A 2D drawing surface for plotting shapes in arbitrary coordinate space.

Wraps Ratatui's Canvas widget. Define the coordinate window with :x_bounds and :y_bounds — both {min, max} tuples — and paint into it by listing shape structs in :shapes. Each shape carries its own color; the canvas only controls the marker resolution and the optional background wash.

Supported shapes live under ExRatatui.Widgets.Canvas.*:

• Line - %Line{x1, y1, x2, y2, color}
• Rectangle - %Rectangle{x, y, width, height, color} (bottom-left anchored, outline only)
• Circle - %Circle{x, y, radius, color} (center anchored, outline only)
• Points - %Points{coords: [{x, y}], color}
• Map - %Map{resolution, color} (world map; pair with {-180, 180} × {-90, 90} bounds)
• Label - %Label{x, y, text, color} (text annotation drawn on top of the canvas)

Markers

The :marker controls how canvas coordinates map to cell pixels:

• :braille (default) - 2×4 sub-cell pixels, best for lines/curves
• :dot - one glyph per cell
• :block - solid block, good for heatmaps
• :bar - half-height bar
• :half_block - 1×2 sub-cell pixels

Fields

• :x_bounds - {min, max} tuple bounding the X axis (required)
• :y_bounds - {min, max} tuple bounding the Y axis (required)
• :marker - one of :braille, :dot, :block, :bar, :half_block (default :braille)
• :background_color - ExRatatui.Style.color() washed behind shapes; nil falls back to the terminal default
• :shapes - list of shape structs (default [])
• :block - optional %ExRatatui.Widgets.Block{} container

Examples

iex> alias ExRatatui.Widgets.Canvas
iex> alias ExRatatui.Widgets.Canvas.Line
iex> %Canvas{
...>   x_bounds: {0.0, 10.0},
...>   y_bounds: {0.0, 10.0},
...>   shapes: [%Line{x1: 0.0, y1: 0.0, x2: 10.0, y2: 10.0, color: :red}]
...> }
%ExRatatui.Widgets.Canvas{
  x_bounds: {0.0, 10.0},
  y_bounds: {0.0, 10.0},
  marker: :braille,
  background_color: nil,
  shapes: [
    %ExRatatui.Widgets.Canvas.Line{x1: 0.0, y1: 0.0, x2: 10.0, y2: 10.0, color: :red}
  ],
  block: nil
}