kei-lisp-plugin-graphics - v4.0.0
    Preparing search index...

    Class GraphicsPlugin

    Canvas2D drawing plugin for the kei-lisp interpreter. Implements the KeiLispPlugin contract (name / has / apply) and exposes 75 g… Lisp functions that proxy to a 2D rendering context. Failures (wrong arity, type mismatch, closed canvas, canvas-level errors) signal an EvalError that Lisp callers can intercept with (handler-case … (eval-error (e) …)). Two exceptions still go to process.stderr as diagnostics: asynchronous work (image loading, OffscreenCanvas file writes), which fails after the call has returned, and selectColor's best-effort color parsing, which falls back to black instead of failing.

    Keisuke Ikeda

    Implements

    • KeiLispPlugin
    Index

    Constructors

    constructor

    Properties

    canvas ctx isOpen name

    Methods

    apply gAlpha gArc gArcTo gBezCurveTo gClear gClearRect gClip gClose gColor gComposite gConicGradient gEllipse gFill gFillColor gFillRect gFillText gFillTri gFilter gFinishPath gFontKerning gFontStretch gFontVariant gHeight gImage gImageSmoothing gIsPointInPath gIsPointInStroke gLetterSpacing gLinearGradient gLineCap gLineDash gLineDashOffset gLineJoin gLineTo gLineWidth gMeasureText gMiterLimit gMoveTo gOpen gPattern gPixel gQuadCurveTo gRadialGradient gRect gReset gResetTransform gRestore gRotate gRoundRect gSave gSaveJpeg gSavePng gScale gSetPixel gSetTransform gShadowBlur gShadowColor gShadowOffsetX gShadowOffsetY gSleep gStartPath gStroke gStrokeColor gStrokeRect gStrokeText gStrokeTri gTextAlign gTextBaseline gTextDirection gTextFont gTextRendering gTransform gTranslate gWidth gWordSpacing has saveCanvas selectColor functionNames

    Constructors

    Properties

    canvas: HTMLCanvasElement | OffscreenCanvas
    ctx: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D | null
    isOpen: boolean
    name: string = 'graphics'

    Plugin identifier, used for diagnostics.

    Methods

    • Dispatches the given symbol to the matching g… method.

      Parameters

      • aSymbol: InterpretedSymbol

        the call symbol

      • arguments_: Cons

        the evaluated argument list

      • _context: PluginContext

        the interpreter context (unused by this plugin)

      Returns LispValue

      the method's result

    • Pops the most recently saved drawing state off the context's state stack. Pairs with gSave. Popping an empty stack is a no-op per the Canvas spec.

      Parameters

      • arguments_: Cons = Cons.nil

      Returns LispValue

      t on success

    • Pushes the current drawing state (styles, transform, clip) onto the context's state stack. Pairs with gRestore to let Lisp callers manage state explicitly. Replaces the legacy per-method context.save() calls, which pushed state on every draw with no matching restore() and grew the stack unbounded.

      Parameters

      • arguments_: Cons = Cons.nil

      Returns LispValue

      t on success

    • Returns true if this plugin handles the given symbol.

      Parameters

      • aSymbol: InterpretedSymbol

        the call symbol

      Returns boolean

      true if apply should be called

    • Shared implementation of gsave-jpeg / gsave-png. With no argument it triggers a browser download; with a single string argument it writes the encoded image to that file path on Node.js.

      Parameters

      • arguments_: Cons

        the evaluated argument list (empty, or one path string)

      • mimeType: string

        the image MIME type to encode

      • label: string

        the format name used in diagnostics ("jpeg" / "png")

      Returns LispValue

      t on success

    • Parses a color spec from the head of the argument Cons. Accepts (1 string), (3 numbers — rgb), or (4 numbers — rgba); falls back to 'black' on anything else (legacy behavior — a best-effort color parse that prints a diagnostic instead of signaling an error).

      Parameters

      • arguments_: Cons

        the argument Cons to parse

      Returns string

      CSS color string

    • Lists every Lisp function name this plugin registers.

      Returns string[]

      the sorted g… function names

    Settings

    Member Visibility

    On This Page

    Constructors
    Properties
    Methods