| 1 | export interface BrowserViewport { width: number; height: number; scale: "fit" | number } |
| 2 | export function validateViewport(input: BrowserViewport): BrowserViewport { |
| 3 | if (!Number.isInteger(input.width) || input.width < 320 || input.width > 3840 || !Number.isInteger(input.height) || input.height < 320 || input.height > 2160) throw new Error("viewport must be 320–3840 × 320–2160 CSS pixels"); |
| 4 | if (input.scale !== "fit" && ![0.5, 0.75, 1, 1.25, 1.5, 2].includes(input.scale)) throw new Error("unsupported viewport display scale"); |
| 5 | return { ...input }; |
| 6 | } |
| 7 | export function viewportScale(viewport: BrowserViewport | null, surface: { width: number; height: number }): number { |
| 8 | if (!viewport) return 1; |
| 9 | return viewport.scale === "fit" ? Math.max(0.05, Math.min(surface.width / viewport.width, surface.height / viewport.height, 2)) : viewport.scale; |
| 10 | } |
| 11 |