前言

媳妇公司有个需求，就是画立体柱状图的图表，本想使用hightcharts 画，效果和设计图出入太大，立体柱状图还需要渐变色，以及平面状态下展示立体效果，因此找到我帮忙画一个。

一、先上效果图

效果图

二、代码

dom结构

<div>
  <div id="mainbar" class="mainbar"></div>
</div>

css样式

.mainbar {
    height: 400px;
    width: 800px;
}

// 柱状图宽度
let barWidth = 30
// 图表容器高度（为计算贴花高度）
let wrapHeight = 400
// 上边距
let gridTop = 50
// 下边距
let gridBottom = 50

// 计算容器内图表渲染区高度（为计算贴花高度）
let innerHeight = wrapHeight - gridTop - gridBottom

let data1 = [120, 200, 150, 80, 70, 110, 130]
let max = Math.max(...data1)

let rat = innerHeight / max

// 通过容器高度，边距 计算贴花位置与大小
function calcDecal(v) {
    return {
        // 渐变图，随便用ps画一个导出，转成base64
        symbol: 'image://data:image/png;base64,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',
        dashArrayX: [barWidth, 0],
        dashArrayY: [gridTop + rat * (max - v), 0, rat * v],
        symbolKeepAspect: false,
        maxTileWidth: 10000,
        maxTileHeight: 10000,
    }
}

// 根据颜色数组设置渐变色 例如 ['#057179','#00c8af','#00ffe1','#01f5da']
function calcColor(colors = []) {
    return {
        type: 'linear',
        x: 0, x2: 1, y: 0, y2: 0,
        colorStops: [
            {
                offset: 0,
                color: colors[0] || '#055d84'
            },
            {
                offset: 0.5,
                color: colors[1] || '#0092c1'
            },
            {
                offset: 0.5,
                color: colors[2] || '#00c6fe'
            },
            {
                offset: 1,
                color: colors[3] || '#01baf5'
            }
        ]
    }
}

function renderBar() {
    let chartDom = document.getElementById('mainbar');
    let myChart = echarts.init(chartDom);
    let option;
    option = {
        backgroundColor: '#0b2953',
        xAxis: {
            type: 'category',
            data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
        },
        yAxis: {
            type: 'value'
        },
        grid: {
            top: gridTop,
            bottom: gridBottom,
        },
        legend: {
            top: 0,
            right: 10,
            textStyle: {
                color: '#ffffff'
            }
        },
        series: [
            {
                name: '待处理',
                type: 'bar',
                barWidth: barWidth,
                data: data1.map(v => {
                    return {
                        value: v,
                        itemStyle: {
                            decal: calcDecal(v)
                        }
                    }
                }),
                itemStyle: {
                    color: calcColor(),
                },
            },
            {
                name: '待处理',
                z: 3,
                type: 'pictorialBar',
                symbolPosition: 'end',
                data: data1,
                symbol: 'diamond',
                symbolOffset: ['0', '-50%'],
                symbolSize: [barWidth, barWidth * 0.4],
                itemStyle: {
                    normal: {
                        color: '#00ddfe',
                    },
                },
            }



        ]
    };

    option && myChart.setOption(option);
    setTimeout(()=>{
        myChart.resize()
    }, 10)
}
renderBar()