| 1 | export type PresentationFontSize = "S" | "M" | "L" | undefined; |
| 2 | |
| 3 | // Returns CSS variables for heading/paragraph sizes based on slide font size. |
| 4 | // Current values reflect the previous M defaults and act as fallback when size is undefined. |
| 5 | export function getTypographyCSSVariables(size: PresentationFontSize) { |
| 6 | // M defaults match previous static values |
| 7 | const baseM = { |
| 8 | h1: 3, |
| 9 | h2: 1.875, |
| 10 | h3: 1.5, |
| 11 | h4: 1.25, |
| 12 | h5: 1.125, |
| 13 | h6: 1, |
| 14 | p: 1, |
| 15 | } as const; |
| 16 | |
| 17 | // Scale factors derived from container base font px: S=12, M=16, L=18 |
| 18 | // Relative to M: S = 12/16 = 0.75, L = 18/16 = 1.125 |
| 19 | const factor = size === "S" ? 0.75 : size === "L" ? 1.125 : 1; |
| 20 | |
| 21 | const scaled = { |
| 22 | h1: `${round(baseM.h1 * factor)}em`, |
| 23 | h2: `${round(baseM.h2 * factor)}em`, |
| 24 | h3: `${round(baseM.h3 * factor)}em`, |
| 25 | h4: `${round(baseM.h4 * factor)}em`, |
| 26 | h5: `${round(baseM.h5 * factor)}em`, |
| 27 | h6: `${round(baseM.h6 * factor)}em`, |
| 28 | p: `${round(baseM.p * factor)}em`, |
| 29 | } as const; |
| 30 | |
| 31 | return { |
| 32 | "--presentation-h1-size": scaled.h1, |
| 33 | "--presentation-h2-size": scaled.h2, |
| 34 | "--presentation-h3-size": scaled.h3, |
| 35 | "--presentation-h4-size": scaled.h4, |
| 36 | "--presentation-h5-size": scaled.h5, |
| 37 | "--presentation-h6-size": scaled.h6, |
| 38 | "--presentation-p-size": scaled.p, |
| 39 | } as Record<string, string>; |
| 40 | } |
| 41 | |
| 42 | function round(value: number): string { |
| 43 | // Keep up to 3 decimals to avoid noisy values like 2.109375 |
| 44 | return Number(Math.round((value + Number.EPSILON) * 1000) / 1000).toString(); |
| 45 | } |
| 46 |