如何动态计算颜色列表？ [英] How to dynamically compute a list of colors?

问题描述

为了在GWT-Widget中表示不同颜色的对象列表，我们需要动态地获取与对象具有不同颜色的颜色列表。由于列表的大小可以不同，因此我们需要能够计算这种颜色列表。

In order to represent a List of Objects with different colors in a GWT-Widget, we need to get dynamically a List of colors with as much different colors as objects. Since the size of the List can vary, we need to be able to compute such a List of colors.

推荐答案

我的解决方案范围：

List<int> getUniqueColors(int amount) {
    final int lowerLimit = 0x10;
    final int upperLimit = 0xE0;    
    final int colorStep = (upperLimit-lowerLimit)/Math.pow(amount,1f/3);

    final List<int> colors = new ArrayList<int>(amount);

    for (int R = lowerLimit;R < upperLimit; R+=colorStep)
        for (int G = lowerLimit;G < upperLimit; G+=colorStep)
            for (int B = lowerLimit;B < upperLimit; B+=colorStep) {
                if (colors.size() >= amount) { //The calculated step is not very precise, so this safeguard is appropriate
                    return colors;
                } else {
                    int color = (R<<16)+(G<<8)+(B);
                    colors.add(color);
                }               
            }
    return colors;
}

这一个更加先进，因为它产生彼此不同的颜色尽可能多的东西（像@aiiobe做）。

This one is more advance as it generates the colors that differ from each other as much as possible (something like @aiiobe did).

一般来说，我们将范围分为红色绿色和蓝色的3个子范围，计算我们需要迭代多少步数（通过应用pow（range，1f / 3））并迭代它们。

Generally we split the range to 3 subranges of red green and blue, calculate how many steps do we need to iterate each of them (by applying a pow(range,1f/3)) and iterate them.

例如，给定数字3，它将生成 0x0000B1,0x00B100,0x00B1B1 。对于数字10，它将是： 0x000076,0x0000EC，0x007600,0x007676,0x0076EC，0x00EC00,0x00EC76,0x00ECEC，0x760000,0x760076

Given the number 3 for example, it will generate 0x0000B1, 0x00B100, 0x00B1B1. For number 10 it will be: 0x000076, 0x0000EC, 0x007600, 0x007676, 0x0076EC, 0x00EC00, 0x00EC76, 0x00ECEC, 0x760000, 0x760076

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