Question

I wish to have a large array of QColors that many classes will share and index from.

In the past, I’ve always had the list like such:

QColor colours[10] = {QColor("cyan"), QColor("magenta"), QColor("red"),
                      QColor("darkRed"), QColor("darkCyan"), QColor("darkMagenta"),
                      QColor("green"), QColor("darkGreen"), QColor("yellow"),
                      QColor("blue")};

However, now I want many more than 10. How can I create a large list of different QColors?

Answer 1

if you want your list to be dynamic, I would use some sort of QVector instead, wrapped in a Color Manager for example :

    class ColorManager
    {
        public:
            ColorManager(size_t iDefaultSize)
            {
                m_colorList.reserve(iDefaultSize);
            }

            void addColor(const QColor& c)
            {
                m_colorList.push_back(c);
            }

            QColor& operator[](int iIndex)
            {
                return m_colorList.at(iIndex);
            }

        private:
            QVector m_colorList;
    };

If your colors have to be unique, consider using a QSet, but you loose the [] operator as QSet are ordered structure, and you will have to implement a find in ColorManager, using QSet::find(). It will also be slower.
If it has to be thread safe, you can eventually protect it with QMutex.

Also, I don’t know why you need this, but you should have a look at :

QColorGroup and / or QPalette