Hey there! I get your frustration—Chart.js v4 made some breaking changes to how these lines are configured, ditching the old zeroLine options for more flexible grid and border settings. Here's how you can make those darker lines match your grid color perfectly:

Key Adjustments Needed #

There are two main culprits behind the darker lines:

1. The axis border (like the -1.0 line if that’s your y-scale minimum) uses a default darker color by default.
2. The old zeroLine option was removed in v4, so we need to ensure zero blends into the regular grid lines.

Modified Configuration Code #

Here’s your updated config with the fixes applied:

const ctx = document.getElementById('chart') as HTMLCanvasElement;
chart.value = new Chart(ctx, {
  type: 'bar',
  data: { datasets: [] },
  options: {
    onClick: (evt) => handleOnClick(evt),
    interaction: { mode: 'nearest' },
    plugins: {
      legend: {
        labels: {
          generateLabels(chart) {
            // your existing code here
          }
        }
      },
      title: { display: true, text: 'My Super cool Chart' }
    },
    scales: {
      x: {
        grid: {
          color: myBackgroundColor, // Applies to all grid lines including zero
          drawBorder: false // Optional: Disable outer border to use grid-style lines
        },
        beginAtZero: false,
        ticks: {
          callback: (value) => doSomethingOnCallaback(value)
        },
        type: 'linear',
        border: { color: myBackgroundColor } // Match border to grid color if keeping drawBorder true
      },
      y: {
        grid: {
          color: myBackgroundColor, // Uniform color for all grid lines (including zero)
          drawBorder: false // Optional: Turn off outer border to align with grid
        },
        max: myStart,
        min: myEnd,
        beginAtZero: false,
        ticks: {
          callback: (value) => `Tick ${value}`,
          stepSize: 15.0
        },
        border: { color: myBackgroundColor } // Match y-axis border to grid color
      }
    }
  }
});

Breakdown of Changes #

• Axis Border Matching: The scales[axis].border.color property sets the outer axis lines (like your -1.0 line) to the same color as your grid. If you’d rather remove the border entirely and have min/max lines act as grid lines, set grid.drawBorder: false.
• Zero Line Integration: Since zeroLine is gone, setting grid.color directly to your myBackgroundColor ensures the zero line uses the same style as all other grid lines. No special callback is needed unless you want conditional styling.

Quick Tip #

If myBackgroundColor is a static color string (not a dynamic function), you can just pass it directly to grid.color instead of using a callback—Chart.js will apply it to every grid line automatically.

That should make all those darker lines blend seamlessly with your grid! Let me know if you hit any snags.

内容的提问来源于stack exchange，提问作者ekjcfn3902039