Maofeng
60 lines
1.7 KiB
TypeScript
60 lines
1.7 KiB
TypeScript
export interface MediaDimensions {
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height: number
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width: number
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}
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const METADATA_TIMEOUT_MS = 10_000
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function waitForDimensions(
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file: File,
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element: HTMLImageElement | HTMLVideoElement,
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successEvent: "load" | "loadedmetadata"
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): Promise<MediaDimensions | undefined> {
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return new Promise((resolve) => {
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const objectUrl = URL.createObjectURL(file)
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let settled = false
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const timeout = window.setTimeout(finish, METADATA_TIMEOUT_MS)
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function finish(dimensions?: MediaDimensions) {
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if (settled) return
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settled = true
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window.clearTimeout(timeout)
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URL.revokeObjectURL(objectUrl)
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resolve(dimensions)
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}
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element.addEventListener(
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successEvent,
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() => {
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const width =
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element instanceof HTMLVideoElement
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? element.videoWidth
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: element.naturalWidth
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const height =
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element instanceof HTMLVideoElement
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? element.videoHeight
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: element.naturalHeight
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finish(width > 0 && height > 0 ? { height, width } : undefined)
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},
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{ once: true }
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)
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element.addEventListener("error", () => finish(), { once: true })
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element.src = objectUrl
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})
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}
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/** Reads intrinsic dimensions before an adapter uploads an image or video. */
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export function readMediaDimensions(
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file: File
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): Promise<MediaDimensions | undefined> {
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if (file.type.startsWith("image/")) {
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return waitForDimensions(file, new Image(), "load")
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}
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if (file.type.startsWith("video/")) {
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const video = document.createElement("video")
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video.preload = "metadata"
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return waitForDimensions(file, video, "loadedmetadata")
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}
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return Promise.resolve(undefined)
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}
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