Cannot stack bars on time x-axis

One-line summary [问题简述]

Stacked bar charts collapsed since 4.0.3. See screenshot.

Version & Environment [版本及环境]

• ECharts version [ECharts 版本]: 4.0.4
• Browser version [浏览器类型和版本]: Chrome 64
• OS Version [操作系统类型和版本]: macOS High Sierra

Expected behaviour [期望结果]

Bars able to stack on top of each other without overflowing issues.

ECharts option [ECharts配置项]

option = { 
  grid: {
    right: '8%',
    left: '8%'
  },
  xAxis: {
      type: 'time',
      minInterval: 1000 * 3600 * 24
  },
  yAxis: {
    type: 'value',
    min: 0,
    max: 100,
    name: '%'
  },
  series: [
  {
    type: 'bar',
    stack: 'adherence',
   data: [{
       value: ['2018-02-21', 6, 2, 33, 67]
     }],
    encode: { x: 0, y: 3 },
    barMaxWidth: 25,
    barCategoryGap: '50%',
    cursor: 'auto',
    itemStyle: {
      normal: {
        color: 'red',
        opacity: 0.5
      }
    }
  },
  {
    type: 'bar',
    stack: 'adherence',
    data: [{
       value: ['2018-02-21', 6, 2, 33, 67]
     }],
    encode: { x: 0, y: 4 },
    barMaxWidth: 25,
    barCategoryGap: '50%',
    cursor: 'auto',
    itemStyle: {
      normal: {
        color: 'green',
        opacity: 0.5
      }
    }
  }],
  dataZoom: {
    type: 'slider',
    showDataShadow: false
  }
}

Other comments [其他信息]

Switching x-axis type to 'category' solved the problem. But unsure why issue only arose after version upgrade from 4.0.2 to 4.0.4.

Reopened because I need to use time for x-axis 😞

[saramorillon]

I have the same problem, stacked bar chart with time x-axis worked in 4.0.2 but not until 4.0.3.

[100pah]

Currently, stack is only supported on 'category' axis.

In fact, we've been considering whether support stack on 'time' or event 'value' axis, since it is a bit complicated than supporting it on 'category' axis.

@ClaraMedopad Could I have the detailed reason that why the 'time' axis is necessary in your case?

In my case I use it to visualise medication adherence, i.e. how many tablets a patient has taken out of the total per day. I want to have an overview of the continuous data, i.e. if the medication is stopped or not required for the day, a gap will be shown in the bar chart.

Example in the above screenshot, 2017-08-05 and 2017-08-07 does not show because no medication is prescribed, but it will be helpful to visualise that to the doctor.

A bar chart is used in this case to visualise the percentage completion of the daily dosage. I cannot think of alternative ways to display it other than stacked bar on time axis so any advice is welcomed.

[BenoitHanotte]

Same issue here, I use echarts to visualize memory consumption over time and I stack the memory usages to display the repartition of the overall memory usage.
eg: heap memory + off-heap memory = total memory consumed, thus I want to stack series as in the following plot:

[Xalio08]

Same issue, I need to stack registrations of different types at different dates, and categories doesn't work since some days are empty and should still appear.

[tmtron]

our use-case is almost like the Confidence Band example, but:

• but for the line-series, we need the time axis
• for the confidence band we could use a category axis

any ideas for a workaround? e.g.

1. maybe we can have 2 x-axis: a time-axis for the line-series and a category axis for the (confidence band stack)?
   But those axis would need to be "sychronized": e.g. when we zoom in, both must zoom together, etc.
2. or is it worth to try to keep only one time-axis and use a custom series to draw the area?
   If so, can someone link to an example, how to use custom-series with a time x-axis?
   The answer is NO. Custom series are just too slow (much slower than native series). Drawing the graphics basically works, but when we have like 10 charts with 5 series and 1k samples, the app is basically unusable.
3. something completely different, that I didn't think of..

[tmtron]

In fact, we've been considering whether support stack on 'time' or event 'value' axis, since it is a bit complicated than supporting it on 'category' axis.

@100pah: will it be simpler to support only a special case and not the general case to stack 2 different series (which may have data-samples at different time-stamps)?

e.g. when you have measurement data, you often need to display the min and max values of a series (instead of just e.g. the average) to avoid aliasing: e.g. in the screenshot below we have one such series (1) is the maximum and (2) is the minimum: so each of the samples have a time-stamp and they always have min and max: