CanvasCraft (canvas_craft v0.2.0)

View Source

CanvasCraft - 2D graphics drawing library facade.

This module delegates drawing operations to the Skia backend by default. The canvas handle is represented as {backend_module, backend_ref}.

Examples:

  • In-memory WEBP export (no temp files): iex> {:ok, handle} = CanvasCraft.create_canvas(16, 16) iex> {:ok, bin} = CanvasCraft.export_webp(handle) iex> is_binary(bin) true

See guides/examples/ for runnable scripts demonstrating gradients, filters, images, and in-memory export.

Summary

Types

canvas_handle()

Backend-qualified canvas handle

Functions

capabilities(backend)

Return capabilities supported by the selected backend

clear(arg, rgba)

Clear the canvas to a given RGBA color (tuple {r,g,b,a}, 0..255). No-op for backends that don't support it yet.

create_canvas(width, height, opts \\ [])

Create a new canvas using the selected backend.

draw_text(arg1, x, y, text, arg2)

Draw UTF-8 text at x,y with RGBA color.

export_png(arg, opts \\ [])

Export the canvas using backend. Defaults to PNG; if opts[:format] == :webp and the backend implements export_webp/2, that path is used.

export_png_to_file(handle, path, opts \\ [])

Export PNG and write to file path (helper).

export_raw(arg)

Export the raw RGBA buffer from the backend, if supported.

export_webp(arg, opts \\ [])

Export the canvas as WEBP binary using backend, no filesystem involved.

export_webp_to_file(handle, path, opts \\ [])

Export WEBP and write to file path (helper).

fill_circle(arg, cx, cy, radius, rgba)

Fill a circle with a color.

fill_rect(handle, x, y, w, h)

Fill an axis-aligned rectangle. No-op for backends that don't support it yet; implemented later.

fill_rect(arg, x, y, w, h, rgba)

Fill an axis-aligned rectangle with a color.

hello()

Return a simple atom for smoke tests.

load_font(arg, path)

Load a TTF/OTF font from a filesystem path for the current backend (when supported).

set_antialias(arg, aa)

Enable/disable antialiasing or set sample count (1,4,8).

set_font_size(arg, size)

Set current font size in points/pixels (backend-defined units).

supports?(backend, feature)

Return true if backend supports the given feature

write_binary(bin, path)

Write a binary returned from export_* to a file path (thin helper).

Types

canvas_handle()

@type canvas_handle() :: {module(), term()}

Backend-qualified canvas handle

Functions

capabilities(backend)

@spec capabilities(module()) :: MapSet.t()

Return capabilities supported by the selected backend

clear(arg, rgba)

@spec clear(canvas_handle(), {0..255, 0..255, 0..255, 0..255}) ::
  :ok | {:error, term()}

Clear the canvas to a given RGBA color (tuple {r,g,b,a}, 0..255). No-op for backends that don't support it yet.

create_canvas(width, height, opts \\ [])

@spec create_canvas(pos_integer(), pos_integer(), keyword()) ::
  {:ok, canvas_handle()} | {:error, term()}

Create a new canvas using the selected backend.

Options:

  • :backend - backend module (default: CanvasCraft.Backends.Skia)
  • other backend-specific options

draw_text(arg1, x, y, text, arg2)

@spec draw_text(
  canvas_handle(),
  number(),
  number(),
  String.t(),
  {0..255, 0..255, 0..255, 0..255}
) ::
  :ok | {:error, term()}

Draw UTF-8 text at x,y with RGBA color.

export_png(arg, opts \\ [])

@spec export_png(
  canvas_handle(),
  keyword()
) :: {:ok, binary()} | {:error, term()}

Export the canvas using backend. Defaults to PNG; if opts[:format] == :webp and the backend implements export_webp/2, that path is used.

export_png_to_file(handle, path, opts \\ [])

@spec export_png_to_file(canvas_handle(), Path.t(), keyword()) ::
  :ok | {:error, term()}

Export PNG and write to file path (helper).

export_raw(arg)

@spec export_raw(canvas_handle()) ::
  {:ok, {non_neg_integer(), non_neg_integer(), non_neg_integer(), binary()}}
  | {:error, term()}

Export the raw RGBA buffer from the backend, if supported.

export_webp(arg, opts \\ [])

@spec export_webp(
  canvas_handle(),
  keyword()
) :: {:ok, binary()} | {:error, term()}

Export the canvas as WEBP binary using backend, no filesystem involved.

export_webp_to_file(handle, path, opts \\ [])

@spec export_webp_to_file(canvas_handle(), Path.t(), keyword()) ::
  :ok | {:error, term()}

Export WEBP and write to file path (helper).

fill_circle(arg, cx, cy, radius, rgba)

@spec fill_circle(
  canvas_handle(),
  number(),
  number(),
  number(),
  {0..255, 0..255, 0..255, 0..255}
) ::
  :ok | {:error, term()}

Fill a circle with a color.

fill_rect(handle, x, y, w, h)

@spec fill_rect(canvas_handle(), number(), number(), number(), number()) ::
  :ok | {:error, term()}
@spec fill_rect(canvas_handle(), number(), number(), number(), number()) ::
  :ok | {:error, term()}

Fill an axis-aligned rectangle. No-op for backends that don't support it yet; implemented later.

fill_rect(arg, x, y, w, h, rgba)

@spec fill_rect(
  canvas_handle(),
  number(),
  number(),
  number(),
  number(),
  {0..255, 0..255, 0..255, 0..255}
) :: :ok | {:error, term()}

Fill an axis-aligned rectangle with a color.

hello()

@spec hello() :: :world

Return a simple atom for smoke tests.

load_font(arg, path)

@spec load_font(canvas_handle(), Path.t()) :: :ok | {:error, term()}

Load a TTF/OTF font from a filesystem path for the current backend (when supported).

set_antialias(arg, aa)

@spec set_antialias(canvas_handle(), boolean() | 1 | 4 | 8) :: :ok | {:error, term()}

Enable/disable antialiasing or set sample count (1,4,8).

set_font_size(arg, size)

@spec set_font_size(canvas_handle(), number()) :: :ok | {:error, term()}

Set current font size in points/pixels (backend-defined units).

supports?(backend, feature)

@spec supports?(module(), atom()) :: boolean()

Return true if backend supports the given feature

write_binary(bin, path)

@spec write_binary(binary(), Path.t()) :: :ok | {:error, term()}

Write a binary returned from export_* to a file path (thin helper).