Equidistant ticks on axis

[daniel-eh]

Question

Hello.

I'm looking to place ticks equidistant-ish from each other on the axis. So for a simple example, if I have 100 x values, I want to plot them all but I only want a tick on the x-axis at every 20 (20, 40, 60, 80). I don't necessarily know how many data points I'll get, so I'd like to be able to essentially just pass an argument for how many ticks go in the axis, evenly spread. There's a picture attached to sort of demonstrate this.

I suspect I'm supposed to achieve this via xStep but I've been struggling to get it to work/look the way I need it to.

Thanks for any help!

Vico version(s)

2.0.0-beta.3

UI framework(s)

Jetpack Compose

[Gowsky]

Hello, @daniel-eh. If the tick logic is entirely static like this, then you may get random values along the x-axis. Let's take 4 ticks. For 100 values, it works fine: 20, 40, 60, 80. However, if you had 93 values, you'd get 18.6, 32.7, 55.8, and 74.4. Is that desired?

[daniel-eh]

More or less. To give a little more clarity, an API gives me a dataset with a date that consists of dates and a number associated with each, so the x-axis is the dates and the y-axis is the number. The graph should just show ticks to broadly represent each month, kinda like the picture I attached above, but each point in the dataset still gets plotted. I don't know how many dates will be included since the dataset can vary in size/time covered.

For now what I've done is just hide the graph's x-axis and just draw a horizontal line on a canvas under the graph, and pass in how many months there are and draw equidistant ticks and labels. So it's not actually part of the graph, it's just a fake. This works for now, but I'm hoping to just use the graph to accomplish this rather than having to maintain a separate composable to fake the look.

[Gowsky]

Generally, you can achieve this via HorizontalAxis.ItemPlacer. We'd need some more information to describe the optimal solution in greater detail.

Could you tell us more about the x values? Are they Unix timestamps? Also, does the data always include full months, or could it be e.g. January 25 to April 17? If the latter is possible, then what, exactly, is the desired behavior in such a case?

[daniel-eh]

The timestamps will be a Kotlin LocalDate in the format YYYY-MM-DD - for the purposes of a label I would just be grabbing the month from the LocalDate and showing it's abbreviation as a tick on the x-axis ("Mar", "Apr", "May", etc). The user doesn't need to see the entire date, the ticks are just to show a generalized change over time. The days will be consecutive as well (2025-01-15, 2025-01-16, 2025-01-17)