sparklinekit/bar

SVG and PNG bar sparklines.

import sparklinekit/bar
import sparklinekit/theme

pub fn revenue() -> String {
  bar.new([3.0, 7.0, 2.0, 9.0, 5.0])
  |> bar.with_theme(theme.sunset())
  |> bar.with_corner_radius(2.0)
  |> bar.to_svg
}

Positive and negative values share a zero baseline: positives rise above it, negatives fall below. with_negative_color paints the falling bars in a contrasting colour so win/loss charts read at a glance.

Types

Builder

opaque </>

Opaque builder for a bar sparkline.

pub opaque type Builder

Values

new

</>

pub fn new(values: List(Float)) -> Builder

Start a new bar sparkline builder.

Defaults: 200x40 viewBox, currentColor fill, 1.0px gap between bars, no rounded corners, no background.

new_ints

</>

pub fn new_ints(values: List(Int)) -> Builder

Start a builder from a list of Int values.

to_png

</>

pub fn to_png(builder: Builder) -> BitArray

Render the builder to PNG bytes (8-bit RGBA truecolor). The viewBox dimensions double as the pixel size.

The PNG IDAT payload is written using DEFLATE’s uncompressed “store” blocks (no Huffman coding) so the encoder stays pure Gleam with zero FFI. As a result the output is roughly width * height * 4 bytes regardless of how uniform the image is — for visual size context, prefer SVG.

to_svg

</>

pub fn to_svg(builder: Builder) -> String

Render the builder to a self-contained <svg> element string.

with_background_color

</>

pub fn with_background_color(
  builder: Builder,
  color: String,
) -> Builder

Set the background rectangle colour. "none" disables the background.

with_bar_gap

</>

pub fn with_bar_gap(builder: Builder, gap: Float) -> Builder

Set the gap between adjacent bars in user units. The per-bar width is derived from the total width, bar count, and this gap. Negative values are clamped to 0.0.

with_color

</>

pub fn with_color(builder: Builder, color: String) -> Builder

Set the positive-bar fill colour (any CSS colour string).

with_corner_radius

</>

pub fn with_corner_radius(
  builder: Builder,
  radius: Float,
) -> Builder

Set the corner radius in user units. The renderer clamps the radius to half the smaller side of each individual bar so the shape stays a rectangle / capsule rather than turning into a circle.

with_int_values

</>

pub fn with_int_values(
  builder: Builder,
  values: List(Int),
) -> Builder

Replace the data series with a list of Ints.

with_negative_color

</>

pub fn with_negative_color(
  builder: Builder,
  color: String,
) -> Builder

Use a separate colour for bars below the zero baseline.

with_size

</>

pub fn with_size(
  builder: Builder,
  width: Int,
  height: Int,
) -> Builder

Set the viewBox / pixel dimensions. Non-positive values are normalised to 1.

with_theme

</>

pub fn with_theme(
  builder: Builder,
  theme: theme.Theme,
) -> Builder

Apply every colour slot from theme. The theme’s negative colour is used for bars below the zero baseline; calling with_negative_color afterwards overrides just that slot.

with_values

</>

pub fn with_values(
  builder: Builder,
  values: List(Float),
) -> Builder

Replace the data series after construction.