VerticalMarginSpan.java

package net.nightwhistler.htmlspanner.spans;

import android.graphics.Paint;
import android.text.style.LineHeightSpan;
import android.util.Log;

/**
 * Span used to implement the top- and bottom margin of blocks.
 *
 * Generally this is placed on a blank line, so that the height of
 * that line can be changed to create a margin.
 *
 * @author Alex Kuiper
 */
public class VerticalMarginSpan implements LineHeightSpan {

    private final Float factor;
    private final Integer absolute;

    public VerticalMarginSpan(Float margin) {
        this.factor = margin;
        this.absolute = null;
    }

    public VerticalMarginSpan(Integer value) {
        this.absolute = value;
        this.factor = null;
    }

    @Override
    public void chooseHeight(CharSequence text, int start, int end, int spanstartv, int v,
                             Paint.FontMetricsInt fm) {

        int height = Math.abs( fm.descent - fm.ascent );

        if ( factor != null ) {
            height = (int) (height * factor);
        } else if ( absolute != null ) {
            height = absolute;
        }

        fm.descent = fm.ascent + height;

    }
}