shrink imagies

src/components/NewPostWidget.tsx

@@ -2,6 +2,7 @@ import { useState } from 'react'
 import FancyTextEditor, { TextInputKeyDownEvent } from './inputs/FancyTextEditor.tsx'
 import Button from './buttons/Button.tsx'
 import { openFileDialog } from '../utils/openFileDialog.ts'
+import makePica from 'pica'
 
 interface NewPostWidgetProps {
   onSubmit: (
@@ -121,11 +122,13 @@ async function createAttachment(file: File): Promise<Attachment> {
     throw new Error('not an image')
   }
 
+  file = await optimizeImageSize(file)
+
   const objectUrl = URL.createObjectURL(file)
   const { width, height } = await getImageFileDimensions(objectUrl)
 
   return {
-    id: crypto.randomUUID(),
+    id: getRandomId(),
     file,
     objectUrl,
     width,
@@ -144,3 +147,82 @@ function getImageFileDimensions(objectURL: string): Promise<{ width: number; hei
     img.src = objectURL
   })
 }
+
+const pica = makePica()
+
+async function optimizeImageSize(
+  file: File,
+  {
+    targetMaxWidth = 1920,
+    targetMaxHeight = 1080,
+    targetSizeBytes = 500 * 1024,
+    outputType = 'image/jpeg',
+    quality = 0.9,
+  }: {
+    targetMaxWidth?: number
+    targetMaxHeight?: number
+    targetSizeBytes?: number
+    outputType?: string
+    quality?: number
+  } = {},
+): Promise<File> {
+  const img = document.createElement('img')
+  const url = URL.createObjectURL(file)
+  img.src = url
+
+  await img.decode()
+
+  console.debug('processing image', {
+    width: img.width,
+    height: img.height,
+    targetMaxWidth,
+    targetMaxHeight,
+    targetSizeBytes,
+    outputType,
+    quality,
+  })
+
+  const scale = Math.min(1, targetMaxWidth / img.width, targetMaxHeight / img.height)
+  const width = Math.floor(img.width * scale)
+  const height = Math.floor(img.height * scale)
+
+  const srcCanvas = document.createElement('canvas')
+  srcCanvas.width = img.width
+  srcCanvas.height = img.height
+  srcCanvas.getContext('2d')!.drawImage(img, 0, 0)
+
+  const dstCanvas = document.createElement('canvas')
+  dstCanvas.width = width
+  dstCanvas.height = height
+
+  await pica.resize(srcCanvas, dstCanvas)
+
+  let blob = await pica.toBlob(dstCanvas, outputType, quality)
+
+  while (blob.size > targetSizeBytes && quality > 0.1) {
+    quality = parseFloat((quality - 0.1).toFixed(2))
+    blob = await pica.toBlob(dstCanvas, outputType, quality)
+  }
+
+  URL.revokeObjectURL(url)
+
+  return new File([blob], file.name, { type: file.type })
+}
+
+function getRandomId() {
+  if (window.isSecureContext) {
+    return crypto.randomUUID()
+  }
+
+  // Fallback using getRandomValues
+  const bytes = new Uint8Array(16)
+  crypto.getRandomValues(bytes)
+
+  // Format according to RFC4122 version 4
+  bytes[6] = (bytes[6]! & 0x0f) | 0x40
+  bytes[8] = (bytes[8]! & 0x3f) | 0x80
+
+  const hex = [...bytes].map((b) => b.toString(16).padStart(2, '0'))
+
+  return `${hex.slice(0, 4).join('')}-${hex.slice(4, 6).join('')}-${hex.slice(6, 8).join('')}-${hex.slice(8, 10).join('')}-${hex.slice(10, 16).join('')}`
+}