towsty
a9bf4f6a95
Keep video output on the still by default, and only force 16:9, 9:16, or 1:1 when a preset is selected.
101 lines
3.3 KiB
TypeScript
101 lines
3.3 KiB
TypeScript
const SHORT_EDGE = 768
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const LONG_EDGE = 1344
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export const ASPECT_PRESETS: Record<string, { width: number; height: number }> = {
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'16:9': { width: 1344, height: 768 },
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'9:16': { width: 768, height: 1344 },
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'1:1': { width: 1024, height: 1024 }
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}
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export function snap32(value: number) {
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return Math.max(32, Math.round(value / 32) * 32)
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}
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/** Fit the source still to H3's native 768 short-edge canvas, 32px grid, 1344 long-edge cap. */
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export function autoResolution(srcWidth: number, srcHeight: number) {
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const ratio = srcWidth / Math.max(srcHeight, 1)
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let width: number
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let height: number
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if (ratio >= 1) {
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height = SHORT_EDGE
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width = Math.min(LONG_EDGE, height * ratio)
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} else {
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width = SHORT_EDGE
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height = Math.min(LONG_EDGE, width / ratio)
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}
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width = snap32(width)
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height = snap32(height)
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if (width > LONG_EDGE) width = LONG_EDGE
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if (height > LONG_EDGE) height = LONG_EDGE
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return { width: Math.max(32, width), height: Math.max(32, height) }
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}
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export function imageDimensions(buf: Buffer) {
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if (buf.length < 24) return null
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if (buf[0] === 0x89 && buf[1] === 0x50 && buf[2] === 0x4e && buf[3] === 0x47) {
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return { width: buf.readUInt32BE(16), height: buf.readUInt32BE(20) }
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}
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if (buf[0] === 0x47 && buf[1] === 0x49 && buf[2] === 0x46) {
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return { width: buf.readUInt16LE(6), height: buf.readUInt16LE(8) }
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}
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if (buf[0] === 0x42 && buf[1] === 0x4d && buf.length >= 26) {
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return { width: buf.readInt32LE(18), height: Math.abs(buf.readInt32LE(22)) }
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}
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if (buf.toString('ascii', 0, 4) === 'RIFF' && buf.toString('ascii', 8, 12) === 'WEBP') {
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return webpSize(buf)
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}
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if (buf[0] === 0xff && buf[1] === 0xd8) {
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return jpegSize(buf)
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}
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return null
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}
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function webpSize(buf: Buffer) {
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const kind = buf.toString('ascii', 12, 16)
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if (kind === 'VP8X' && buf.length >= 30) {
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const width = 1 + buf[24] + (buf[25] << 8) + (buf[26] << 16)
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const height = 1 + buf[27] + (buf[28] << 8) + (buf[29] << 16)
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return { width, height }
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}
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if (kind === 'VP8 ' && buf.length >= 30) {
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return { width: buf.readUInt16LE(26) & 0x3fff, height: buf.readUInt16LE(28) & 0x3fff }
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}
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if (kind === 'VP8L' && buf.length >= 25) {
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const bits = buf.readUInt32LE(21)
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return { width: (bits & 0x3fff) + 1, height: ((bits >> 14) & 0x3fff) + 1 }
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}
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return null
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}
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function jpegSize(buf: Buffer) {
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let offset = 2
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while (offset + 9 < buf.length) {
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if (buf[offset] !== 0xff) return null
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const marker = buf[offset + 1]
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if (marker === 0xd8 || marker === 0xd9) {
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offset += 2
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continue
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}
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const length = buf.readUInt16BE(offset + 2)
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if (marker >= 0xc0 && marker <= 0xc3) {
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return { width: buf.readUInt16BE(offset + 7), height: buf.readUInt16BE(offset + 5) }
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}
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offset += 2 + length
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}
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return null
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}
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export function resolveOutputSize(aspect: string | undefined, image: Buffer, fallbackWidth?: number, fallbackHeight?: number) {
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if (aspect && ASPECT_PRESETS[aspect]) {
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return ASPECT_PRESETS[aspect]
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}
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const fromFields = Number(fallbackWidth) && Number(fallbackHeight)
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? { width: snap32(Number(fallbackWidth)), height: snap32(Number(fallbackHeight)) }
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: null
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const size = imageDimensions(image)
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if (size?.width && size?.height) {
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return autoResolution(size.width, size.height)
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}
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return fromFields || ASPECT_PRESETS['16:9']
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}
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