// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.tools;
import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
/**
* Utility class that helps to work with color scale for coloring GPX tracks etc.
* @since 7319
*/
public final class ColorScale {
private double min, max;
private Color noDataColor;
private Color belowMinColor;
private Color aboveMaxColor;
private Color[] colors;
private String title = "";
private int intervalCount = 5;
private ColorScale() {
}
public static ColorScale createHSBScale(int count) {
ColorScale sc = new ColorScale();
sc.colors = new Color[count];
for (int i = 0; i < count; i++) {
sc.colors[i] = Color.getHSBColor(i / 300.0f, 1, 1);
}
sc.setRange(0, 255);
sc.addBounds();
return sc;
}
public static ColorScale createCyclicScale(int count) {
ColorScale sc = new ColorScale();
// CHECKSTYLE.OFF: SingleSpaceSeparator
// red yellow green blue red
int[] h = new int[] {0, 59, 127, 244, 360};
int[] s = new int[] {100, 84, 99, 100};
int[] b = new int[] {90, 93, 74, 83};
// CHECKSTYLE.ON: SingleSpaceSeparator
sc.colors = new Color[count];
for (int i = 0; i < sc.colors.length; i++) {
float angle = i / 256f * 4;
int quadrant = (int) angle;
angle -= quadrant;
quadrant = Utils.mod(quadrant+1, 4);
float vh = h[quadrant] * w(angle) + h[quadrant+1] * (1 - w(angle));
float vs = s[quadrant] * w(angle) + s[Utils.mod(quadrant+1, 4)] * (1 - w(angle));
float vb = b[quadrant] * w(angle) + b[Utils.mod(quadrant+1, 4)] * (1 - w(angle));
sc.colors[i] = Color.getHSBColor(vh/360f, vs/100f, vb/100f);
}
sc.setRange(0, 2*Math.PI);
sc.addBounds();
return sc;
}
/**
* transition function:
* w(0)=1, w(1)=0, 0<=w(x)<=1
* @param x number: 0<=x<=1
* @return the weighted value
*/
private static float w(float x) {
if (x < 0.5)
return 1 - 2*x*x;
else
return 2*(1-x)*(1-x);
}
public void setRange(double min, double max) {
this.min = min;
this.max = max;
}
/**
* Add standard colors for values below min or above max value
*/
public void addBounds() {
aboveMaxColor = colors[colors.length-1];
belowMinColor = colors[0];
}
public Color getColor(double value) {
if (value < min) return belowMinColor;
if (value > max) return aboveMaxColor;
if (Double.isNaN(value)) return noDataColor;
final int n = colors.length;
int idx = (int) ((value-min)*colors.length / (max-min));
if (idx < colors.length) {
return colors[idx];
} else {
return colors[n-1]; // this happens when value==max
}
}
public Color getColor(Number value) {
return (value == null) ? noDataColor : getColor(value.doubleValue());
}
public Color getNoDataColor() {
return noDataColor;
}
public void setNoDataColor(Color noDataColor) {
this.noDataColor = noDataColor;
}
public ColorScale makeTransparent(int alpha) {
for (int i = 0; i < colors.length; i++) {
colors[i] = new Color((colors[i].getRGB() & 0xFFFFFF) | ((alpha & 0xFF) << 24), true);
}
return this;
}
public ColorScale addTitle(String title) {
this.title = title;
return this;
}
public ColorScale setIntervalCount(int intervalCount) {
this.intervalCount = intervalCount;
return this;
}
public ColorScale makeReversed() {
int n = colors.length;
Color tmp;
for (int i = 0; i < n/2; i++) {
tmp = colors[i];
colors[i] = colors[n-1-i];
colors[n-1-i] = tmp;
}
tmp = belowMinColor;
belowMinColor = aboveMaxColor;
aboveMaxColor = tmp;
return this;
}
public void drawColorBar(Graphics2D g, int x, int y, int w, int h, double valueScale) {
int n = colors.length;
for (int i = 0; i < n; i++) {
g.setColor(colors[i]);
if (w < h) {
g.fillRect(x, y+i*h/n, w, h/n+1);
} else {
g.fillRect(x+i*w/n, y, w/n+1, h);
}
}
int fw, fh;
FontMetrics fm = g.getFontMetrics();
fh = fm.getHeight()/2;
fw = fm.stringWidth(String.valueOf(Math.max((int) Math.abs(max*valueScale),
(int) Math.abs(min*valueScale)))) + fm.stringWidth("0.123");
g.setColor(noDataColor);
if (title != null) {
g.drawString(title, x-fw-3, y-fh*3/2);
}
for (int i = 0; i <= intervalCount; i++) {
g.setColor(colors[(int) (1.0*i*n/intervalCount-1e-10)]);
final double val = min+i*(max-min)/intervalCount;
final String txt = String.format("%.3f", val*valueScale);
if (w < h) {
g.drawString(txt, x-fw-3, y+i*h/intervalCount+fh/2);
} else {
g.drawString(txt, x+i*w/intervalCount-fw/2, y+fh-3);
}
}
}
}