PrismTypes
Public TypeScript types exported from the package root.
All public Prism imports come from the package root:
import {
CanvasRuntime,
type CanvasRuntimeOptions,
type CanvasSurface,
type SurfaceOptions
} from "@synthesisengineering/prism";Do not import runtime internals, backend classes, paint-pass helpers, or platform wrappers from subpaths.
Runtime
type CanvasBackendKind = "native" | "fallback";
type CanvasBackendPreference = "auto" | CanvasBackendKind;
type CanvasRuntimeOptions = Readonly<{
backend?: CanvasBackendPreference;
nativePaintTimeoutMs?: number;
}>;nativePaintTimeoutMs defaults to 2000 ms and must be finite, greater than 0 and at most 2147483647. It counts visible time for pending paintOnce() callers. See paintOnce().
type CanvasDiagnostics = Readonly<{
backend: CanvasBackendKind;
capability: "supported" | "unavailable" | "unsupported-version";
health?: "idle" | "pending" | "healthy" | "failed";
lastError?: PrismNativeError;
}>;runtime.diagnostics returns this snapshot. Capability describes API presence; native health describes the last paint outcome. Fallback diagnostics omit health and lastError.
PrismNativeError extends Error. Its code is "draw-failed" or "paint-timeout"; draw failures retain the original exception as cause. Import it from the package root.
Surface
type SurfaceBoundsInput =
| RectLike
| (() => RectLike);
type SurfaceOptions = Readonly<{
bounds: SurfaceBoundsInput;
ariaLabel?: string;
}>;Surface bounds are CSS pixels.
Paint and Update
type UpdateHandler = (time: FrameTime) => void;
type PaintHandler = (api: {
ctx: CanvasRenderingContext2D;
time: FrameTime;
drawSurface: (surface: CanvasSurface) => void;
invalidate: () => void;
}) => void;Direct drawing with ctx uses backing-store pixels. Registered surfaces use CSS-pixel bounds and should be drawn with drawSurface(surface).
Coordinates
type CanvasPoint = Readonly<{
x: number;
y: number;
}>;clientToCanvasPoint() returns CSS-pixel coordinates. cssLengthToCanvasPixels() and cssPointToCanvasPixels() convert CSS-space values for direct canvas drawing.