sample not spread over the chart

[hodbauer]

Hello, I'm using next versions of chart.js:

chart.js: 2.8.0
chartjs-plugin-zoom: 0.7.0
chartjs-plugin-downsample: 1.1.0

I have the next configuration for my graph:

const config = {
  type: 'line',
  options: {
    downsample: {
      enabled: true
    },
    plugins: {
      zoom: {
        zoom: {
          enabled: true,
          mode: 'x'
        }
      }
    }
  }
}

I create a graph and only after a few milliseconds the data arrived from a server. I have thousands of points (almost 20K points).

After I update the graph with the data i call chart.update() to render the data.

As I expected, there is only 1000 points that displayed on the canvas, but the points appears only in the beginning of the graph (unfortunately I cannot add snapshot of the situation), it's mean that the x axes has a relevant range for all my points but the data not spread from begin to end. As a workaround to check what went wrong I call manually to chart.downsample(1000) and then chart.update() and it fix the problem, but I dont think that this should be the solution.

can I get any hint what i do wrong?

[kmlbgn]

Running into the same problem... ended up doing the same, stealing the downsample() function, and doing it manually. Something is not properly behaving in the script.

[AlbinoDrought]

I realize this issue was opened quite some time ago, but in case it is still any help, does the newly-added data render as expected if the configuration has preferOriginalData: true?

const config = {
  type: 'line',
  options: {
    downsample: {
      enabled: true,
      preferOriginalData: true,
    },
    plugins: {
      zoom: {
        zoom: {
          enabled: true,
          mode: 'x'
        }
      }
    }
  }
}

I've added a new sample here for https://github.com/AlbinoDrought/chartjs-plugin-downsample/issues/10#issuecomment-695146250 that adds data dynamically and it requires preferOriginalData: true to work.