getBaselineIndex();
  this.baselineOffsets = lineMetrics.getBaselineOffsets();
  this.descent = lineMetrics.getDescent();
  this.height = lineMetrics.getHeight();
  this.leading = lineMetrics.getLeading();
  this.numChars = lineMetrics.getNumChars();
  this.strikethroughOffset = lineMetrics.getStrikethroughOffset();
  this.strikethroughThickness = lineMetrics.getStrikethroughThickness();
  this.underlineOffset = lineMetrics.getUnderlineOffset();
  this.underlineThickness = lineMetrics.getUnderlineThickness();
  this.overlineOffset = -this.ascent;
  this.overlineThickness = this.underlineThickness;
}

/**
 * Constructs a GVTLineMetrics object based on the specified line metrics.
 *
 * @param lineMetrics The lineMetrics object that this metrics object will
 * be based upon.
 */
public GVTLineMetrics(LineMetrics lineMetrics) {
  this.ascent = lineMetrics.getAscent();
  this.baselineIndex = lineMetrics.getBaselineIndex();
  this.baselineOffsets = lineMetrics.getBaselineOffsets();
  this.descent = lineMetrics.getDescent();
  this.height = lineMetrics.getHeight();
  this.leading = lineMetrics.getLeading();
  this.numChars = lineMetrics.getNumChars();
  this.strikethroughOffset = lineMetrics.getStrikethroughOffset();
  this.strikethroughThickness = lineMetrics.getStrikethroughThickness();
  this.underlineOffset = lineMetrics.getUnderlineOffset();
  this.underlineThickness = lineMetrics.getUnderlineThickness();
  this.overlineOffset = -this.ascent;
  this.overlineThickness = this.underlineThickness;
}

/**
 * Constructs a GVTLineMetrics object based on the specified line metrics
 * with a scale factor applied.
 *
 * @param lineMetrics The lineMetrics object that this metrics object will
 * be based upon.
 * @param scaleFactor The scale factor to apply to all metrics.
 */
public GVTLineMetrics(LineMetrics lineMetrics, float scaleFactor) {
  this.ascent = lineMetrics.getAscent() * scaleFactor;
  this.baselineIndex = lineMetrics.getBaselineIndex();
  this.baselineOffsets = lineMetrics.getBaselineOffsets();
  for (int i=0; i<baselineOffsets.length; i++) {
    this.baselineOffsets[i] *= scaleFactor;
  }
  this.descent = lineMetrics.getDescent() * scaleFactor;
  this.height = lineMetrics.getHeight() * scaleFactor;
  this.leading = lineMetrics.getLeading();
  this.numChars = lineMetrics.getNumChars();
  this.strikethroughOffset = 
    lineMetrics.getStrikethroughOffset() * scaleFactor;
  this.strikethroughThickness = 
    lineMetrics.getStrikethroughThickness() * scaleFactor;
  this.underlineOffset = lineMetrics.getUnderlineOffset() * scaleFactor;
  this.underlineThickness = 
    lineMetrics.getUnderlineThickness() * scaleFactor;
  this.overlineOffset = -this.ascent;
  this.overlineThickness = this.underlineThickness;
}

/**
 * Constructs a GVTLineMetrics object based on the specified line metrics
 * with a scale factor applied.
 *
 * @param lineMetrics The lineMetrics object that this metrics object will
 * be based upon.
 * @param scaleFactor The scale factor to apply to all metrics.
 */
public GVTLineMetrics(LineMetrics lineMetrics, float scaleFactor) {
  this.ascent = lineMetrics.getAscent() * scaleFactor;
  this.baselineIndex = lineMetrics.getBaselineIndex();
  this.baselineOffsets = lineMetrics.getBaselineOffsets();
  for (int i=0; i<baselineOffsets.length; i++) {
    this.baselineOffsets[i] *= scaleFactor;
  }
  this.descent = lineMetrics.getDescent() * scaleFactor;
  this.height = lineMetrics.getHeight() * scaleFactor;
  this.leading = lineMetrics.getLeading();
  this.numChars = lineMetrics.getNumChars();
  this.strikethroughOffset = 
    lineMetrics.getStrikethroughOffset() * scaleFactor;
  this.strikethroughThickness = 
    lineMetrics.getStrikethroughThickness() * scaleFactor;
  this.underlineOffset = lineMetrics.getUnderlineOffset() * scaleFactor;
  this.underlineThickness = 
    lineMetrics.getUnderlineThickness() * scaleFactor;
  this.overlineOffset = -this.ascent;
  this.overlineThickness = this.underlineThickness;
}