Crate weirdnet_render 

weirdnet-render

Structured data drawn to PNG. Inputs are plain data, not any application’s types:

• Table: column names and rows of text cells, drawn as a grid with an 8×8 bitmap font (numbers right-aligned, long cells cut with ~, characters without a glyph shown as ?).
• Chart: x values and named series of numbers (gaps allowed), drawn as a line chart; legend names each series’ color.
• JSON describing either one (json_png, Drawing::from_json):
  • {"columns": ["a", "b"], "rows": [[1, "x"], [2, null]]}, a table;
  • [{"a": 1, "b": "x"}, {"a": 2}], a table whose columns are the keys, sorted;
  • [[1, "x"], [2, "y"]], a table with columns 1, 2, …;
  • {"x": [0, 1, 2], "series": [{"name": "a", "values": [1, null, 3]}], "width": 900, "height": 320}, a chart (x, width and height are optional).

Every entry point checks its input against Limits (columns, rows, cell length, series, points, image width, height and pixel count, JSON size) and returns an Error instead of drawing something unbounded. A chart with no finite value is Error::Empty.

use weirdnet_render::{Limits, Table, table_png, json_png};
let t = Table { columns: vec!["name".into(), "temp".into()], rows: vec![vec!["north".into(), "21.5".into()]] };
let png = table_png(&t, &Limits::default()).unwrap();
assert_eq!(&png[1..4], b"PNG");
let png = json_png(r#"{"series":[{"name":"t","values":[1,2,3]}]}"#, &Limits::default()).unwrap();
assert_eq!(&png[1..4], b"PNG");

The crate knows nothing about where the data comes from; an application translates its own result types into these (Muninn does that for code-space charts in reports).

BSD-3-Clause. The glyphs come from the font8x8 crate (MIT).

Structs

Chart

A line chart: x positions (a missing one is its index) and the series over them.

Limits

What a caller is willing to have drawn. Anything over a limit is an Error::TooLarge.

Series

One line of a chart; None (or a non-finite number) is a gap.

Table

A table: column names and rows of cell text (each row as long as columns).

Enums

Drawing

Something to draw, as read from JSON.

Error

Constants

CHART_HEIGHT

CHART_WIDTH

Default chart size when JSON does not give one.

Functions

chart_png

Draw the series over x as a width×height PNG. Error::Empty when no value (or no x) is there to draw.

json_png

Read JSON text (at most max_json_bytes) as a table or chart and draw it.

legend

The legend: series names with their colors’ names, in drawing order.

render

Draw a table or a chart.

table_png

Draw a table as PNG; its size follows from the text (checked against the limits first).

Type Aliases

Result