BarSeries class

Bars anchored at each data point's x value.

Data points are usually BarPoints (floating fromY, per-point style); plain ChartPoints also work and paint as zero-based bars in the series style. Gap points paint nothing but keep their slot addressable.

Alignment recipes

There is no alignment enum: bars are anchored at data values, so alignment is a property of the x values plus the axis range. Each of the usual alignments is a range recipe. For N bars at x = 0..N-1:

• spaceAround / spaceEvenly — give every bar an equal slot with a half-slot margin at each plot edge: NumericAxis(range: AxisRange.fixed(-0.5, N - 0.5)). Nothing clips; this is the usual look for a categorical month/day strip.
• spaceBetween — pin the first and last bar centers to the plot edges: NumericAxis(range: AxisRange.fixed(0, N - 1)). The outer bars straddle the edges, so their outer halves clip.
• center — shrink the fixed range's padding around the same x values, e.g. AxisRange.fixed(-2, N + 1) leaves 1.5 empty slots per side; grow the numbers to push the group tighter into the middle.

Bar thickness is chosen independently of the recipe: BarWidth.pixels for a fixed thickness, or BarWidth.xSpan to fill a fraction of each slot (e.g. BarWidth.xSpan(0.6) on unit-spaced data) so bars scale with the plot instead of the range. On a scrollable axis (AxisResolution.perUnit) there is no alignment to pick — the range follows the scroll position and BarWidth.xSpan keeps bar-to-gap proportion constant at any resolution.

For side-by-side grouped bars, combine any recipe with xOffsetPx and barClusterOffset.