A wx (wxWidgets) backend for Easel that renders draw operations to a native window using wxGraphicsContext.
Uses :wx_object for proper OTP lifecycle management and
double buffering via wxBitmap + wxMemoryDC for flicker-free rendering.
Requires Erlang compiled with wx support. When wx is not available,
render/2 and animate/5 will raise at runtime.
Usage
canvas =
Easel.new(400, 300)
|> Easel.set_fill_style("blue")
|> Easel.fill_rect(50, 50, 100, 100)
|> Easel.set_stroke_style("red")
|> Easel.set_line_width(3)
|> Easel.stroke_rect(50, 50, 100, 100)
|> Easel.render()
# Opens a wx window and draws the operations
Easel.WX.render(canvas)Animation
Easel.WX.animate(600, 400, initial_state, fn state ->
{canvas, new_state} = MyApp.tick(state)
{canvas, new_state}
end, title: "Animation")Supported operations
Drawing: fillRect, strokeRect, clearRect, fillText, strokeText
Paths: beginPath, closePath, moveTo, lineTo, arc, ellipse,
rect, bezierCurveTo, quadraticCurveTo, arcTo, fill, stroke
Styles: fillStyle, strokeStyle, lineWidth, lineCap, lineJoin,
font, globalAlpha
Transforms: save, restore, translate, rotate, scale,
setTransform, resetTransform, transform
Unsupported operations
Operations that have no wx equivalent will raise Easel.WX.UnsupportedOpError.
These include: shadows, filters, compositing modes, image data, patterns,
gradients, clipping, and text measurement.
Summary
Functions
Runs an animation loop in a wx window.
Returns true if wx is available in the current Erlang runtime.
Parses a CSS color string into an {r, g, b, a} tuple.
Parses a CSS font shorthand string into {size, face, style, weight}.
Renders an Easel struct to a wx window.
Functions
Runs an animation loop in a wx window.
Takes a width, height, initial state, and a function that receives
the current state and returns {%Easel{}, new_state}. The function
is called every interval milliseconds (default 16, ~60fps).
The loop runs until the window is closed, then returns :ok.
Options
:title- window title (default"Easel"):interval- milliseconds between frames (default16):on_click-fn x, y, state -> new_state endcalled on mouse click:on_mouse_down-fn x, y, state -> new_state end:on_mouse_up-fn x, y, state -> new_state end:on_mouse_move-fn x, y, state -> new_state end:on_key_down-fn key_event, state -> new_state end
Event handlers for animate receive the current state and must return
the new state. The updated state will be used by the next tick.
Example
Easel.WX.animate(600, 400, initial_state, fn state ->
{canvas, new_state} = MyApp.tick(state)
{canvas, new_state}
end, title: "Animation", on_click: fn x, y, state ->
%{state | target: {x, y}}
end)Returns true if wx is available in the current Erlang runtime.
Parses a CSS color string into an {r, g, b, a} tuple.
Supports named colors, hex (#rgb, #rrggbb, #rrggbbaa),
rgb(), and rgba().
Parses a CSS font shorthand string into {size, face, style, weight}.
Returns a tuple of {integer, charlist, wx_style_atom, wx_weight_atom}.
Renders an Easel struct to a wx window.
Opens a native window, draws all operations, and blocks until the window is closed by the user.
Options
:title- window title (default"Easel"):on_click-fn x, y -> ... endcalled on mouse click:on_mouse_down-fn x, y -> ... endcalled on mouse button press:on_mouse_up-fn x, y -> ... endcalled on mouse button release:on_mouse_move-fn x, y -> ... endcalled on mouse movement:on_key_down-fn key_event -> ... endcalled on key press