Java Component.getFontMetrics方法代码示例

import java.awt.Component; //导入方法依赖的package包/类
/**
 * Reinitialize the insets parameter with this Border's current Insets.
 * @param c the component for which this border insets value applies
 * @param insets the object to be reinitialized
 */
public Insets getBorderInsets(Component c, Insets insets) {
    if (!(c instanceof JPopupMenu)) {
        return insets;
    }
    FontMetrics fm;
    int         descent = 0;
    int         ascent = 16;

    String title = ((JPopupMenu)c).getLabel();
    if (title == null) {
        insets.left = insets.top = insets.right = insets.bottom = 0;
        return insets;
    }

    fm = c.getFontMetrics(font);

    if(fm != null) {
        descent = fm.getDescent();
        ascent = fm.getAscent();
    }

    insets.top += ascent + descent + TEXT_SPACING + GROOVE_HEIGHT;
    return insets;
}
 

import java.awt.Component; //导入方法依赖的package包/类
/** Get the font-metrics for the given font.
* @param font font for which the metrics is being retrieved.
* @param c component that is used to retrieve the metrics in case it's
*   not yet in the cache.
*/
public static synchronized FontMetrics getFontMetrics(Font f, Component c) {
    Object fm = font2FM.get(f);
    if (fm == null) {
        fm = c.getFontMetrics(f);
        font2FM.put(f, fm);
    }
    return (FontMetrics)fm;
}
 

import java.awt.Component; //导入方法依赖的package包/类
/**
    * Return true if this font is fixed width.
    * Only the first 256 characters are considered.
    * @param font
    * @return true if this font is fixed width.
    */
   private static boolean isFixedWidth(Component context, Font font) {
FontMetrics metrics = context.getFontMetrics(font);
int[] widths = metrics.getWidths();
int Swidth = widths[0];
for (int cx = 1; cx < widths.length; cx++) {
    int width = widths[cx];
    if (width == 0) {
	continue;
    } else if (Swidth != width) {
	return false;
    }
}
return true;
   }
 

import java.awt.Component; //导入方法依赖的package包/类
final void updateMetrics() {
	Component host = getContainer();
	Font f = host.getFont();
	metrics = host.getFontMetrics(f); // Metrics for the default font.
	tabSize = getTabSize() * metrics.charWidth('m');
}