QCustomPlot之K线图（十七）

K线图需要引入的类：QCPFinancial，首先来看下K线图的示意图：

其中阳线在中国一般使用红色表示，阴线使用绿色表示

K线图的数据结构

QCPFinancialData是QCPFinancial所使用的数据结构，包含五个数据类型，如下所示：

数据	含义
key	key轴坐标
open	开盘
close	关盘
low	最低
high	最高

K线图的风格

函数	含义
setChartStyle	csOhlc（美国线） csCandlestick（蜡烛图）
setWidth	wtAbsolute（像素） wtAxisRectRatio（轴矩形比例） wtPlotCoords（坐标轴，默认）
setTwoColored	是否显示两种颜色，即阳线和阴线可以有各自的颜色
setBrushPositive	阳线画刷
setBrushNegative	阴线画刷
setPenPositive	阳线画笔
setPenNegative	阴线画笔

timeSeriesToOhlc函数

如果数据仅有一系列值（例如价格与时间）可用，则可以使用静态函数timeSeriesToOhlc生成合并的OHLC数据，然后将其传递给setData函数

参数	含义
time	时间
value	值
timeBinSize	时间间隔大小，一般是一天（3600*24）
timeBinOffset	时间起始，一般传入time[0]

完整示例

来源：echarts

class MyAxisTickerText : public QCPAxisTickerText
{
protected:
    virtual QVector createTickVector(double tickStep, const QCPRange &range) Q_DECL_OVERRIDE
    {
        Q_UNUSED(tickStep)
        QVector result;
        if (mTicks.isEmpty())
            return result;

        auto start = mTicks.lowerBound(range.lower);
        auto end = mTicks.upperBound(range.upper);
        if (start != mTicks.constBegin()) --start;
        if (end != mTicks.constEnd()) ++end;

        int count = cleanMantissa(std::distance(start, end) / double(mTickCount + 1e-10));

        auto it = start;
        while (it != end) {
            result.append(it.key());
            int step = count;
            if (step == 0) ++it;
            while (--step >= 0 && it != end)
                ++it;
        }

        return result;
    }
};

void MainWindow::setupShangHaiIndexDemo(QCustomPlot *customPlot)
{
    const QColor BrushPositive("#ec0000");
    const QColor PenPositive("#8a0000");
    const QColor BrushNegative("#00da3c");
    const QColor PenNegative("#008f28");

    const QVector rawTimes = {
        "2013/1/24", "2013/1/25", "2013/1/28", "2013/1/29", "2013/1/30", "2013/1/31", "2013/2/1", "2013/2/4", "2013/2/5",  "2013/2/6", "2013/2/7",
        "2013/2/8",  "2013/2/18", "2013/2/19", "2013/2/20", "2013/2/21", "2013/2/22", "2013/2/25", "2013/2/26", "2013/2/27", "2013/2/28", "2013/3/1",
        "2013/3/4",  "2013/3/5",  "2013/3/6",  "2013/3/7", "2013/3/8",  "2013/3/11", "2013/3/12", "2013/3/13", "2013/3/14", "2013/3/15", "2013/3/18",
        "2013/3/19", "2013/3/20", "2013/3/21", "2013/3/22", "2013/3/25", "2013/3/26", "2013/3/27", "2013/3/28", "2013/3/29", "2013/4/1", "2013/4/2",
        "2013/4/3",  "2013/4/8",  "2013/4/9",  "2013/4/10", "2013/4/11", "2013/4/12", "2013/4/15", "2013/4/16", "2013/4/17", "2013/4/18", "2013/4/19",
        "2013/4/22", "2013/4/23", "2013/4/24", "2013/4/25", "2013/4/26", "2013/5/2",  "2013/5/3",  "2013/5/6",  "2013/5/7",  "2013/5/8",  "2013/5/9",
        "2013/5/10", "2013/5/13", "2013/5/14", "2013/5/15", "2013/5/16", "2013/5/17", "2013/5/20", "2013/5/21", "2013/5/22", "2013/5/23", "2013/5/24",
        "2013/5/27", "2013/5/28", "2013/5/29", "2013/5/30", "2013/5/31", "2013/6/3",  "2013/6/4",  "2013/6/5",  "2013/6/6",  "2013/6/7",  "2013/6/13",
    };
    // 数据意义：开盘(open)，收盘(close)，最低(lowest)，最高(highest)
    const QVector> rawDatas = {
        { 2320.26,2320.26,2287.3,2362.94}, { 2300,2291.3,2288.26,2308.38}, { 2295.35,2346.5,2295.35,2346.92}, { 2347.22,2358.98,2337.35,2363.8},
        { 2360.75,2382.48,2347.89,2383.76}, { 2383.43,2385.42,2371.23,2391.82}, {2377.41,2419.02,2369.57,2421.15}, {2425.92,2428.15,2417.58,2440.38},
        {2411,2433.13,2403.3,2437.42}, {2432.68,2434.48,2427.7,2441.73}, {2430.69,2418.53,2394.22,2433.89}, {2416.62,2432.4,2414.4,2443.03},
        { 2441.91,2421.56,2415.43,2444.8}, { 2420.26,2382.91,2373.53,2427.07}, { 2383.49,2397.18,2370.61,2397.94}, { 2378.82,2325.95,2309.17,2378.82},
        { 2322.94,2314.16,2308.76,2330.88}, { 2320.62,2325.82,2315.01,2338.78}, { 2313.74,2293.34,2289.89,2340.71}, { 2297.77,2313.22,2292.03,2324.63},
        { 2322.32,2365.59,2308.92,2366.16}, {2364.54,2359.51,2330.86,2369.65}, {2332.08,2273.4,2259.25,2333.54}, {2274.81,2326.31,2270.1,2328.14},
        {2333.61,2347.18,2321.6,2351.44}, {2340.44,2324.29,2304.27,2352.02}, {2326.42,2318.61,2314.59,2333.67}, { 2314.68,2310.59,2296.58,2320.96},
        { 2309.16,2286.6,2264.83,2333.29}, { 2282.17,2263.97,2253.25,2286.33}, { 2255.77,2270.28,2253.31,2276.22}, { 2269.31,2278.4,2250,2312.08},
        { 2267.29,2240.02,2239.21,2276.05}, { 2244.26,2257.43,2232.02,2261.31}, { 2257.74,2317.37,2257.42,2317.86}, { 2318.21,2324.24,2311.6,2330.81},
        { 2321.4,2328.28,2314.97,2332}, { 2334.74,2326.72,2319.91,2344.89}, { 2318.58,2297.67,2281.12,2319.99}, { 2299.38,2301.26,2289,2323.48},
        { 2273.55,2236.3,2232.91,2273.55}, { 2238.49,2236.62,2228.81,2246.87}, {2229.46,2234.4,2227.31,2243.95}, {2234.9,2227.74,2220.44,2253.42},
        {2232.69,2225.29,2217.25,2241.34}, {2196.24,2211.59,2180.67,2212.59}, {2215.47,2225.77,2215.47,2234.73}, { 2224.93,2226.13,2212.56,2233.04},
        { 2236.98,2219.55,2217.26,2242.48}, { 2218.09,2206.78,2204.44,2226.26}, { 2199.91,2181.94,2177.39,2204.99}, { 2169.63,2194.85,2165.78,2196.43},
        { 2195.03,2193.8,2178.47,2197.51}, { 2181.82,2197.6,2175.44,2206.03}, { 2201.12,2244.64,2200.58,2250.11}, { 2236.4,2242.17,2232.26,2245.12},
        { 2242.62,2184.54,2182.81,2242.62}, { 2187.35,2218.32,2184.11,2226.12}, { 2213.19,2199.31,2191.85,2224.63}, { 2203.89,2177.91,2173.86,2210.58},
        {2170.78,2174.12,2161.14,2179.65}, {2179.05,2205.5,2179.05,2222.81}, {2212.5,2231.17,2212.5,2236.07}, {2227.86,2235.57,2219.44,2240.26},
        {2242.39,2246.3,2235.42,2255.21}, {2246.96,2232.97,2221.38,2247.86}, { 2228.82,2246.83,2225.81,2247.67},  { 2247.68,2241.92,2231.36,2250.85},
        { 2238.9,2217.01,2205.87,2239.93}, { 2217.09,2224.8,2213.58,2225.19}, { 2221.34,2251.81,2210.77,2252.87}, { 2249.81,2282.87,2248.41,2288.09},
        { 2286.33,2299.99,2281.9,2309.39},  { 2297.11,2305.11,2290.12,2305.3},  { 2303.75,2302.4,2292.43,2314.18}, { 2293.81,2275.67,2274.1,2304.95},
        { 2281.45,2288.53,2270.25,2292.59}, { 2286.66,2293.08,2283.94,2301.7}, { 2293.4,2321.32,2281.47,2322.1}, { 2323.54,2324.02,2321.17,2334.33},
        { 2316.25,2317.75,2310.49,2325.72}, { 2320.74,2300.59,2299.37,2325.53}, {2300.21,2299.25,2294.11,2313.43}, {2297.1,2272.42,2264.76,2297.1},
        {2270.71,2270.93,2260.87,2276.86}, {2264.43,2242.11,2240.07,2266.69}, {2242.26,2210.9,2205.07,2250.63}, { 2190.1,2148.35,2126.22,2190.1}
    };

    QSharedPointer textTicker(new MyAxisTickerText);     // 文字轴
    textTicker->setTickCount(10);
    QCPDataContainer datas;
    QVector timeDatas, MA5Datas, MA10Datas, MA20Datas, MA30Datas;

    MA5Datas = calculateMA(rawDatas, 5);
    MA10Datas = calculateMA(rawDatas, 10);
    MA20Datas = calculateMA(rawDatas, 20);
    MA30Datas = calculateMA(rawDatas, 30);

    for (int i = 0; i < rawTimes.size(); ++i) {
        timeDatas.append(i);

        QCPFinancialData data;
        data.key = i;
        data.open = rawDatas.at(i).at(0);
        data.close = rawDatas.at(i).at(1);
        data.low = rawDatas.at(i).at(2);
        data.high = rawDatas.at(i).at(3);
        datas.add(data);

        textTicker->addTick(i, rawTimes.at(i));
    }
    

    QCPFinancial *financial = new QCPFinancial(customPlot->xAxis, customPlot->yAxis);
    financial->setName("日K");
    financial->setBrushPositive(BrushPositive);
    financial->setPenPositive(PenPositive);
    financial->setBrushNegative(BrushNegative);
    financial->setPenNegative(PenNegative);
    financial->data()->set(datas);

    const QVector ColorOptions = {
        "#c23531", "#2f4554", "#61a0a8", "#d48265"
    };

    QCPGraph *graph = customPlot->addGraph();
    graph->setName("MA5");
    graph->setData(timeDatas, MA5Datas);
    graph->setPen(ColorOptions.at(0));
    graph->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(ColorOptions.at(0), 2), QBrush(Qt::white), 8));
    graph->setSmooth(true);

    graph = customPlot->addGraph();
    graph->setName("MA10");
    graph->setData(timeDatas, MA10Datas);
    graph->setPen(ColorOptions.at(1));
    graph->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(ColorOptions.at(1), 2), QBrush(Qt::white), 8));
    graph->setSmooth(true);

    graph = customPlot->addGraph();
    graph->setName("MA20");
    graph->setData(timeDatas, MA20Datas);
    graph->setPen(ColorOptions.at(2));
    graph->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(ColorOptions.at(2), 2), QBrush(Qt::white), 8));
    graph->setSmooth(true);

    graph = customPlot->addGraph();
    graph->setName("MA30");
    graph->setData(timeDatas, MA30Datas);
    graph->setPen(ColorOptions.at(3));
    graph->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(ColorOptions.at(3), 2), QBrush(Qt::white), 8));
    graph->setSmooth(true);

    customPlot->xAxis->setTicker(textTicker);
    customPlot->rescaleAxes();
    customPlot->xAxis->scaleRange(1.05, customPlot->xAxis->range().center());
    customPlot->yAxis->scaleRange(1.05, customPlot->yAxis->range().center());
    customPlot->legend->setVisible(true);
}

QVector MainWindow::calculateMA(const QVector > &v, int dayCount)
{
    auto func = [](double result, const QVector &v2){
      return result + v2[1];
    };

    QVector result;
    for (int i = 0; i < v.size(); ++i) {
        if (i < dayCount) {
            result.append(qQNaN());
        } else {
            double sum = std::accumulate(v.begin() + i - dayCount + 1, v.begin() + i + 1, 0.0, func);
            result.append(sum / dayCount);
        }
    }
    return result;
}

最后

1. 不使用 QCPAxisTickerDateTime 作为轴标签，是因为数据的日期不是连续的，使用QCPAxisTickerDateTime会导致不连续的部分有间隔，如果需要使用QCPAxisTickerDateTime的话需要设置setTickOrigin为时间的第一个数据，不然的话会发生K线图与坐标轴对应不上的情况，同时还要设置K线图的宽度setWidth，例如一天的宽度financial->setWidth(3600 * 24 * 0.8)，乘以0.8是为了稍微缩小一点
2. 继承QCPAxisTickerText的原因是因为QCPAxisTickerText在数据比较多的时候轴标签会挤在一起，密密麻麻的不好看