001// License: GPL. For details, see LICENSE file.
002
003package org.openstreetmap.josm.tools;
004
005import java.awt.Color;
006import java.awt.FontMetrics;
007import java.awt.Graphics2D;
008
009/**
010 * Utility class that helps to work with color scale 
011 * for coloring GPX tracks etc.
012 * @since 7319
013 */
014public class ColorScale {
015    private double min, max;
016    private Color noDataColor;
017    private Color belowMinColor;
018    private Color aboveMaxColor;
019    
020    private Color[] colors;
021    private String title = "";
022    private int intervalCount = 5;
023    
024    private ColorScale() {
025        
026    }
027    
028    public static ColorScale createHSBScale(int count) {
029        ColorScale sc = new ColorScale();
030        sc.colors = new Color[count];
031        for (int i = 0; i < count; i++) {
032            sc.colors[i] = Color.getHSBColor(i / 300.0f, 1, 1);
033        }
034        sc.setRange(0, 255);
035        sc.addBounds();
036        return sc;
037    }
038    
039    public static ColorScale createCyclicScale(int count) {
040        ColorScale sc = new ColorScale();
041        //                    red   yellow  green   blue    red
042        int[] h = new int[] { 0,    59,     127,    244,    360};
043        int[] s = new int[] { 100,  84,     99,     100 };
044        int[] b = new int[] { 90,   93,     74,     83 };
045
046        sc.colors = new Color[count];
047        for (int i = 0; i < sc.colors.length; i++) {
048  
049            float angle = 4 - i / 256f * 4;
050            int quadrant = (int) angle;
051            angle -= quadrant;
052            quadrant = Utils.mod(quadrant+1, 4);
053
054            float vh = h[quadrant] * w(angle) + h[quadrant+1] * (1 - w(angle));
055            float vs = s[quadrant] * w(angle) + s[Utils.mod(quadrant+1, 4)] * (1 - w(angle));
056            float vb = b[quadrant] * w(angle) + b[Utils.mod(quadrant+1, 4)] * (1 - w(angle));
057
058            sc.colors[i] = Color.getHSBColor(vh/360f, vs/100f, vb/100f);
059        }
060        sc.setRange(0, 2*Math.PI);
061        sc.addBounds();
062        return sc;
063    }
064    
065    /**
066     * transition function:
067     *  w(0)=1, w(1)=0, 0&lt;=w(x)&lt;=1
068     * @param x number: 0&lt;=x&lt;=1
069     * @return the weighted value
070     */
071    private static float w(float x) {
072        if (x < 0.5)
073            return 1 - 2*x*x;
074        else
075            return 2*(1-x)*(1-x);
076    }
077
078    public void setRange(double min, double max) {
079        this.min = min;
080        this.max = max;
081    }
082    
083    /**
084     * Add standard colors for values below min or above max value
085     */
086    public void addBounds() {
087        aboveMaxColor = colors[colors.length-1];
088        belowMinColor = colors[0];
089    }
090    
091    public final Color getColor(double value) {
092        if (value<min) return belowMinColor;
093        if (value>max) return aboveMaxColor;
094        if (Double.isNaN(value)) return noDataColor;
095        final int n = colors.length;
096        int idx = (int) ((value-min)*colors.length / (max-min));
097        if (idx<colors.length) {
098            return colors[idx];
099        } else {
100            return colors[n-1]; // this happens when value==max
101        }
102        // int hdoplvl =(int) Math.round(colorModeDynamic ? ((hdop-minval)*255/(maxval-minval))
103        //            : (hdop <= 0 ? 0 : hdop * hdopfactor));
104        // int hdopcolor = 255 - (hdoplvl > 255 ? 255 : hdoplvl);
105    }
106    
107    public final Color getColor(Number value) {
108        return (value==null)? noDataColor : getColor(value.doubleValue());
109    }
110
111    public Color getNoDataColor() {
112        
113        return noDataColor;
114    }
115
116    public void setNoDataColor(Color noDataColor) {
117        this.noDataColor = noDataColor;
118    }
119    
120    public ColorScale makeTransparent(int alpha) {
121        for (int i = 0; i < colors.length; i++) {
122            colors[i] = new Color((colors[i].getRGB() & 0xFFFFFF) | ((alpha & 0xFF) << 24), true);
123        }
124        return this;
125    }
126    
127    public ColorScale addTitle(String title) {
128        this.title = title;
129        return this;
130    }
131    
132    public ColorScale setIntervalCount(int intervalCount) {
133        this.intervalCount = intervalCount;
134        return this;
135    }
136    
137    public ColorScale makeReversed() {
138        int n = colors.length;
139        Color tmp;
140        for (int i=0; i<n/2; i++) {
141            tmp = colors[i];
142            colors[i] = colors[n-1-i];
143            colors[n-1-i] = tmp;
144        }
145        tmp = belowMinColor;
146        belowMinColor = aboveMaxColor;
147        aboveMaxColor = tmp;
148        return this;
149    }
150    
151    public void drawColorBar(Graphics2D g, int x, int y, int w, int h, double valueScale) {
152        int n=colors.length;
153        
154        for (int i=0; i<n; i++) {
155            g.setColor(colors[i]);
156            if (w<h) {
157                g.fillRect(x, y+i*h/n, w, h/n+1);
158            } else {
159                g.fillRect(x+i*w/n, y, w/n+1, h);
160            }
161        }
162        
163        int fw, fh;
164        FontMetrics fm = g.getFontMetrics(); 
165        fh = fm.getHeight()/2;
166        fw = fm.stringWidth(String.valueOf(Math.max((int)Math.abs(max*valueScale), (int)Math.abs(min*valueScale)))) + fm.stringWidth("0.123");
167        g.setColor(noDataColor);
168        if (title != null) {
169            g.drawString(title, x-fw-3, y-fh*3/2);
170        }
171        for (int i=0; i<=intervalCount; i++) {
172            g.setColor(colors[(int)(1.0*i*n/intervalCount-1e-10)]);
173            final double val =  min+i*(max-min)/intervalCount;
174            final String txt = String.format("%.3f", val*valueScale);
175            if (w<h) {
176                g.drawString(txt, x-fw-3, y+i*h/intervalCount+fh/2);
177            } else {
178                g.drawString(txt, x+i*w/intervalCount-fw/2, y+fh-3);
179            }
180        }
181    }
182}