vadim
f0706432d4
Gitea Actions / Deploy (push) Successful in 29s
sessions fix password change sign-in fix
30 lines
1.1 KiB
TypeScript
30 lines
1.1 KiB
TypeScript
/**
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* Shrinks an image so its longest side is at most `maxSize` px before upload.
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* GIFs are kept as is (canvas would drop the animation), as are images the
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* browser cannot decode — the server decides what to do with those.
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*/
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export async function resizeImage(file: File, maxSize: number): Promise<File> {
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if (file.type === 'image/gif') return file
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let bitmap: ImageBitmap
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try {
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bitmap = await createImageBitmap(file)
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} catch {
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return file
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}
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const scale = Math.min(1, maxSize / Math.max(bitmap.width, bitmap.height))
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const canvas = document.createElement('canvas')
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canvas.width = Math.round(bitmap.width * scale)
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canvas.height = Math.round(bitmap.height * scale)
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canvas.getContext('2d')?.drawImage(bitmap, 0, 0, canvas.width, canvas.height)
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bitmap.close()
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// Browsers without WebP encoding (Safari) fall back to PNG
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const blob = await new Promise<Blob | null>((resolve) => canvas.toBlob(resolve, 'image/webp', 0.9))
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if (!blob || blob.size >= file.size) return file
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const ext = blob.type === 'image/webp' ? 'webp' : 'png'
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return new File([blob], `${file.name.replace(/\.[^.]+$/, '')}.${ext}`, { type: blob.type })
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}
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