-
- /**
- * Generates a colour that is interpolated between
- * <code>colour.darker()</code> and <code>colour.brighter()</code> in
- * proportion as <code>value</code> is between <code>min</code> and
- * <code>max</code>. Note that the 'neutral point' (unchanged colour) is
- * closer to 'brighter' than to 'darker'as this is a geometric range.
- *
- * @param value
- * @param min
- * @param max
- * @param colour
- * @return
- */
- public static Color getGraduatedColour(float value, float min, float max,
- Color colour)
- {
- /*
- * this computes the equivalent of
- * getGraduatedColour(value, min, colour.darker(), max, colour.brighter())
- * but avoiding object creation except for the return value
- */
- if (value < min)
- {
- value = min;
- }
- if (value > max)
- {
- value = max;
- }
-
- int r = colour.getRed();
- int g = colour.getGreen();
- int b = colour.getBlue();
-
- /*
- * rgb for colour.darker():
- */
- float minR = r * FACTOR;
- float minG = g * FACTOR;
- float minB = b * FACTOR;
-
- /*
- * rgb for colour.brighter():
- */
- float maxR = Math.min(255f, r / FACTOR);
- float maxG = Math.min(255f, g / FACTOR);
- float maxB = Math.min(255f, b / FACTOR);
-
- /*
- * interpolation
- */
- float p = (value - min) / (max - min);
- int newR = (int) (minR + p * (maxR - minR));
- int newG = (int) (minG + p * (maxG - minG));
- int newB = (int) (minB + p * (maxB - minB));
-
- return new Color(newR, newG, newB, colour.getAlpha());
- }