/**
 * Cached single-line text measurement, shared by the Text shader's rasterizer and its
 * bounding-box computeBounds in the Design Editor.
 *
 * Everything is measured at a fixed 100px reference size: width scales linearly with font
 * size (letter-spacing is em-based), so resizing text is pure math — no re-measure, and the
 * cache key excludes font size entirely.
 *
 * Cache entries are keyed on the font's live availability (document.fonts.check), so when a
 * webfont finishes loading the next measure misses the stale fallback-font entry and re-measures
 * with the real font — even across separate bundle instances of this module (the editor and the
 * renderer each carry their own cache, but document.fonts is page-global).
 */
export type TextTransformMode = 'none' | 'uppercase' | 'lowercase' | 'capitalize';
export interface TextMeasureSpec {
    text: string;
    fontFamily: string;
    fontWeight: number;
    italic: boolean;
    letterSpacingEm: number;
    textTransform: TextTransformMode;
}
export interface TextMeasureResult {
    /** Advance width of the run at 100px font size. */
    widthPer100: number;
    /** Font ascent above the alphabetic baseline at 100px font size. */
    ascentPer100: number;
    /** Font descent below the alphabetic baseline at 100px font size. */
    descentPer100: number;
    /**
     * INK extents — the actual glyph bounding box of THIS run (actualBoundingBox*), not the
     * font box. This is what "the box hugs the text" means: a caps-only run has near-zero ink
     * descent while its font descent stays fixed. Falls back to the font box when unavailable.
     * Consumers: Text's computeBounds (tight layout stacking / overlay box).
     */
    inkAscentPer100: number;
    inkDescentPer100: number;
}
/** Applies the text-transform mode. Used before both measuring and rasterizing. */
export declare function applyTextTransform(text: string, mode: TextTransformMode | string | undefined): string;
export declare function bumpMeasureGeneration(): void;
/** Whether canvas letter-spacing is supported (Chrome 99+/Safari 17.4+/FF 97+). */
export declare function supportsCanvasLetterSpacing(): boolean;
/**
 * Measures a single-line run at the 100px reference size. Cached; safe to call per-frame.
 * Falls back to a rough estimate when no 2D context is available (SSR).
 */
export declare function measureText(spec: TextMeasureSpec): TextMeasureResult;
/**
 * Greedy word wrap — pure, measurer-injected (unit-testable without a canvas).
 * Explicit lines are wrapped independently; a word longer than the max overflows on its own
 * line (Figma behaviour — no mid-word breaking). maxWidthPer100 <= 0 disables wrapping.
 */
export declare function wrapLines(text: string, maxWidthPer100: number, measureLine: (line: string) => number): string[];
export interface TextBlockMeasure {
    /** Final lines (explicit breaks + wrapping), post-textTransform. */
    lines: string[];
    /** Advance width of each line at the 100px reference. */
    lineWidthsPer100: number[];
    /** Widest line advance. */
    widthPer100: number;
    /** Font-box ascent/descent (shared by all lines). */
    ascentPer100: number;
    descentPer100: number;
    /** Ink extents of the FIRST line's top and the LAST line's bottom. */
    inkAscentFirstPer100: number;
    inkDescentLastPer100: number;
    /** Baseline-to-baseline distance: lineHeightEm × 100. */
    pitchPer100: number;
    /** Font-box block: ascent + (n−1)·pitch + descent. */
    blockHeightPer100: number;
    /** Ink block: inkAscentFirst + (n−1)·pitch + inkDescentLast. */
    inkHeightPer100: number;
}
/**
 * Measures a multi-line block at the 100px reference. Wrap points depend only on the
 * width÷fontSize ratio, so a caller passes `maxWidthPer100 = maxWidthPx × 100 / fontSizePx`
 * and the whole block stays linear in fontSize — the same scaling trick single-line
 * measurement has always used. Per-line measurement goes through the cached measureText.
 */
export declare function measureTextBlock(spec: TextMeasureSpec, lineHeightEm: number, maxWidthPer100?: number): TextBlockMeasure;
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