Function maybeResizeAndDownsampleImageBlock

src/utils/imageResizer.ts:445–481

(
  imageBlock: ImageBlockParam,
)

 * Also returns dimension information for coordinate mapping
 */
export async function maybeResizeAndDownsampleImageBlock(
  imageBlock: ImageBlockParam,
): Promise<ImageBlockWithDimensions> {
  // Only process base64 images
  if (imageBlock.source.type !== 'base64') {
    return { block: imageBlock }
  }

  // Decode base64 to buffer
  const imageBuffer = Buffer.from(imageBlock.source.data, 'base64')
  const originalSize = imageBuffer.length

  // Extract extension from media type
  const mediaType = imageBlock.source.media_type
  const ext = mediaType?.split('/')[1] || 'png'

  // Resize if needed
  const resized = await maybeResizeAndDownsampleImageBuffer(
    imageBuffer,
    originalSize,
    ext,
  )

  // Return resized image block with dimension info
  return {
    block: {
      type: 'image',
      source: {
        type: 'base64',
        media_type:
          `image/${resized.mediaType}` as Base64ImageSource['media_type'],
        data: resized.buffer.toString('base64'),
      },
    },
    dimensions: resized.dimensions,
  }
}

/**
 * Compresses an image buffer to fit within a maximum byte size.