FileDocCategorySizeDatePackage
GradientFormatter.javaAPI DocApache Lucene 2.1.08405Wed Feb 14 10:46:22 GMT 2007org.apache.lucene.search.highlight

GradientFormatter

public class GradientFormatter extends Object implements Formatter
Formats text with different color intensity depending on the score of the term.
author
maharwood

Fields Summary
private float
maxScore
int
fgRMin
int
fgGMin
int
fgBMin
int
fgRMax
int
fgGMax
int
fgBMax
protected boolean
highlightForeground
int
bgRMin
int
bgGMin
int
bgBMin
int
bgRMax
int
bgGMax
int
bgBMax
protected boolean
highlightBackground
private static char[]
hexDigits
Constructors Summary
public GradientFormatter(float maxScore, String minForegroundColor, String maxForegroundColor, String minBackgroundColor, String maxBackgroundColor)
Sets the color range for the IDF scores

param
maxScore The score (and above) displayed as maxColor (See QueryScorer.getMaxWeight which can be used to callibrate scoring scale)
param
minForegroundColor The hex color used for representing IDF scores of zero eg #FFFFFF (white) or null if no foreground color required
param
maxForegroundColor The largest hex color used for representing IDF scores eg #000000 (black) or null if no foreground color required
param
minBackgroundColor The hex color used for representing IDF scores of zero eg #FFFFFF (white) or null if no background color required
param
maxBackgroundColor The largest hex color used for representing IDF scores eg #000000 (black) or null if no background color required

        highlightForeground = (minForegroundColor != null)
                && (maxForegroundColor != null);
        if (highlightForeground)
        {
            if (minForegroundColor.length() != 7)
            {
                throw new IllegalArgumentException(
                        "minForegroundColor is not 7 bytes long eg a hex "
                                + "RGB value such as #FFFFFF");
            }
            if (maxForegroundColor.length() != 7)
            {
                throw new IllegalArgumentException(
                        "minForegroundColor is not 7 bytes long eg a hex "
                                + "RGB value such as #FFFFFF");
            }
            fgRMin = hexToInt(minForegroundColor.substring(1, 3));
            fgGMin = hexToInt(minForegroundColor.substring(3, 5));
            fgBMin = hexToInt(minForegroundColor.substring(5, 7));

            fgRMax = hexToInt(maxForegroundColor.substring(1, 3));
            fgGMax = hexToInt(maxForegroundColor.substring(3, 5));
            fgBMax = hexToInt(maxForegroundColor.substring(5, 7));
        }

        highlightBackground = (minBackgroundColor != null)
                && (maxBackgroundColor != null);
        if (highlightBackground)
        {
            if (minBackgroundColor.length() != 7)
            {
                throw new IllegalArgumentException(
                        "minBackgroundColor is not 7 bytes long eg a hex "
                                + "RGB value such as #FFFFFF");
            }
            if (maxBackgroundColor.length() != 7)
            {
                throw new IllegalArgumentException(
                        "minBackgroundColor is not 7 bytes long eg a hex "
                                + "RGB value such as #FFFFFF");
            }
            bgRMin = hexToInt(minBackgroundColor.substring(1, 3));
            bgGMin = hexToInt(minBackgroundColor.substring(3, 5));
            bgBMin = hexToInt(minBackgroundColor.substring(5, 7));

            bgRMax = hexToInt(maxBackgroundColor.substring(1, 3));
            bgGMax = hexToInt(maxBackgroundColor.substring(3, 5));
            bgBMax = hexToInt(maxBackgroundColor.substring(5, 7));
        }
        //        this.corpusReader = corpusReader;
        this.maxScore = maxScore;
        //        totalNumDocs = corpusReader.numDocs();
Methods Summary
protected java.lang.StringgetBackgroundColorString(float score)

        int rVal = getColorVal(bgRMin, bgRMax, score);
        int gVal = getColorVal(bgGMin, bgGMax, score);
        int bVal = getColorVal(bgBMin, bgBMax, score);
        StringBuffer sb = new StringBuffer();
        sb.append("#");
        sb.append(intToHex(rVal));
        sb.append(intToHex(gVal));
        sb.append(intToHex(bVal));
        return sb.toString();
private intgetColorVal(int colorMin, int colorMax, float score)

        if (colorMin == colorMax)
        {
            return colorMin;
        }
        float scale = Math.abs(colorMin - colorMax);
        float relScorePercent = Math.min(maxScore, score) / maxScore;
        float colScore = scale * relScorePercent;
        return Math.min(colorMin, colorMax) + (int) colScore;
protected java.lang.StringgetForegroundColorString(float score)

        int rVal = getColorVal(fgRMin, fgRMax, score);
        int gVal = getColorVal(fgGMin, fgGMax, score);
        int bVal = getColorVal(fgBMin, fgBMax, score);
        StringBuffer sb = new StringBuffer();
        sb.append("#");
        sb.append(intToHex(rVal));
        sb.append(intToHex(gVal));
        sb.append(intToHex(bVal));
        return sb.toString();
public static final inthexToInt(java.lang.String hex)
Converts a hex string into an int. Integer.parseInt(hex, 16) assumes the input is nonnegative unless there is a preceding minus sign. This method reads the input as twos complement instead, so if the input is 8 bytes long, it will correctly restore a negative int produced by Integer.toHexString() but not neccesarily one produced by Integer.toString(x,16) since that method will produce a string like '-FF' for negative integer values.

param
hex A string in capital or lower case hex, of no more then 16 characters.
throws
NumberFormatException if the string is more than 16 characters long, or if any character is not in the set [0-9a-fA-f]

        int len = hex.length();
        if (len > 16)
            throw new NumberFormatException();

        int l = 0;
        for (int i = 0; i < len; i++)
        {
            l <<= 4;
            int c = Character.digit(hex.charAt(i), 16);
            if (c < 0)
                throw new NumberFormatException();
            l |= c;
        }
        return l;
public java.lang.StringhighlightTerm(java.lang.String originalText, TokenGroup tokenGroup)

        if (tokenGroup.getTotalScore() == 0)
            return originalText;
        float score = tokenGroup.getTotalScore();
        if (score == 0)
        {
            return originalText;
        }
        StringBuffer sb = new StringBuffer();
        sb.append("<font ");
        if (highlightForeground)
        {
            sb.append("color=\"");
            sb.append(getForegroundColorString(score));
            sb.append("\" ");
        }
        if (highlightBackground)
        {
            sb.append("bgcolor=\"");
            sb.append(getBackgroundColorString(score));
            sb.append("\" ");
        }
        sb.append(">");
        sb.append(originalText);
        sb.append("</font>");
        return sb.toString();
private static java.lang.StringintToHex(int i)


        
    
        return "" + hexDigits[(i & 0xF0) >> 4] + hexDigits[i & 0x0F];