import type { CellMetrics } from "./measure";
export type RendererBackend = "webgpu" | "webgl2" | "canvas2d";
/** Relative luminance of an 0-255 RGB triple, in the same (sRGB-encoded)
 *  space the glyph shader compares foreground colours in. */
export declare function rgbLuma(rgb: [number, number, number]): number;
export interface GlRenderer {
    supported: boolean;
    backend?: RendererBackend;
    maxDimension: number;
    /** Coverage gamma for glyph antialiasing. 1 leaves coverage untouched;
     *  above 1 thins light-on-dark text. See GLYPH_FS. */
    setTextGamma(gamma: number): void;
    resize(width: number, height: number): void;
    render(bgVerts: Float32Array, glyphVerts: Float32Array, atlasCanvas: HTMLCanvasElement | undefined, atlasVersion: number, cursorVisible: boolean, cursorCol: number, cursorRow: number, cursorStyle: number, cursorBlinkOn: boolean, cell: CellMetrics, bgColor: [number, number, number], focused?: boolean): void;
    dispose(): void;
}
/**
 * Software fallback when WebGL2 is not available (e.g. headless compositor
 * without GPU).  Reads the same vertex buffers produced by the WASM terminal
 * and paints them with Canvas 2D.
 */
export declare function createCanvas2dRenderer(canvas: HTMLCanvasElement): GlRenderer;
export declare function createGlRenderer(canvas: HTMLCanvasElement, 
/** Called once if the drawing context is lost. The renderer is unusable from
 *  that point on — see the `webglcontextlost` handler below. */
onLost?: () => void): GlRenderer;
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